Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| 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 |
| thermal sensitivity and effect of temperature acclimation on ocular serotonin n-acetyltransferase activity in rana perezi. | the thermal sensitivity and the response to thermal acclimation of the serotonin n-acetyltransferase (nat) activity in frog ocular tissue were studied. the ocular nat shows a positive thermal modulation for both cosubstrates (tryptamine and acetyl-coa). the higher nat activity in the cold-acclimated group (4 degrees c) with respect to the warm-acclimated one (24 degrees c) implies a partial thermal compensation of the enzyme. the present results suggest that frog ocular nat response to temperatu ... | 1992 | 1454214 |
| differential response of amphibian prl and tsh pituitary cells to in vitro trh treatment. | hypophysial prolactin (prl) and thyrotropin (tsh) cells of rana perezi were examined after treatment in vitro with synthetic thyrotropin-releasing hormone (trh). ultrastructural morphometry applied to prl and tsh immunoidentified cells estimated the volume density (vv) of the secretory granules (sg), rough endoplasmic reticulum (er), and golgi complex (gc) as well as the numerical density (nv) of the granules. hemipituitaries were cultured in a superfusion system with or without 100 ng trh/ml fo ... | 1992 | 1478437 |
| role of environmental temperature and photoperiod in regulation of seasonal testicular activity in the frog, rana perezi. | to analyze the role of environmental temperature and photoperiod in the regulation of the annual testicular cycle in rana perezi, we performed experiments combining high (25 +/- 1 degrees c) or low (6 +/- 1 degrees c) temperature and different photoperiod regimens (18l:6d, 12l:12d, and 6l:18d (hours light:hours dark)) during three phases of the reproductive cycle: winter stage (december) and prebreeding (february) and postbreeding (may, june) periods. low temperature and short photoperiod in win ... | 1992 | 1490253 |
| histology of the esophagus of the adult frog rana perezi (anura: ranidae). | study of the esophageal microscopic morphology of adult rana perezi by light and electron microscopy discloses some large folds throughout the esophagus that are in themselves ringed. glandular ostia open in the furrows of the luminal surface. the esophageal wall is made up of a connective adventitia rich in melanocytes, a muscular tunica, a connective and glandular subepithelial layer, and a pseudostratified ciliated epithelium. this epithelium basically consists of ciliated, goblet, basal, mic ... | 1992 | 1507236 |
| functional stages in the interrenal cells of rana perezi (anura: ranidae). | the electron density of the lipid droplets and mitochondrial matrix of the interrenal cells of rana perezi differs during the year. this makes it possible to characterize the different stages of interrenal cell activity. a droplet/mitochondria index, based on their relative size, may provide an indicator of cellular activity. | 1992 | 1588592 |
| skeletal malformations in hatchery reared rana perezi tadpoles. | skeletal malformations at metamorphosis in rana perezi tadpoles reared in culture have been studied. tadpoles were fed ten artificially compounded and fresh diets and kept at two different temperatures. animals were maintained in fiberglass tanks. bone damages are related to the nourishment with compound diets. tadpoles fed such diets showed variable percentages of scoliosis, kyphosis, luxations, and subluxations in the hind limbs, aplasia in phalanges, and wide failures of ossification. the dat ... | 1992 | 1605395 |
| 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 |
| 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 |
| characterization of serotonin n-acetyltransferase in the lateral eye of the green frog rana perezi: protective action of egta. | the kinetics of serotonin n-acetyltransferase (nat) from the lateral eye of rana perezi have been characterized. nat from ocular tissue reached maximal activity at a phosphate buffer concentration of 250 mm and a ph of 6.5. reaction linearity was highly conserved within the homogenate fraction range tested (0.033-0.33). the time course of ocular nat reaction showed a high linearity at 25 and 35 degrees c. km and vmax estimations for acetyl-coa at a 10 mm tryptamine concentration were 63.3 microm ... | 1992 | 1729403 |
| subcellular responsiveness of amphibian growth hormone cells after tsh-releasing hormone stimulation. | pituitary gh cells from adult male rana perezi frogs were investigated in vivo and in vitro after stimulation with synthetic thyrotropin-releasing hormone (trh). the volume density (vv) of the secretory granules (sg), rough endoplasmic reticulum (er), and golgi complex (gc), and the numerical density (nv) of the granules were estimated by ultrastructural morphometry. gh-producing cells were identified by the immunocytochemical colloidal-gold method, using anti-ovine-gh as primary antiserum. the ... | 1991 | 1778414 |
| 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 |
