| corticotropin-releasing factor stimulates metamorphosis and increases thyroid hormone concentration in prometamorphic rana perezi larvae. | attempts to identify a hypothalamic molecule that stimulates thyrotropin (tsh) secretion from amphibian pituitary have been unsuccessful to date. the effects of mammalian (ovine and human) corticotropin-releasing factor (crf) on the thyroid function of prometamorphic (taylor & kollros stages xi-xvii) (taylor and kollros, 1946) rana perezi larvae were studied. chronic treatments with both ovine and human crf (ocrf, hcrf) stimulated metamorphosis while delaying larval growth. chronic hcrf (1 micro ... | 1992 | 1624098 |
| effects of ovine crf on amphibian pituitary acth and tsh cells in vivo: a quantitative ultrastructural study. | the subcellular responses of amphibian adrenocorticotropic (acth) and thyrotropic (tsh) pituitary cells to the in vivo administration of ovine corticotropin-releasing factor was investigated. for this purpose, groups of six rana perezi adult frog (three males and three females) were given daily injections of ovine crf and sacrificed at 6 hr, 24 hr, and 4 days after the first injection. immunogold staining, applied to ultrathin sections using antisera to human acth (1-39) and human beta-tsh ident ... | 1991 | 1657693 |
| human pancreatic growth hormone-releasing factor (1-44) stimulates gh cells in an anuran amphibian (rana perezi). | subcellular responses of amphibian growth hormone (gh)-producing cells to in vivo administration of human pancreatic growth hormone-releasing factor (1-44) (hpgrf) were investigated. the volume density (vv) of secretory granules (sg), rough endoplasmic reticulum (rer), and golgi complex (gc) and the numerical density (nv) of the granules were estimated by ultrastructural morphometry. immunogold staining was applied to ultrathin sections using an antiserum to ovine gh to identify gh-producing cel ... | 1991 | 1808027 |
| amphibian alcohol dehydrogenase, the major frog liver enzyme. relationships to other forms and assessment of an early gene duplication separating vertebrate class i and class iii alcohol dehydrogenases. | submammalian alcohol dehydrogenase structures can be used to evaluate the origins and functions of the different types of the mammalian enzyme. two avian forms were recently reported, and we now define the major amphibian alcohol dehydrogenase. the enzyme from the liver of the green frog rana perezi was purified, carboxymethylated, and submitted to amino acid sequence determination by peptide analysis of six different digests. the protein has a 375-residue subunit and is a class i alcohol dehydr ... | 1991 | 2007119 |
| effect of natural ageing and antioxidant inhibition on liver antioxidant enzymes, glutathione system, peroxidation, and oxygen consumption in rana perezi. | a study of the physiological role of oxygen free radicals in relation to the ageing process was performed using the liver of rana perezi, an animal with a moderate rate of oxygen consumption and a life span substantially longer than that of laboratory rodents. among the five different antioxidant enzymes only superoxide dismutase (sod) showed an age-dependent decrease. cytochrome oxidase (cox), glutathione status, in vivo and in vitro liver peroxidation, and metabolic rate did not vary as a func ... | 1991 | 2045545 |
| lung antioxidant enzymes, peroxidation, glutathione system and oxygen consumption in catalase inactivated young and old rana perezi frogs. | in the lung of rana perezi no differences as a function of age have been found for any of the five major antioxidant enzymes, reduced (gsh), oxidized (gssg) or glutathione ratio (gssg/gsh), oxygen consumption (vo2) and for in vivo or in vitro stimulated tissue peroxidation. this frog shows a moderate rate of oxygen consumption and a life span substantially longer than that of rats and mice. chronic (2.5 months) catalase depletion in the lung did not affect survival or any additional antioxidant ... | 1990 | 2089200 |
| changes on cerebral antioxidant enzymes, peroxidation, and the glutathione system of frogs after aging and catalase inhibition. | the five major antioxidant enzymes, glutathione, and in vivo or in vitro stimulated (fe(++)-ascorbate) peroxidation were similar in old and young rana perezi frogs. long-term (2.5 months) treatment with aminotriazole strongly decreased cerebral catalase (cat) activity and increased in vivo but not in vitro peroxidation in the brain. this suggests that the increase in endogenous brain peroxidation after cat inhibition is due to an increased free-radical attack on cerebral membranes, and not to a ... | 1990 | 2168950 |
| aminotriazole effects on lung and heart h2o2 detoxifying enzymes and tba-rs at two po2. | in order to clarify the physiological role in vivo of h2o2-detoxifying enzymes at low and high levels of o2 tension we studied catalase (cat), glutathione peroxidases (gp), and in vivo peroxidation (tba-rs) in the lung and heart of rana perezi frogs chronically treated with hyperoxia, aminotriazole (at) -a cat inhibitor-, or both. hyperoxia did not change cat, gp or tba-rs. aminotriazole caused an almost complete depletion of cat, a 30% decrease of gp and a 132% (lung) to 200% (heart) increase o ... | 1990 | 2308904 |
| morphometric evaluation of subcellular changes induced by in vivo trh treatment in the pituitary gland of rana perezi: effects on prolactin and thyrotropic cells. | the effects of synthetic thyrotropin-releasing hormone on pituitary prolactin and thyrotropic cells were investigated in adult male rana perezi (formerly rana ridibunda) frogs. animals were given daily injections of synthetic thyrotropin-releasing hormone into the dorsal lymph sac. prolactin and thyrotropic cells were identified by the colloidal-gold method, using anti-human prolactin and anti-human-beta-thyrotropin hormone as primary antisera. the stereological parameters of the rough endoplasm ... | 1989 | 2499423 |
| catalase is needed to avoid tissue peroxidation in rana perezi in normoxia. | 1. in order to clarify the relative role of catalase (cat) and glutathione peroxidases (gsh-px) at normal and high o2 tensions, rana perezi frogs were chronically treated with aminotriazole (at), hyperoxia, or both. 2. a 100% survival was observed with both treatments. hyperoxia increased liver catalase and kidney tba-rs and decreased gsh-px. 3. at caused quantitatively higher alterations than hyperoxia in both organs: cat was depleted, tba-rs increased (114% in kidney) and gsh-px decreased. 4. ... | 1989 | 2576777 |
| histochemistry of glycoconjugates in the gallbladder epithelium of ten animal species. | a battery of seven lectins and several conventional mucin histochemical techniques were used to identify the epithelial mucins of the gallbladder of ten species: man, rabbit (oryctolagus cuniculus, mammalia), hamster (mesocricetus auratus, mammalia), chicken (gallus gallus, bird), sparrow (passer domesticus, bird), moorish gecko (tarentola mauritanica, reptilia), ladder snake (elaphe scalaris, reptilia), lake frog (rana perezi, amphibia), natterjack toad (bufo calamita, amphibia) and gilthead se ... | 1989 | 2722572 |
| immunocytochemical and morphometric study of prolactin cells during amphibian morphogenesis. | the peroxidase-antiperoxidase (pap) immunocytochemical technique and rabbit antihuman prolactin (prl) antiserum were used to localize and identify prl-producing cells in the pars distalis of bufo calamita, hyla meridionalis, alytes cisternasii, pelobates cultripes, and rana perezi tadpoles at different stages of development as well as in 1-year-old post-metamorphic animals. this cell type was located throughout the gland in p. cultripes and r. perezi and in the caudal two-thirds in b. calamita, ... | 1988 | 3284780 |