| response to pinealectomy and blinding in vitellogenic female frogs (rana perezi) subjected to high temperature in autumn. | the present experiments were carried out to investigate the effects of pinealectomy and bilateral enucleation on the ovarian activity in rana perezi frogs maintained in 12-h light--12-h dark photoperiod and 20 +/- 1 degrees c during the vitellogenetic growth in late autumn. these environmental conditions, mainly temperature, induce a gonadal and metabolic response similar to that observed in the natural habitat in summer: a marked ovarian follicular regression, a depletion of the energetic resou ... | 1990 | 2328447 |
| effects of melatonin on gonadal steroids and glucose plasma levels in frogs (rana perezi and rana temporaria). | the effect of melatonin treatment on the gonosomatic index (gsi), ovarian germinal epithelium, plasma estradiol and testosterone levels was studied in rana perezi females in december. no significant changes were observed in gsi, estradiol, and testosterone levels in melatonin treated animals when compared with saline injected controls, but the percentage of previtellogenic follicles decreased in animals treated with melatonin (100 micrograms). the effect of melatonin treatment on glucose level w ... | 1990 | 2338616 |
| an ultrastructural study of the spleen of the ranid frog rana perezi. | the spleen of rana perezi is encapsulated by connective tissue and shows by light microscopy two areas with no obvious border: the white pulp and the red pulp. the white pulp-lymphoid clusters are scattered throughout the organ and contain lymphocytes, reticular cells, and some plasma cells. the red pulp displays two different portions. the predominant region consists of reticular cells, lymphocytes, a variety of other leucocytes, and cells undergoing division. this area possibly performs a haem ... | 1990 | 2338716 |
| thymus of rana perezi: presence of interdigitating cells. | in the thymus of rana perezi, as in other anuran amphibians, there exist two different portions, cortex and medulla. in both sections epithelio-reticular cells are observed as are lymphocytes, macrophages, and granulocytes. in addition, the medulla shows cysts and secretory, myoid, and hypertrophied epithelio-reticular cells. in the cortex, plasma cells and interdigitating cells were also observed. interdigitating cells make contact with lymphocytes. this finding provides morphological support f ... | 1990 | 2366244 |
| 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 |
| 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 |
| effect of environmental temperature and photoperiod on the melatonin levels in the pineal, lateral eye, and plasma of the frog, rana perezi: importance of ocular melatonin. | day-night melatonin concentrations were studied in the pineal body, lateral eye, and plasma of the frog rana perezi in animals maintained in february and july under long (18l:6d) or short (6l:18d) photoperiod and high (25 +/- 1 degree) or low (6 +/- 1 degree) temperature in order to evaluate the influence of these environmental factors. when frogs were kept under short photoperiod and low temperature in february, no melatonin rhythm was observed in the pineal, ocular tissue, and plasma. high tem ... | 1989 | 2767408 |
| seasonal changes in the activities of glycolytic enzymes from liver and skeletal muscle of rana perezi. | glycogen phosphorylase (gp), hexokinase (hk), phosphofructokinase (pfk), pyruvate kinase (pk) and lactate dehydrogenase (ldh) activities from skeletal muscle and liver were measured in rana perezi for the four seasons of the year. skeletal muscle showed a decrease in pfk, pk and ldh activity during winter and summer. liver displayed an increase in gp activity in spring and in pk and ldh in autumn. | 1987 | 2834804 |
| thyroxin specifically stimulates anuran larvae epidermal sodium pump during metamorphosis. | 1. sodium pump, measured as k+-dependent, ouabain sensitive pnppase, but not the non-specific, ouabain insensitive pnppase, was stimulated by thyroxin in epidermis of tadpoles of rana perezi. 2. epidermal k+-pnppase of thyroxin treated tadpoles was only stimulated in those stages already showing activity and reached levels similar to adult frogs in tadpoles at metamorphic climax. | 1988 | 2907432 |
| seasonal cycles in testicular activity in the frog, rana perezi. | studies of seasonal testicular cycle based on spermatogenetic activity and direct measurement of plasma testosterone were made in male frog rana perezi obtained from its natural biotope in the iberian peninsula. testosterone plasma level was determined by radioimmunoassay and exhibited notable differences according to season: plasma testosterone was lowest (less than 0.5 ng/ml) in summer and then increased progressively to reach a peak in spring (3-4 ng/ml), coincident with mating. after spermia ... | 1989 | 2920893 |
| 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 |
| effects of dexamethasone on the lymphoid organs of rana perezi. | owing to the possible importance of steroids in the mutual neuroendocrine-immune influences found in lower vertebrates, we study the structural and morphometrical changes induced by a single dose of dexamethasone, a synthetic corticosteroid, on the lymphoid organs of the frog rana perezi. the dexamethasone treatment produces thymic involution with massive destruction of cortical lymphocytes, intense peripheral lymphopenia with lymphocyte redistribution to the bone marrow from peripheral blood an ... | 1987 | 3622888 |