| immunohistochemical localization of thyrotropic cells during amphibian morphogenesis: a stereological study. | tsh-like producing cells have been studied using the peroxidase-antiperoxidase (pap) immunohistochemical technique and rabbit anti-human thyrotropin (tsh) antiserum in the pars distalis of five species of amphibian anuran tadpoles at different stages of development as well as in 1-year-old postmetamorphic animals. this cell type has been identified and located in the pars distalis ventral zone of bufo calamita showing no changes in its distribution pattern throughout development, and in rana per ... | 1988 | 3410290 |
| seasonal changes in thyroid activity in male and female frog, rana perezi. | plasma t3 and t4 levels, and thyroid free (f) and bound (b) thyroid hormones contents, were determined by radioimmunoassay in adult male and female rana perezi over 1 year. plasma t3 levels show a significant seasonal cycle in both male and female frogs, increasing from january to peak in july (71-74 pg/ml) to decrease in august-october. plasma t4 concentrations also varied seasonally, and sex differences were apparent. basal t4 levels from the end of summer to the end of winter and higher value ... | 1995 | 7713385 |
| ontogeny of ocular serotonin n-acetyltransferase activity daily rhythm in four anuran species. | the profile of daily ocular serotonin n-acetyltransferase (nat) rhythm has been examined during the development of four anuran amphibians in different environments and of varying phylogenetic origins: xenopus laevis, discoglossus pictus, rana perezi, and bufo calamita. a significant day/night rhythm of ocular nat with the acrophase at midnight was first detected at stages 43/44 and 25 in x. laevis and r. perezi, respectively. total enzymatic activity increased with body weight throughout develop ... | 1994 | 7926643 |
| occurrence of salmonella in cold-blooded animals in gran canaria, canary islands, spain. | the occurrence of salmonella in endemic and subendemic species of lizard and frog of gran canaria, gallotia stehlini and rana perezi, as well as captive reptiles from other regions of the world was investigated. the occurrence of salmonella was statistically higher in endemic and subendemic species than in captive animals (p < 0.001). seventy strains of salmonella were isolated. s. berta and s. gran canaria were the most frequently isolated serotypes. the study of salmonella in gall-bladder cont ... | 1995 | 8572675 |
| histology of the mucosa of the oesophagogastric junction and the stomach in adult rana perezi. | the histological structure of the frog digestive mucosa changes at the oesophagogastric junction. the pseudostratified ciliated mucosal epithelium of oesophageal type changes to a simple mucus-secreting epithelium of gastric type. the glands straighten and the muscularis mucosae develops as a complete layer. the muscularis increases in thickness. unlike the mammalian stomach, in the frog the surface of the plicae forms convoluted ridges that delimit furrow-shaped pits. two types of gastric gland ... | 1996 | 8621343 |
| anuran dorsal column nucleus: organization, immunohistochemical characterization, and fiber connections in rana perezi and xenopus laevis. | as part of a research program on the evolution of somatosensory systems in vertebrates, the dorsal column nucleus (dcn) was studied with (immuno)histochemical and tract-tracing techniques in anurans (the large green frog, rana perezi, and the clawed toad, xenopus laevis). the anuran dcn contains some nicotinamide adenine dinucleotide phosphate diaphorase-positive neurons, very little calbindin d-28k, and a distinct parvalbumin-positive cell population. the anuran dcn is innervated by primary and ... | 1995 | 8642070 |
| daily changes in thyroid activity in the frog rana perezi: variation with season. | plasma triiodothyronine (t3) and thyroxine (t4) levels, as well as thyroid free (f) and bound (b) thyroid hormones (th) content, were determined by radioimmunoassay (ria) in adult rana perezi frogs during a 24 h cycle in winter, spring, summer, and autumn. significant daily changes in plasma t3 levels were present in all the seasons except for winter, being the lowest values observed during the scotophase. in contrast, plasma t4 only showed significant changes in spring, following a similar patt ... | 1996 | 8689532 |
| basal ganglia organization in amphibians: efferent connections of the striatum and the nucleus accumbens. | as a further step in unraveling the organization of the basal ganglia of amphibians, the efferent connections of the striatum and the nucleus accumbens have been studied in the brains of the anurans, rana perezi and xenopus laevis, and the urodele, pleurodeles waltl, by using biotinylated or fluorescent dextran amines as anterograde tracers. a common pattern of efferent connections was observed in both groups of amphibians, but those in the anurans were more elaborate. striatal efferent fibers w ... | 1997 | 9073081 |
| basal ganglia organization in amphibians: afferent connections to the striatum and the nucleus accumbens. | as part of a research program to determine if the organization of basal ganglia (bg) of amphibians is homologous to that of amniotes, the afferent connections of the bg in the anurans xenopus laevis and rana perezi and the urodele pleurodeles waltl were investigated with sensitive tract-tracing techniques. hodological evidence is presented that supports a division of the amphibian bg into a nucleus accumbens and a striatum. both structures have inputs in common from the olfactory bulb, medial pa ... | 1997 | 9120053 |
| basal ganglia organization in amphibians: catecholaminergic innervation of the striatum and the nucleus accumbens. | the aim of the present study was to determine the origin of the catecholaminergic inputs to the telencephalic basal ganglia of amphibians. for that purpose, retrograde tracing techniques were combined with tyrosine hydroxylase immunohistochemistry in the anurans xenopus laevis and rana perezi and the urodele pleurodeles waltl. in all three species studied, a topographically organized dopaminergic projection was identified arising from the posterior tubercle/mesencephalic tegmentum and terminatin ... | 1997 | 9120054 |
| spinal ascending pathways in amphibians: cells of origin and main targets. | as part of a research program on the evolution of somatosensory systems in vertebrates, the various components of ascending spinal projections were studied with in vivo and in vitro tract-tracing techniques in representative species of amphibians (the large green frog, rana perezi, the clawed toad, xenopus laevis and the ribbed newt, pleurodeles waltl). three main ascending sensory channels, each with largely separate targets, were demonstrated: 1. ascending projections via the dorsal funiculus ... | 1997 | 9120061 |
| distribution of choline acetyltransferase immunoreactivity in the brain of anuran (rana perezi, xenopus laevis) and urodele (pleurodeles waltl) amphibians. | because our knowledge of cholinergic systems in the brains of amphibians is limited, the present study aimed to provide detailed information on the distribution of cholinergic cell bodies and fibers as revealed by immunohistochemistry with antibodies directed against the enzyme choline acetyltransferase (chat). to determine general and derived features of the cholinergic systems within the class of amphibia, both anuran (rana perezi, xenopus laevis) and urodele (pleurodeles waltl) amphibians wer ... | 1997 | 9184996 |
| membrane currents in immature oocytes of the rana perezi frog. | immature oocytes of the rana perezi frog were studied electrophysiologically to see if some of the unusual ionic channels found in xenopus oocytes were also expressed in these cells. growing oocytes showed a fairly linear current/voltage relationship (from -200 to +60 mv), whereas fully grown cells had several voltage-dependent conductances. depolarizing pulses elicited a potassium current blocked by tetraethylammonium (tea) and two kinetically different ca2+-dependent cl- currents (icl(ca)), bo ... | 1997 | 9211807 |
| changes in thyroid hormone concentrations and total contents through ontogeny in three anuran species: evidence for daily cycles. | three anuran species (rana perezi, xenopus laevis, and bufo calamita) of different phylogenetic origins and ecological habitats have been studied during ontogeny with respect to day/night changes in whole-body concentrations and total content of extrathyroidal thyroxine (t4) and triiodothyronine (t3). there were no significant day/night changes in thyroid hormones (th) during embryonic stages. daily cycles in th with higher nocturnal values appeared during premetamorphosis in r. perezi and x. la ... | 1997 | 9245532 |
| alcohol dehydrogenases in xenopus development: conserved expression of adh1 and adh4 in epithelial retinoid target tissues. | mammalian alcohol dehydrogenases adh1 (class i adh) and adh4 (class iv adh) function as retinol dehydrogenases contributing to the synthesis of retinoic acid, the active form of vitamin a involved in growth and development. xenopus laevis adh1 and adh4 genes were isolated using polymerase chain reaction primers corresponding to conserved motifs of vertebrate adhs. the predicted amino acid sequence of xenopus adh1 was clearly found to be an ortholog of adh1 from the related amphibian rana perezi. ... | 1998 | 9825862 |
| cholinergic and catecholaminergic neurons relay striatal information to the optic tectum in amphibians. | in the amphibians rana perezi and xenopus laevis, the involvement of cholinergic and catecholaminergic neurons in the relay of basal ganglia inputs to the tectum was investigated. tract-tracing experiments, in which anterograde tracers were applied to the basal ganglia and retrograde tracers to the optic tectum, were combined with immunohistochemistry for choline acetyltransferase and tyrosine hydroxylase. the results of these experiments suggest that dopaminergic neurons of the suprachiasmatic ... | 1999 | 10342448 |
| structural and enzymatic properties of a gastric nadp(h)- dependent and retinal-active alcohol dehydrogenase. | a class iv-type, gastric alcohol dehydrogenase (adh) has been purified from frog (rana perezi) tissues, meaning detection of this enzyme type also in nonmammalian vertebrates. however, the protein is unique among vertebrate adhs thus far characterized in having preference for nadp(+) rather than nad(+). similarly, it deviates structurally from other class iv adhs and has a phylogenetic tree position outside that of the conventional class iv cluster. the nadp(+) preference is structurally correla ... | 1999 | 10473548 |
| patterns of calretinin, calbindin, and tyrosine-hydroxylase expression are consistent with the prosomeric map of the frog diencephalon. | this paper re-examines a previously published segmental map of the frog diencephalon (puelles et al. [1996] brain behav.evol. 47:279-310) by means of immunocytochemical mapping of calretinin, calbindin, and tyrosine hydroxylase. the distribution of neuronal populations, axon tracts, and neuropils immunoreactive for these markers was studied in adult specimens of rana perezi and xenopus laevis sectioned sagittally or horizontally. emphasis was placed on study of the relationship of observed chemo ... | 2000 | 10717642 |
| the subcommissural organ of the frog rana perezi is innervated by nerve fibres containing gaba. | the innervation of the frog subcommissural organ was studied by light-microscopic and ultrastructural immunocytochemistry using antisera against serotonin, noradrenaline, dopamine, gamma-aminobutyric acid (gaba), glutamic acid decarboxylase, different gaba receptor subunits and bovine reissner's fibre material (afru). in the proximity of the organ, serotonin- and noradrenaline-containing fibres were rare whereas dopamine-immunoreactive fibres were more numerous. many gaba- and glutamic acid deca ... | 2000 | 10741466 |
| neural input and neural control of the subcommissural organ. | the neural control of the subcommissural organ (sco) has been partially characterized. the best known input is an important serotonergic innervation in the sco of several mammals. in the rat, this innervation comes from raphe nuclei and appears to exert an inhibitory effect on the sco activity. a gabaergic innervation has also been shown in the sco of the rat and frog rana perezi. in the rat, gaba and the enzyme glutamate decarboxylase are involved in the sco innervation. gaba is taken up by som ... | 2001 | 11241862 |
| distribution of adrenomedullin-like immunoreactivity in the central nervous system of the frog. | adrenomedullin (am) is a recently discovered peptide widely distributed in the mammalian brain. by using an antiserum specific for human am, we have analyzed the localization of am-like immunoreactivity in the brain and spinal cord of the anuran amphibian rana perezi. cell bodies immunoreactive (ami) for am were located in the dorsal, lateral and medial pallial regions, diagonal band of broca, medial septum, and above and rostral to the anterior commissure. a large population of ami neurons was ... | 2001 | 11312053 |
| descending supraspinal pathways in amphibians. i. a dextran amine tracing study of their cells of origin. | the present study is the first of a series on descending supraspinal pathways in amphibians in which hodologic and developmental aspects are studied. representative species of anurans (the green frog, rana perezi, and the clawed toad, xenopus laevis), urodeles (the iberian ribbed newt, pleurodeles waltl), and gymnophionans (the mexican caecilian, dermophis mexicanus) have been used. by means of retrograde tracing with dextran amines, previous data in anurans were largely confirmed and extended, ... | 2001 | 11331524 |
| descending supraspinal pathways in amphibians. ii. distribution and origin of the catecholaminergic innervation of the spinal cord. | immunohistochemical studies with antibodies against tyrosine hydroxylase, dopamine, and noradrenaline have revealed that the spinal cord of anuran, urodele, and gymnophionan (apodan) amphibians is abundantly innervated by catecholaminergic (ca) fibers and terminals. because intraspinal cells occur in all three orders of amphibians ca, it is unclear to what extent the ca innervation of the spinal cord is of supraspinal origin. in a previous study, we showed that many cell groups throughout the fo ... | 2001 | 11331525 |
| comparative analysis of adrenomedullin-like immunoreactivity in the hypothalamus of amphibians. | adrenomedullin (am) is a novel neuropeptide with special significance in the mammalian hypothalamo-hypophysial axis. by using an antiserum specific for human am, we have studied the localization of am-like immunoreactive (ami) cell bodies and fibers in the hypothalamus and hypophysis of the amphibians rana perezi (anuran), pleurodeles waltl (urodele), and dermophis mexicanus (gymnophionan). distinct ami cell groups were found for each species. in the anuran, six cell groups were localized in the ... | 2001 | 11458400 |
| origin and development of descending catecholaminergic pathways to the spinal cord in amphibians. | the origin and development of the supraspinal catecholaminergic (ca) innervation of the spinal cord was studied in representative species of the three amphibian orders (anura: xenopus laevis and rana perezi; urodela: pleurodeles waltl; gymnophiona: dermophis mexicanus). using retrograde dextran amine tracing in combination with tyrosine hydroxylase (th)-immunohistochemistry, we showed that only four brain centers contribute to the ca innervation of the adult spinal cord: (1) the ventrolateral co ... | 2002 | 11922982 |
| crystallization and preliminary x-ray analysis of nadp(h)-dependent alcohol dehydrogenases from saccharomyces cerevisiae and rana perezi. | different crystal forms diffracting to high resolution have been obtained for two nadp(h)-dependent alcohol dehydrogenases, members of the medium-chain dehydrogenase/reductase superfamily: scadhvi from saccharomyces cerevisiae and adh8 from rana perezi. scadhvi is a broad-specificity enzyme, with a sequence identity lower than 25% with respect to all other adhs of known structure. the best crystals of scadhvi diffracted beyond 2.8 a resolution and belonged to the trigonal space group p3(1)21 (or ... | 2003 | 12554944 |
| comparative analysis of neuropeptide ff-like immunoreactivity in the brain of anuran (rana perezi, xenopus laevis) and urodele (pleurodeles waltl) amphibians. | the neuropeptide ff (npff) is a member of the rfamide related peptides (farps) that share the dipeptide arg-phe-nh2 at their c-terminal. it was originally isolated from bovine brain and its wide distribution has been demonstrated in the brain of several mammalian species. by means of an npff antiserum we have investigated the distribution pattern of npff-like immunoreactive cells and fibers in the brain of anuran and urodele amphibians. in both amphibian orders, the most conspicuous labeled cell ... | 2003 | 12573459 |
| hodological characterization of the medial amygdala in anuran amphibians. | early studies in anuran amphibians defined the amygdala as a single unit that only later could be subdivided into medial and lateral parts with the achievement of sensitive immunohistochemical and tracing techniques. however, the terminology used was often misleading when comparing with "homologous" amygdaloid nuclei in amniotes. recently, the basal telencephalon of anurans has been demonstrated to be more complex than previously thought, and distinct amygdaloid nuclei were proposed on the basis ... | 2003 | 14556296 |
| factors affecting the organochlorine pollutant load in biota of a rice field ecosystem (ebro delta, ne spain). | the concentrations of pcbs, ddts, hchs, hcb and ocs were determined in sediments and associated biota, both invertebrates (physella acuta, hirudo medicinalis, chironomid larvae, hydrous pistaceus, helochares lividus) and vertebrates (rana perezi), in a temporary aquatic system, a rice field in the ebro delta (ne spain). the qualitative and quantitative distribution of organochlorine compounds in sediments and aquatic biota has been explained by two mechanisms: equilibrium partitioning and/or bio ... | 2004 | 15006509 |
| localization and connectivity of the lateral amygdala in anuran amphibians. | on the basis of chemoarchitecture and gene expression patterns in the amphibian amygdaloid complex, new subdivisions have been proposed and compared with their counterparts in amniotes. thus, a portion of the ventral pallium of anurans has been tentatively named "lateral amygdala" (la) and compared with the basolateral complex of mammals. to strengthen the putative homology, we have analyzed the pattern of afferent and efferent connections of the la in the anurans rana perezi and xenopus laevis. ... | 2004 | 15452828 |
| sandwich immunoassay for determination of vitellogenin in golden grey mullet (liza aurata) serum as a field exposure biomarker. | vitellogenin (vtg) is a protein produced in the liver of oviparous animals in response to oestrogens. abnormal production of vtg by males, therefore, is used as a biological indicator of exposure to xeno-oestrogens. in this study, a sandwich-elisa for measuring vtg in liza aurata (golden grey mullet) was developed and validated. plasma vtg was purified from 17beta-oestradiol-injected immature individuals of mullet, by size-exclusion and ion-exchange chromatography. polyclonal antibodies against ... | 2005 | 15756602 |
| lateral and medial amygdala of anuran amphibians and their relation to olfactory and vomeronasal information. | the amygdala of anurans is currently considered as a complex of nuclei that share many features with their counterparts in amniotes. in the present study, the subdivisions of the amygdala that are directly related to olfactory and vomeronasal information, were investigated in the anurans rana perezi and xenopus laevis. in particular, the connectivity of the main and accessory olfactory bulbs and their related amygdaloid nuclei was studied by means of in vivo and in vitro tract-tracing with dextr ... | 2005 | 16144609 |
| colocalization of nitric oxide synthase and monoamines in neurons of the amphibian brain. | by means of double immunohistofluorescence techniques, we have investigated the colocalization of nitric oxide synthase and tyrosine hydroxylase (th) or serotonin (5-ht) in the central nervous system of the anurans rana perezi and xenopus laevis and the urodele pleurodeles waltl. a wide codistribution of neuronal populations, expressing these markers, was found throughout the brain and spinal cord. in contrast, colocalization of these markers was rather restricted. only in the caudal portion of ... | 2005 | 16144649 |
| behavioral disturbances and hair cell loss in the inner ear following nitrile exposure in mice, guinea pigs, and frogs. | several nitriles have been demonstrated to cause hair cell loss in the inner ear of the rat, but the susceptibility of other species to this toxic effect has not been investigated. adult male swiss mice were administered (po) control vehicle, cis-crotononitrile (2.75 mmol/kg), or 3,3'-iminodipropionitrile (idpn, at 8, 16, and 24 mmol/kg), and the changes in vestibular function were assessed by behavioral endpoints. in addition, surface preparations of the vestibular sensory epithelia were examin ... | 2007 | 17159233 |
| combined exposure to ambient uvb radiation and nitrite negatively affects survival of amphibian early life stages. | many aquatic species are sensitive to ambient levels of ultraviolet-b radiation (uvb) and chemical fertilizers. however, recent studies indicate that the interaction among multiple stressors acting simultaneously could be contributing to the population declines of some animal species. therefore, we tested the potential synergistic effects between ambient levels of uvb and a contaminant, sodium nitrite in the larvae of two amphibian species, the common european toad bufo bufo and the iberian gree ... | 2007 | 17628639 |
| conserved pattern of otp-positive cells in the paraventricular nucleus and other hypothalamic sites of tetrapods. | the paraventricular nucleus complex (pa) is a component of central neural circuitry that regulates several homeostatic variables. the paraventricular nucleus is composed of magnocellular neurons that project to the posterior pituitary and parvicellular neurons that project to numerous sites in the central nervous system. according to the revised prosomeric model, the paraventricular nucleus is located caudal to the eye stalk along the rostrocaudal dimension of the dorsal hypothalamic alar plate. ... | 2008 | 18331876 |
| intraspecific and interspecific tolerance to copper sulphate in five iberian amphibian species at two developmental stages. | intraspecific and interspecific variations have been observed across many taxa with respect to resistance to natural environmental stressors. it has already been well documented that amphibians are sensitive to habitat degradation and are regarded as bioindicators of aquatic and agricultural ecosystems. in southern spain, different toxic substances, including copper sulphate, which is used to control cycloconium oleaginum (fungi, ascomycota, venturiaceae) during spring and autumn, are used in in ... | 2010 | 20162266 |
| immunohistochemical localization of darpp-32 in the brain and spinal cord of anuran amphibians and its relation with the catecholaminergic system. | the relationship between dopaminergic neuronal structures and dopaminoceptive structures in the amphibian brain and spinal cord are assessed by means of single and double immunohistochemical techniques with antibodies directed against darpp-32 (a phosphoprotein related to the dopamine d(1)-receptor) and tyrosine hydroxylase (th) applied to the brain of the anurans rana perezi and xenopus laevis. the darpp-32 antibody yielded a well-differentiated pattern of staining in the brain of these anurans ... | 2010 | 20887782 |
| antioxidant response and metal accumulation in tissues of iberian green frogs (pelophylax perezi) inhabiting a deactivated uranium mine. | human mining activities tend often to generate greatly impacted areas which remain contaminated for long periods of time, giving rise to extreme habitats. mining sites are usually characterized for the production of metal rich effluents with very low ph. in this work we analyzed physical and chemical parameters of water from a deactivated uranium mine pond (m) and a reference site (ref) as well as their metal content. furthermore, we determined and compared metal accumulation in liver, kidney, b ... | 2011 | 21516444 |
| different sensitivity to the dexamethasone treatment of the lymphoid organs of rana perezi in two different seasons. | adult female frogs (rana perezi) have been used to analyze structural and morphometrical changes which affect lymphoid organs after treatment with a single dose of dexamethasone (dx). special attention was given to the distinct sensitivity observed during two different periods of the year. morphological differences were found between adult control frogs sacrificed in november and february. in february, frogs showed degenerated thymic reticular epithelial cells but lesser numbers of cortical pycn ... | 2009 | 2767310 |
| testing procedures for the determination of several biomarkers in different species, for environmental assessment of pollution. | antioxidant defences are the primary mechanisms by which organisms compensate oxidative damage caused by contact with several types of substances prone to establish oxidative cycles. biomarkers are one of the most useful tools to assess effects consequent to environmental exposure to a large number of xenobiotics. however, the use of biomarkers requires previous standardization of enzymatic protocols in order to guarantee accuracy and relevance of obtained results. this article describes standar ... | 2010 | 20589292 |
| light-dependent magnetic compass in iberian green frog tadpoles. | here, we provide evidence for a wavelength-dependent effect of light on magnetic compass orientation in pelophylax perezi (order anura), similar to that observed in rana catesbeiana (order anura) and notophthalmus viridescens (order urodela), and confirm for the first time in an anuran amphibian that a 90° shift in the direction of magnetic compass orientation under long-wavelength light (≥ 500 nm) is due to a direct effect of light on the underlying magnetoreception mechanism. although magnetic ... | 2010 | 20978882 |
| reliable effective number of breeders/adult census size ratios in seasonal-breeding species: opportunity for integrative demographic inferences based on capture-mark-recapture data and multilocus genotypes. | the ratio of the effective number of breeders (nb) to the adult census size (na), nb/na, approximates the departure from the standard capacity of a population to maintain genetic diversity in one reproductive season. this information is relevant for assessing population status, understanding evolutionary processes operating at local scales, and unraveling how life-history traits affect these processes. however, our knowledge on nb/na ratios in nature is limited because estimation of both paramet ... | 2017 | 29238556 |
| effects of sample size and full sibs on genetic diversity characterization: a case study of three syntopic iberian pond-breeding amphibians. | accurate characterization of genetic diversity is essential for understanding population demography, predicting future trends and implementing efficient conservation policies. for that purpose, molecular markers are routinely developed for nonmodel species, but key questions regarding sampling design, such as calculation of minimum sample sizes or the effect of relatives in the sample, are often neglected. we used accumulation curves and sibship analyses to explore how these 2 factors affect mar ... | 2017 | 28444211 |
| plastic changes in tadpole trophic ecology revealed by stable isotope analysis. | amphibian larvae constitute a large fraction of the biomass of wetlands and play important roles in their energy flux and nutrient cycling. interactions with predators and competitors affect their abundance but also their foraging behaviour, potentially leading to non-consumptive cascading effects on the whole trophic web. we experimentally tested for plastic changes in larval trophic ecology of two anuran species in response to competitors and the non-lethal presence of native and non-native pr ... | 2013 | 22915331 |
| inter- and intra-specific variation on sensitivity of larval amphibians to nitrite. | several authors have suggested that nitrogen-based fertilizers may be contributing to the global amphibian decline. we have studied the impact of sodium nitrite on early aquatic stages of epidalea calamita, pelophylax perezi and hyla meridionalis larvae from doñana national park (coastal wetland) and p. perezi from gredos mountain (high mountain ponds), exposed during 10 to 16 days. after 8 days of exposure all p. perezi larvae from doñana presented 100% mortality at 5 mg l(-1)n-no2(-) while e. ... | 2008 | 18023843 |
| histochemical determination of muscle fiber types in locomotor muscles of anuran amphibians. | 1. a histochemical study using myosin atpase, succinate dehydrogenase and alpha-glycerophosphate dehydrogenase reactions and a morphometric analysis with image analyser, was carried out in sartorius and gastrocnemius muscles of two anuran species, rana perezi and bufo calamita, that show different locomotor activities. 2. four types of muscle fiber were found. there were interspecific variations in their proportions, with a predominance of oxidative muscle fibers in bufo calamita. 3. these resul ... | 1991 | 1714364 |
| geologically dated sea barriers calibrate a protein clock for aegean water frogs. | reliable estimates of phylogenetic relationships and divergence times are a crucial requirement for many evolutionary studies, but are usually difficult because fossils are scarce and their interpretation is often uncertain. frogs are fresh water animals that generally are unable to cross salt water barriers (their skin is readily permeable to both salt and water). the geologically determined ages of salt water barriers that isolate related frog populations thus provide an independent measure of ... | 1996 | 28565728 |
| biochemical variation in the rana esculenta complex: a new hybrid form related to rana perezi and rana ridibunda. | investigations of the green frogs from western europe for electrophoretic variations at 4 enzyme loci demonstrated a new form which must be considered as a hybrid between rana ridibunda and r. perezi. biochemical evidence supports the hypothesis that its reproduction is hybridogenetic, as it is for r. esculenta. | 1977 | 304017 |
| effects of the herbicides linuron and s-metolachlor on perez's frog embryos. | presence of pesticides in the environment and their possible effects on aquatic organisms are of great concern worldwide. the extensive use of herbicides in agricultural areas are one of the factors contributing to the known decline of amphibian populations. thus, as non-target species, amphibians can be exposed in early life stages to herbicides in aquatic systems. in this context, this study aims to evaluate effects of increasing concentrations of two maize herbicides, linuron and s-metolachlo ... | 0 | 29241134 |
| effects of 4-mbc and triclosan in embryos of the frog pelophylax perezi. | the widespread and increasing use of personal care products (pcps) have led to environmental contamination by substances included in these products. these substances have been detected in aquatic compartments and shown to cause adverse effects on non-target aquatic organisms. in this work toxicity of the antimicrobial triclosan (tcs) and of the uv-filter 3-(4-methylbenzylidene) camphor (4-mbc) was assessed in the embryos of perez' frog pelophylax perezi. lethal and sub-lethal parameters were eva ... | 2017 | 28334672 |
| diversity of cutaneous microbiome of pelophylax perezi populations inhabiting different environments. | potential synergetic interaction between chemicals, climate change and the emergence of opportunistic diseases is of utmost concern within the amphibian decline scenario. understand the structure and dynamic of this microbiome and how environmental stressors act on this community is a priority. the present study aimed to: i) characterize the skin microbiome of pelophylax perezi frog by looking for variations between populations in reference and under stress conditions (one metal contaminated and ... | 2016 | 27522290 |
| impact of the insecticide alphacypermetrine and herbicide oxadiazon, used singly or in combination, on the most abundant frog in french rice fields, pelophylax perezi. | the potential impact of agricultural pesticides is a major concern with regard to biodiversity conservation. pesticides are considered as one of the main causes of the worldwide decline of amphibians. they are rarely used singly, but their cumulative impact and interaction are often neglected, as is the importance of the age or stage of the animal on which the impact of the molecules is assessed. we therefore tested the potential cumulative impact of the only authorized insecticide (alphacyperme ... | 2016 | 27107241 |
| rapid evolution of constitutive and inducible defenses against an invasive predator. | invasive alien predators can impose strong selection on native prey populations and induce rapid evolutionary change in the invaded communities. however, studies on evolutionary responses to invasive predators are often complicated by the lack of replicate populations differing in coexistence time with the predator, which would allow the determination of how prey traits change during the invasion. the red swamp crayfish procambarus clarkii has invaded many freshwater areas worldwide, with negati ... | 2014 | 25039217 |
| molecular survey of parasites in introduced pelophylax perezi (ranidae) water frogs in the azores. | water frogs, pelophylax perezi, that are introduced in the azores, were screened for parasites using pcr primers known to amplify apicomplexa parasites, and using nematode-specific primers. with the former, three different organisms were detected: hepatozoon, a trichodinid protozoan ciliate and a possible stramenopile. using the latter set of primers, a single unknown spirurid nematode was also detected. phylogenetic analyses indicate that hepatozoon detected within amphibian hosts appear to for ... | 2013 | 24338327 |
| contrasting effects of nitrogenous pollution on fitness and swimming performance of iberian waterfrog, pelophylax perezi (seoane, 1885), larvae in mesocosms and field enclosures. | amphibians are declining worldwide and pollutants have been implicated as a major contributor to these declines. to understand these declines, many studies have assessed the impact of pollutants on amphibian behaviour. however, information regarding their effect on locomotor abilities, as well as the intra-specific variation of the tolerance to pollutants, is extremely rare. further, the majority of studies examining the impact of pollutants on amphibians have been conducted in simplified labora ... | 2014 | 24296112 |
| copper-driven avoidance and mortality in temperate and tropical tadpoles. | amphibians have experienced an accentuated population decline in the whole world due to many factors, one of them being anthropogenic contamination. the present study aimed to assess the potential effect of copper, as a worldwide and reference contaminant, on the immediate decline of exposed population due to avoidance and mortality responses in tadpoles of three species of amphibians across climatic zones: a south american species, leptodactylus latrans, a north american species, lithobates cat ... | 2014 | 24291082 |
| call transmission efficiency in native and invasive anurans: competing hypotheses of divergence in acoustic signals. | invasive species are a leading cause of the current biodiversity decline, and hence examining the major traits favouring invasion is a key and long-standing goal of invasion biology. despite the prominent role of the advertisement calls in sexual selection and reproduction, very little attention has been paid to the features of acoustic communication of invasive species in nonindigenous habitats and their potential impacts on native species. here we compare for the first time the transmission ef ... | 2013 | 24155940 |
| salinity and copper interactive effects on perez's frog pelophylax perezi. | the present study was intended to assess the influence of salinity on the effects of copper on 2 life stages of pelophylax perezi. single and combined effects of salinity (nacl) and cu on survival, malformations, body length, and biochemical markers (catalase [cat], cholinesterases, lactate dehidrogenase [ldh], and glutathione s-transferase) of individuals were evaluated in a multifactorial design. two experiments were performed, 1 with embryos and the other with tadpoles. each of these life sta ... | 2013 | 23625701 |
| influence of low levels of water salinity on toxicity of nitrite to anuran larvae. | reactive nitrogen compounds such as nitrite (no2(-)) are highly toxic to aquatic animals and are partly responsible for the global decline of amphibians. on some fish and caudata amphibian species low levels of sodium chloride significantly reduce the toxicity of nitrite. however, the nitrite-salinity interaction has not been properly studied in anuran amphibians. to verify if chloride (cl(-)) attenuates no2(-) toxicity, eggs and larvae of three anuran species were subjected to a series of no2(- ... | 2013 | 23466091 |
| evaluation of growth, biochemical and bioaccumulation parameters in pelophylax perezi tadpoles, following an in-situ acute exposure to three different effluent ponds from a uranium mine. | mining activities invariably produce metal contaminated effluents. depending on factors such as ph and metal concentration the toxicity of the effluent may vary. to assess the effects of three characteristically different effluent ponds from a deactivated uranium mine, with toxicologically relevant data, an in situ exposure with pelophylax perezi tadpoles, was conducted. tadpoles were exposed to the three effluent ponds, ranked by increasing order of metals concentrations (ref, m1, m2). survival ... | 2013 | 23348721 |
| biochemical and metabolic effects of a short-term exposure to nanoparticles of titanium silicate in tadpoles of pelophylax perezi (seoane). | this study aimed to evaluate sublethal effects of a short-term exposure (96 h) to titanium silicate nanoparticles (tisio(4)-np) on pelophylax perezi tadpoles. tadpoles were exposed to five concentrations of tisio(4)-np (8.2, 10.2, 12.8, 16 and 20 mg/l) plus a control. effect criteria were: mortality, cholinesterases, glutathione s-transferases, lactate dehydrogenase, and catalase activities, and alanine and lactate contents. light scattering was used for physical characterization of tisio(4)-np ... | 2013 | 23314277 |
| differential gene expression in iberian green frogs (pelophylax perezi) inhabiting a deactivated uranium mine. | iberian green frogs (pelophylax perezi) were found inhabiting a deactivated uranium mine, especially an effluent pond, seriously contaminated with metals and radionuclides. these animals were previously assessed for oxidative stress parameters and did not revealed significant alterations. in order to better understand which mechanisms may be involved in the ability to withstand permanent contamination gene expression analysis was performed in the liver, through suppression subtractive hybridizat ... | 2013 | 23146668 |
| adaptive forgetting in iberian green frog tadpoles (pelophylax perezi): learned irrelevance and latent inhibition may avoid predator misidentification. | predator recognition often requires learning by prey individuals. iberian green frog tadpoles (pelophylax perezi) have the ability to learn to recognize new potential predators when their chemical cues are found paired with conspecific alarm cues. however, a random pairing of alarm cues and chemical stimuli of a nonpredator might later induce costly antipredator responses to nondangerous species. here, we studied the potential existence in this frog species of two phenomena (learned irrelevance ... | 2013 | 22866772 |
| behavioral responses of the iberian waterfrog, pelophylax perezi (seoane, 1885), to three nitrogenous compounds in laboratory conditions. | several studies have assessed the effects of nitrogenous compounds on amphibian behavior. however, few have focused on the effects of their combination with other stressors or on the variation of the response to pollutants among populations. we analyzed the effect of nitrogenous compounds (nh(4)(+); no(2)(-); no(3)(-), both alone and in combination) on larval behavior (activity level and location in the water column) in four populations of pelophylax perezi naturally exposed to different levels ... | 2011 | 21512748 |
| invasive predatory crayfish do not trigger inducible defences in tadpoles. | invasive species cause deep impacts on ecosystems worldwide, contributing to the decline and extinction of indigenous species. effective defences against native biological threats in indigenous species, whether structural or inducible, often seem inoperative against invasive species. here, we show that tadpoles of the iberian green frog detect chemical cues from indigenous predators (dragonfly nymphs) and respond by reducing their activity and developing an efficient defensive morphology against ... | 2011 | 21450734 |
| adaptation to osmotic stress provides protection against ammonium nitrate in pelophylax perezi embryos. | the negative effects of pollution on amphibians are especially high when animals are additionally stressed by other environmental factors such as water salinity. however, the stress provoked by salinity may vary among populations because of adaptation processes. we tested the combined effect of a common fertilizer, ammonium nitrate (0-90.3 mg n-no3nh4/l), and water salinity (0-2 per thousand) on embryos of two pelophylax perezi populations from ponds with different salinity concentrations. embry ... | 2010 | 19800720 |
| populational divergence in the impact of three nitrogenous compounds and their combination on larvae of the frog pelophylax perezi (seoane, 1885). | pollution by nitrogenous compounds is a putative stressful factor that may be causally linked to the decline of amphibians. one way to understand the potentially detrimental consequences of eutrophication on amphibian populations is to investigate variation among populations differing in exposure to nitrogen, this variation potentially indicating evolutionary potential to cope with this stressor. we have examined the effect of nitrogenous compounds (nh(4)(+); no(2)(-); no(3)(-), both alone and i ... | 2009 | 19540549 |
| learning, memorizing and apparent forgetting of chemical cues from new predators by iberian green frog tadpoles. | many antipredator adaptations are induced by the prey's ability to recognize chemical cues from predators. however, predator recognition often requires learning by prey individuals. iberian green frog tadpoles (pelophylax perezi) have the ability to learn new potential predators. here, we tested the memory capabilities of iberian green frog tadpoles. we conditioned tadpoles with chemicals cues from a non-predatory fish in conjunction with conspecific alarm cues, and examined whether tadpoles ret ... | 2009 | 19449191 |
| histopathological changes and erythrocytic nuclear abnormalities in iberian green frogs (rana perezi seoane) from a uranium mine pond. | in spite of their sensitivity to anthropogenic stressors, adults of rana perezi seoane were found inhabiting effluent ponds from a uranium mine. due to the presence of such organisms in this environment, it becomes of paramount importance to assess the damages induced by local contamination on these aquatic vertebrates, in order to integrate this information on a site-specific risk assessment that is being carried out in the area. to attain this purpose an ethically and statistically acceptable ... | 2009 | 18541315 |
| effects of a uranium mine effluent in the early-life stages of rana perezi seoane. | amphibians have been reported as sensitive organisms whose survival has been impaired by several environmental factors. nevertheless, sometimes amphibians are found inhabiting extreme environments. thus, in order to perceive how iberian green frogs (rana perezi seoane) are able to survive in the ponds of a uranium mine (central portugal) this study aimed to assess the ecotoxicological effects promoted by the mine effluent in the early-life stages of this species. to attain this objective, eggs ( ... | 2008 | 18538823 |
| calbindin-d28k and calretinin as markers of retinal neurons in the anuran amphibian rana perezi. | in the present study we have analyzed the distribution of the calcium binding proteins calbindin-d28k (cb) and calretinin (cr) immunoreactive cells in the retina of the anuran rana perezi using poly- and mono-clonal antibodies that were proven to be specific in the amphibian brain, without cross-reactivity. double immunohistofluorescence techniques were used to demonstrate colocalization of both proteins in the same retinal cells. in addition, retrograde tracing experiments from the optic nerve ... | 2008 | 18331902 |
| analysis of the avoidance of nitrogen fertilizers in the water column by juvenile iberian water frog, pelophylax perezi (seoane, 1885), in laboratory conditions. | in an experiment carried out in the laboratory in beakers, the avoidance of ammonium chloride, isolated or combined with sodium nitrite and sodium nitrate, in aquatic habitat by froglets of pelophylax perezi was studied. the results obtained suggest that nitrogen polluted treatments were not avoided by froglets of the studied species. however, despite the non-avoidance of the aquatic environment as a consequence of the presence of nitrogen compounds, significant inter-individual variation in tre ... | 2008 | 18193144 |
| helminth communities of two green frogs (rana perezi and rana saharica) from both shores of the alboran sea. | the helminth communities of two populations of green frogs from both shores of the alborón sea (western mediterranean) were studied. of the 79 frogs examined for helminths, 39 individuals of the species rano saharica were collected from bob-taza (morocco), and 40 of the species rona perezi were collected from the natural park of the sierra de grazalema (spain). although the species richness of helminths was identical in the two sampled areas, the differences observed in the structure of the helm ... | 2006 | 17285849 |
| the importance of heterozygosity in a frog's life. | high genetic variability may increase metabolic efficiency and thus allows responding to environmental challenges as limits to adaptation are approached. therefore, it has been suggested that high genetic variability contributes strongly to the fitness of an individual. survival to high age may thus depend on high genetic variability, and genetically variable individuals may have a higher survival rate to high ages in comparison to less variable sympatric conspecifics. such a heterozygosity x ag ... | 2007 | 17242953 |
| basal forebrain cholinergic system of the anuran amphibian rana perezi: evidence for a shared organization pattern with amniotes. | the organization of the basal forebrain cholinergic system (bfcs) in the frog was studied by means of choline acetyltransferase (chat) immunohistochemistry. the bfcs was observed as a conspicuous cholinergic cell population extending through the diagonal band, medial septal nucleus, bed nucleus of the stria terminalis, and pallidal regions. abundant fiber labeling was also found around the labeled cell bodies. the combination of retrograde tract tracing with dextran amines and chat immunohistoch ... | 2006 | 16385484 |
| ontogeny of central melatonin receptors in tadpoles of the anuran rana perezi: modulation of dopamine release. | the objective of this work was to study melatonin receptors in the eye and the brain and their possible functionality in the ontogeny of rana perezi. the binding of 2-[(125)i]melatonin increases throughout embryonic larval development in both tissues. the most pronounced increase takes place at the end of premetamorphosis and during early prometamorphosis. this rise coincides temporarily with the appearance of the rhythmic melatonin-synthesizing capacity in the retina. in the three studied devel ... | 2005 | 16075267 |
| forebrain projections to the hypothalamus are topographically organized in anurans: conservative traits as compared with amniotes. | the organization of the forebrain in amphibians (anamniotes) is currently being re-evaluated in terms of evolution and several evidences have corroborated numerous traits shared by amphibians and amniotes, such as the organization of the basal ganglia and the amygdaloid complex. in the present study we have analysed the organization of forebrain afferent systems to the hypothalamus of the frog rana perezi. in vivo and in vitro tract-tracing techniques with dextran amines and immunohistochemistry ... | 2005 | 15869483 |
| effects of temperature on 2-[125i]-iodomelatonin binding to melatonin receptors in the neural retina of the frog rana perezi. | the present study analyzes the effect of temperature-dependent modifications on the binding of the analog 2-[125i]-melatonin to melatonin receptors in isolated neural retina membranes from the greenfrog rana perezi. association and dissociation rate constants (k+1, k-1) were exponentially increased by the assay temperature. at 15 degrees c, association and dissociation required several hours; meanwhile, at 35 degrees c, rate constants were 100- and 34-fold faster, respectively. however, the kd c ... | 2005 | 15725339 |
| 2-[125i]-melatonin binding sites in the central nervous system and neural retina of the frog rana perezi: regulation by light and temperature. | the objective of the present study is to test daily and seasonal changes in 2-[125i]-melatonin ([125i]-mel) binding in different brain areas and the retina of the frog rana perezi as well as the possible effect of light and temperature on melatonin receptors. during the day-night cycle, binding of [125i]-mel showed a clear rhythm in the optic tectum, diencephalon, telencephalon, and neural retina, the binding being higher in the light phase than in the dark phase. by contrast, melatonin receptor ... | 2004 | 15504386 |
| activation of amp-dependent protein kinase by hypoxia and hypothermia in the liver of frog rana perezi. | we have investigated different signaling molecules that could be activated by temperature acclimation and hypoxia, using an experimental approach consisting in submerging frogs in a water-filled box maintained at 2-4 degrees c at ambient oxygen levels or supplied with 98% n2:2% co2 for normoxia or hypoxia conditions, respectively. the results obtained showed no significant changes in the expression of heat shock protein 70. the phosphorylation state of amp-dependent activated protein kinase, the ... | 2004 | 15351690 |
| characterization of melatonin binding sites in the brain and retina of the frog rana perezi. | the aim of this study was to characterize 2-[125i]iodomelatonin binding sites in the neural retina and central nervous system (telencephalon, diencephalon, and optic tectum) of the anuran amphibian rana perezi. saturation and kinetic studies and pharmacological characterization revealed the existence of a unique melatonin-binding site that belongs to the mel 1 receptor subtype. the affinity of this site is similar in all tissues studied (kd, 10.5-12.8 pm), but the density varied from diencephalo ... | 2004 | 14723877 |
| complete reversal of coenzyme specificity by concerted mutation of three consecutive residues in alcohol dehydrogenase. | gastric tissues from amphibian rana perezi express the only vertebrate alcohol dehydrogenase (adh8) that is specific for nadp(h) instead of nad(h). in the crystallographic adh8-nadp+ complex, a binding pocket for the extra phosphate group of coenzyme is formed by adh8-specific residues gly223-thr224-his225, and the highly conserved leu200 and lys228. to investigate the minimal structural determinants for coenzyme specificity, several adh8 mutants involving residues 223 to 225 were engineered and ... | 2003 | 12902331 |
| distribution of adrenomedullin and proadrenomedullin n-terminal 20 peptide immunoreactivity in the pituitary gland of the frog rana perezi. | adrenomedullin (am) and proadrenomedullin n-terminal 20 peptide (pamp) are two multifunctional peptides processed from a common precursor which have been described in numerous mammalian organs, including the pituitary gland. previous studies have found am immunoreactivity in neurohypophysis nerve fibers of amphibian pituitary. in the present study, immunocytochemical and western blot analysis in the pituitary gland of the amphibian rana perezi demonstrated in the adenohypophysis both am and pamp ... | 2003 | 12899846 |
| catecholaminergic innervation of the septum in the frog: a combined immunohistochemical and tract-tracing study. | in the present study, we have investigated the distribution and the origin of the catecholaminergic innervation of the septal region in the frog rana perezi. immunohistochemistry for dopamine and two enzymes required for the synthesis of catecholamines, tyrosine hydroxylase (th) and dopamine beta-hydroxylase (dbh) revealed a complex pattern of catecholaminergic (ca) innervation in the anuran septum. dopaminergic fibers were primarily present in the dorsal portion of the lateral septum, whereas n ... | 2003 | 12483684 |
| distribution and origin of the catecholaminergic innervation in the amphibian mesencephalic tectum. | the mesencephalic tectum plays a prominent role in integrating both visual and multimodal sensory information essential for normal behavior in amphibians. activity in the mesencephalic tectum is thought to be modulated by the influence of distinct neurochemical inputs, including the catecholaminergic and the cholinergic systems. in the present study, we have investigated the distribution and the origin of the catecholaminergic innervation of the mesencephalic tectum in two amphibian species, the ... | 2013 | 12392181 |
| localization of nadph diaphorase/nitric oxide synthase and choline acetyltransferase in the spinal cord of the frog, rana perezi. | the localization of nitrergic cells and fibers and cholinergic cells has been analyzed in the spinal cord of the anuran amphibian rana perezi. histochemistry for nicotinamide adenine dinucleotide phosphate-diaphorase and nitric oxide synthase immunohistochemistry revealed a concurrent pattern of labeled structures. a large population of nitrergic spinal neurons was found from the level of the obex to the filum terminale. they are abundant in the dorsal horn and intermediate gray matter, but also ... | 2000 | 10742715 |
| melatonin synthesis in the greenfrog retina in culture: ii. dopaminergic and adrenergic control. | serotonin n-acetyltransferase (nat) activity and melatonin show a daily rhythm with high levels at night. although the rhythmic properties of nat and melatonin are similar in pineal gland and retina, great differences in the light perception and transmission mechanisms exist. we have analyzed the effects of adrenergic and dopaminergic agents on greenfrog (rana perezi) eyecup culture, in order to identify the receptors involved in the regulation of retinal melatonin synthesis. a d2-like receptor ... | 2000 | 10680577 |