| evidence for a mesolimbic pathway in anuran amphibians: a combined tract-tracing/immunohistochemical study. | the aim of the present study was to determine whether a dopaminergic mesolimbic pathway, as found in the brain of amniotes, also exists in anuran amphibians. for that purpose, application of retrograde tracers in the nucleus accumbens of rana perezi was combined with tyrosine hydroxylase immunohistochemistry. double labeled cells were found in the dorsomedial part of the posterior tubercle and, more frequently, in the midbrain tegmentum. it may be concluded, therefore, that a dopaminergic mesoli ... | 1995 | 7637889 |
| 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 |
| skeletal malformations induced by the insecticides zz-aphox and folidol during larval development of rana perezi. | tadpoles of rana perezi were kept for 14 weeks in water containing two sublethal levels of the carbamate insecticide zz-aphox or the organophosphate folidol. approximate concentrations of their active ingredients were 0.25 and 1 mg/l. resulting malformations were studied by skeletal analysis and histological and histochemical investigation of te rear limbs of the tadpoles. the pesticides caused the animals to have malformations of the spinal column (scoliosis) and/or limbs (short and thick long ... | 1995 | 7726646 |
| differential characteristics and regulation of arylamine and arylalkylamine n-acetyltransferases in the frog retina (rana perezi). | arylamine n-acetyltransferase activity (a-nat: e.c.2.3.1.5) from rana perezi retina was studied using p-phenetidine as specific substrate. enzyme characteristics and regulation were compared with respect to the arylalkylamine n-acetyltransferase (aa-nat: e.c.2.3.1.87) from the same tissue. a-nat activity is distributed in both neural retina and choroid-pigmented epithelium complex, showing a 10-fold higher specific activity in neural retina. in contrast, aa-nat activity is restricted to neural r ... | 1995 | 7787769 |
| 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 |
| serotonin n-acetyltransferase (nat) activity and melatonin levels in the frog retina are not correlated during the seasonal cycle. | the seasonal pattern of daily serotonin n-acetyltransferase (nat) and melatonin rhythms in the lateral eye of rana perezi has been characterized to assess any seasonal relationship between enzymatic activity and melatonin production and to evaluate the photothermal responses of such rhythms. in winter there was no daily rhythm either in nat activity or in melatonin production, although the highest values of nat activity and lowest melatonin concentrations were measured at this time. ocular melat ... | 1993 | 8282167 |
| the inhibition by indoleamines (tryptamine and serotonin) of ocular serotonin-n-acetyltransferase from rana perezi is temperature-dependent. | temperature effects on ocular serotonin n-acetyltransferase (nat) kinetics characteristics from rana perezi have been studied with respect to tryptamine and serotonin as substrates. monoamine oxidase (mao) activity does not interfere in nat assay at acceptoramine concentrations used in nat kinetics characterization from r. perezi retina. nat shows an inhibition by high substrate (serotonin) concentration, which is temperature-dependent. nat follows the michaelis-menten equation at low temperatur ... | 1993 | 8361660 |
| the carbamate insecticide zz-aphox induced structural changes of gills, liver, gall-bladder, heart, and notochord of rana perezi tadpoles. | embryos of rana perezi were kept under laboratory conditions and treated with carbamate zz-aphox at chronic doses of 0.02% and 0.14% for 9 weeks. both the histological study and the analysis of mortality show a direct relationship between the dosage and the effects of the pesticide. the histological study of the survivors over 56 days show damages in gills, liver, gall-bladder, heart, and notochord. damages on the epithelial of gills (on their distal portion) and gall-bladder recover over a few ... | 1993 | 8368863 |
| 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 |
| a segmental map of architectonic subdivisions in the diencephalon of the frog rana perezi: acetylcholinesterase-histochemical observations. | the work examines frog diencephalic subdivisions from a segmental viewpoint and adds a number of details to the atlas of the bullfrog diencephalon reported by neary and northcutt [1983]. acetylcholinesterase histochemistry was performed on brains of rana perezi, sectioned either sagittally or in a plane roughly parallel to the optic tract to optimize detection of segmented landmarks. this material provided a very detailed picture of individual neurons, neuropils and some fiber tracts expressing ... | 1996 | 8796963 |
| nitric oxide synthase activity in the olfactory bulb of anuran and urodele amphibians. | nitric oxide synthase activity was studied by means of nadph-diaphorase activity and nitric oxide synthase immunoreactivity in the main and accessory olfactory bulbs of the frog rana perezi and the newt triturus marmoratus. in both species, nadph-diaphorase staining was observed in all olfactory fibers. vomeronasal fibers were nadph-diaphorase-positive in triturus but they were nadph-diaphorase-negative in rana. nitric oxide synthase immunoreactivity was not observed in the primary afferents in ... | 1996 | 8816257 |
| do amphibians have a true locus coeruleus? | much controversy surrounds the identity of a locus coeruleus in amphibians because although previous studies on the isthmic region of the brain of anurans and urodeles revealed the presence of noradrenergic cell bodies they failed to demonstrate their projection to the telencephalon or the spinal cord. in the present study applications of texas red-conjugated dextran amines to the basal telencephalon or to the spinal cord in combination with tyrosine hydroxylase immunohistochemistry revealed tha ... | 1996 | 8856695 |
| topographical distribution of nadph-diaphorase activity in the central nervous system of the frog, rana perezi. | the distribution of nadph-diaphorase (nd) activity was histochemically investigated in the brain of the frog rana perezi. this technique provides a highly selective labeling of neurons and tracts. in the telencephalon, labeled cells are present in the olfactory bulb, pallial regions, septal area, nucleus of the diagonal band, striatum, and amygdala. positive neurons surround the preoptic and infundibular recesses of the third ventricle. the magnocellular and suprachiasmatic hypothalamic nuclei c ... | 1996 | 8867283 |
| 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 |
| effect of constant and fluctuating temperature on daily melatonin production by eyecups from rana perezi. | we analysed the effect of daily temperature cycles in relation to constant temperature on day/night melatonin synthesis in frog eyecups in culture. eyecups were cultured for 24 h under 12l:12d photoperiod and two thermal regimes, constant temperature (25, 15 and 5 degrees c) and thermoperiod (wl/cd, thermophase coinciding with photophase and cryophase coinciding with scotophase; and cl/wd, cryophase coinciding with photophase and thermophase coinciding with scotophase). a negative correlation be ... | 1997 | 9151432 |
| 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 |
| anatomical substrate of amphibian basal ganglia involvement in visuomotor behaviour. | the optic tectum of amphibians is known to play a major role in the control of visually elicited orienting movements, such as prey-catching and avoidance behaviours. the recent finding of a direct striato-tectal connection in the frog rana perezi prompted us to study in detail the anatomical substrate by which the basal ganglia of amphibians may modulate visuomotor behaviour. injections of anterograde tracers into the striatum were combined with applications of retrograde tracers in the mid-brai ... | 1997 | 9421170 |
| basal ganglia organization in amphibians: chemoarchitecture. | recent studies dealing with the investigation of the afferent and efferent connections of the basal ganglia of amphibians have revealed many similarities with basal ganglia structures of amniotes. in a further step, the chemoarchitecture of basal ganglia of the frog rana perezi has been investigated. for use as main markers of amphibian basal ganglia structures, antibodies against tyrosine hydroxylase, substance p, and enkephalin were selected. moreover, the distributions of nitric oxide synthas ... | 1998 | 9511919 |
| localization of adrenomedullin-like immunoreactivity in the hypothalamo-hypophysial system of amphibians. | the presence of adrenomedullin-like immunoreactive (ami) cell bodies and fibers in the hypothalamus and hypophysis of the amphibians rana perezi (anuran) and pleurodeles waltl (urodele) was examined by immunohistochemistry. a large population of ami neurons was found in the suprachiasmatic nucleus of both species. differently, ami cells in the magnocellular nucleus of the preoptic area were only found in the urodele, whereas dispersed cells in the caudal infundibular region were exclusively pres ... | 1998 | 9580198 |
| 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 |
| amphibian alcohol dehydrogenase. purification and characterization of classes i and iii from rana perezi. | 1999 | 10352704 | |
| origin of tectal cholinergic projections in amphibians: a combined study of choline acetyltransferase immunohistochemistry and retrograde transport of dextran amines. | immunohistochemistry for choline acetyltransferase (chat) revealed an extensive network of cholinergic fibers in the tectum of amphibians. the distribution of chat immunoreactive fibers was not restricted to superficial retinocipient layers, but also included deep tectal layers. the aim of the present study was to investigate the origin of the cholinergic inputs to the tectum of amphibians. for that purpose, application of retrograde tracers in the tectum of the anuran rana perezi and the urodel ... | 2016 | 10367962 |
| 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 |
| melatonin synthesis in the greenfrog retina in culture: i. modulation by the light/dark cycle, forskolin and inhibitors of protein synthesis. | melatonin is synthesized in the pineal gland and the retina of vertebrates. retinal serotonin n-acetyltransferase (nat) activity and melatonin show a daily rhythm with high levels during the dark phase of the photocycle. in some vertebrates, these retinal nat and melatonin rhythms are maintained in vitro. the aim of present work is to develop an eyecup culture system for the greenfrog (rana perezi), suitable to analyze the mechanisms of regulation of melatonin synthesis by simultaneous determina ... | 2000 | 10680576 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |