Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| phloretin sensitive active urea absorption in frog skin. | this report presents evidence for urea active absorption by isolated skin of rana esculenta. one of the supporting factors of such evidence is that at a low concentration the urea influx is five times greater than the outflux, in the absence of a chemical gradient. the transport shows a saturation kinetics with an apparent km = 1.33 mm and is inhibited by un uncoupling agent (fccp). 5 x 10(-4) m phloretin, added to the external side, markedly inhibits inward urea transport, whereas it is ineffec ... | 1982 | 6983053 |
| sex differences in liver non-specific esterases of the green frog rana esculenta. | 1. liver esterases of the green frog rana esculenta have been fractionated on disc electrophoresis, thin-layer electrofocusing and column electrofocusing. 2. the enzyme resolves in several molecular forms some of which result sex dependent, since they disappear in castrated animals and can be induced by sex hormone administration. 3. the enzyme molecular forms which depend on female hormones might be involved in cellular modifications of hepatocytes related to yolk protein synthesis. induced by ... | 1982 | 6983416 |
| beta-n-acetyl-d-glucosaminidase activity levels in atrophic gastrocnemius muscle of rana esculenta. | 1. the atrophic status induced by long-term sciatectomy or tenotomy is different, since only in the first case have we found an irreversible muscular degeneration. 2. up to 20 days after denervation or tenotomy the beta-n-acetylglucosaminidase showed increased specific activity. 3. the time-course of the beta-nag increase is closely correlated with the loss of contractile capacity. 4. beta-nag increases to 170% and does not fall in 20 days after cutting the nerve; but increases to 150% on day 4 ... | 1982 | 6983418 |
| [effect of n-ethylmaleimide on the active transport of sodium and its permeability in the skin of rana esculenta]. | n-ethyl maleimide (10(-3)m in the external fluid) strongly increases the permeability of urea and phenylalanine. however, the ratio phi 0 urea / phi 0 phenylalanine (a measure of membrane integrity) is not reduced. nem 10(-4)m elicits a small increase of urea permeability. nem (10(-3)m or 10(-4)m in the external fluid) stimulates na active transport across the frog skin. most probably the activation of na pump is due to an increase of na cellular pool, caused by the permeability increase elicite ... | 1982 | 6984336 |
| quantitative evaluation of the number of fibers in the right and left fasciculus retroflexus using horseradish peroxidase. | a quantitative evaluation of the number of fibers in the right and left fasciculus retroflexus (fr) was conducted in the frog rana esculenta after injections of horseradish peroxidase (hrp) in the habenular nuclei of the two sides of the brain and in the interpeduncular area in separate animals. it seems that the known morphological asymmetry of the habenular nuclei is not accompanied by a corresponding asymmetry of the fr and that there is an equivalent number of fibers in the fr after hrp inje ... | 1982 | 6984806 |
| changes in nuclear volume of purkinje cells in the cerebellum of the water frog (rana esculenta l.) in the annual cycle. | in sexually mature female and male rana esculenta l. frogs directly from natural habitat, in six characteristic periods of their life cycle, nuclear volume in purkinje cells of the cerebellum was determined. nuclear volume in purkinje cells changed distinctly in the course of the year. nuclear volume was greatest in females in the breeding period (3rd decade of may), and in males in the middle of the period of active life (2nd decade of july). nuclear volume was the smallest at the beginning of ... | 1980 | 7004100 |
| rejection of skin allo- and xenografts in the grass frog, rana temporaria and the edible frog, rana esculenta. | the fate of orthotopic dorsal skin allo- and xenografts at 22 +!- 2 degrees c in the grass frog, rana tempororai (rt) and in the edible frog, r. esculenta (re) which is an interspecific hybrid of r. ridibunda and r. lessonae. median survival times (msts) in experimental groups rt in equilibrium rt, re in equilibrium re and rt comes from re were 28, 26 and 25 days, respectively. in r. tempororia hosts the significantly shorter viability of xenografts than allogeneic grafts may be caused by the br ... | 1980 | 7006565 |
| seasonal variation in insulin and glucagon concentrations of rana esculenta (l.). | 1981 | 7014358 | |
| amino-acid sequence of an alpha-parvalbumin, pi = 4.88, from frog skeletal muscle. | the primary structure of the most basic (pi = 4.88) of the two major parvalbumins from frog skeletal muscle (rana esculenta) has been determined by partial automatic sequencing of the protein which exhibits a free n terminus, and a study of overlapping peptides obtained by cyanogen bromide cleavage and digestion with trypsin, thermolysin and armillaria mellea protease. this protein shows the typical structure of an alpha-parvalbumin. comparison of the primary structure of ion-binding loops of al ... | 1982 | 7042341 |
| [the morphology of amphibian skins: comparison between some species in different natural habitats]. | a comparison in the morphology of the skin in different species of amphibians has been performed in this note. species examined had different natural habitat: some of them were closely dependent on a watery environment (proteus anguinus, triturus cristatus, rana esculenta and r. graeca), whereas others were more or less adapted to life on land (rana dalmatina, salamandra salamandra, bufo bufo, b. viridis and hyla arborea). structural patterns of both epidermis and derm varied from species to spe ... | 1982 | 7115576 |
| purification and physical properties of arginase from xenopus laevis. | arginase from the liver of xenopus laevis has been purified to homogeneity by heat treatment, acetone fractionation, and isoelectric focussing. the main component had an isoelectric point (i.e.p.) of 7.3; there is a minor component of i.e.p. 7.8. the molecular weight of the enzyme, as determined by gel filtration on sephadex g200, is 76,000 daltons, substantially less than that of rat liver arginase studied concurrently. the molecular weight of the subunits, as determined by electrophoresis in s ... | 1982 | 7130924 |
| comparison of the pineal complex, retina and cerebrospinal fluid contacting neurons by immunocytochemical antirhodopsin reaction. | the presence of rhodopsin was investigated by an indirect immunocytochemical method in the pineal complex of various vertebrates (carassius auratus, cyprinus carpio, hypophthalamichthys molitrix, lucioperca lucioperca, triturus vulgaris, bombina bombina, rana esculenta, pseudemys scripta elegans, lacerta agilis et viridis, white leghorn chickens, rat), in the retina of lebistes reticulatus, lucioperca lucioperca, rana esculenta, lacerta agilis, pseudemys scripta elegans, the chicken and the rat, ... | 1980 | 7456628 |
| sequence and functional expression of an amphibian water channel, fa-chip: a new member of the mip family. | a new member of the family of water channel proteins (aquaporin-chip) related to the major intrinsic protein (mip) family is described. the cdna coding for this amphibian chip was cloned from frog (rana esculenta) urinary bladder, a model for the kidney collecting duct, using a rt-pcr cloning strategy. the encoded protein, designated fa-chip (frog aquaporin-chip), shows 77.4%, 42.4% and 35.6% identity with the three proteins now referred to as the aquaporins of the mip family, i.e., human chip28 ... | 1994 | 7515688 |
| action of capsaicin and related peptides on the ionic transport across the skin of rana esculenta. | capsaicin at low concentrations increases the short circuit current (scc) across frog skin. simultaneous measurements of both transepithelial fluxes of 22na or 36cl demonstrate that the scc increase is due to stimulation of sodium active absorption. capsaicin acts through the liberation of several peptides; thus these peptides were tested on the scc across frog skin. those more active are, in order of potency: cyclic calcitonin gene related peptide (cgrp), kassinin and eledoisin, substance p (sp ... | 2013 | 7516733 |
| phylogenetic aspects of the occurrence and distribution of secretogranin ii immunoreactivity in lower vertebrate gut. | a novel monoclonal antibody raised against bovine secretogranin ii (sg ii) was used in immunohistochemical studies on amphibian (rana esculenta), reptilian (podarcis sicula) and avian (gallus gallus) gut. sg ii immunoreactivity was detected in epithelial and nervous elements. cells immunoreactive for sg ii were examined by double immunostainings to determine whether they might also co-store certain previously known bioactive amine/peptide substances. almost all the endocrine cells immunoreactive ... | 1994 | 7529518 |
| regional and seasonal variations of rna synthesis in the brain of the green frog, rana esculenta. | changes of rna synthesis were demonstrated in neurons and ependymal cells of the green frog rana esculenta during the annual cycle using the mallory's trichrome stain as histochemical marker and autoradiography. since the higher affinity of the nuclei for aniline blue is consistent with the increase of rna content, the increase of rna synthesis was expressed as percentage of the blue stained nuclei (% bsn). neuronal transcription starts slowly in march or april, reaches a maximum in july and dec ... | 1994 | 7530512 |
| action of dopamine on the ionic transport across the isolated skin of rana esculenta. | dopamine addition to the internal fluid bathing the isolated frog skin results in a strong increase of short circuit current (scc) across this tissue. the effect is dose-dependent, 10(-4) m being the dose resulting in maximal effect. the measure of transepithelial fluxes of both 22na+ and 36cl- across symmetrical parts of skin short-circuited in permanence demonstrates that this effect is due to stimulation of na+ adsorption and cl- secretion. the former effect, but not the latter one, is mimick ... | 2013 | 7534500 |
| distribution of mrna encoding the fa-chip water channel in amphibian tissues: effects of salt adaptation. | a water channel, the frog aquaporin-chip (fa-chip) was recently cloned from rana esculenta urinary bladder. the 28.9 kda encoded protein shows 78.8%, 77.4%, 42.4% and 35.6% identity with rat chip28, human chip28, rat wch-cd and gamma-tip, other members of the new transmembrane water channel family (aquaporin-chip). we have now studied membranes from different frog (r. esculenta) organs employing semiquantitative pcr using fa-chip specific primers and an internal standard to quantify the pcr prod ... | 1995 | 7539499 |
| a new cutaneous nerve fiber connection with the frontal nerve in the frog rana esculenta: a morphological study. | the frontal nerve arises from the frontal organ, which represents the extracranial component of the pineal complex in some lower vertebrates, and interconnects the frontal organ with the epiphysis and the brain. the existence of a previously unreported nerve branch of the frontal nerve is described here in the frog rana esculenta and called the lateral nerve. the course of the lateral nerve and its junction with the frontal nerve have been consistently detected by means of different techniques: ... | 1995 | 7542543 |
| a novel neuropeptide cellular mechanism in amphibian interrenal steroidogenesis. | interrenals of female rana esculenta were incubated with gonadotropin-releasing hormone (gnrh), 9-ketoreductase inhibitor (palmitic acid), acetyl salicyclic acid, prostaglandin f2 alpha (pgf2 alpha), forskolin, isobutylmethyl xanthine (ibmx), dibutyril cyclic adenosine monophosphate (dbcamp). prostaglandin e2 (pge2), pgf2 alpha, testosterone and 17 beta-estradiol were assessed on the incubation media. in addition, in the same interrenals, 9-ketoreductase and aromatase activities were evaluated. ... | 1995 | 7544992 |
| biogenic amines in the taste organ. | the presence and content of biogenic amines in taste disk-bearing fungiform papillae of the frog, rana esculenta, the only available model of an isolated taste organ, were verified by means of hplc. fungiform papillae were found to contain measurable amounts of serotonin, epinephrine and norepinephrine. the amounts of serotonin and epinephrine were significantly higher in fungiform papillae than in the general mucosa of the tongue. moreover, the epinephrine content of fungiform papillae was foun ... | 1995 | 7552042 |
| effect of cholinergic secretagogue substances on the morphology of the harderian gland in the frog, rana esculenta. | the present study using secretagogue substances was undertaken to investigate harderian gland secretion in the frog, rana esculenta. carbamylcholine chloride and bethanechol injections caused enhancement of the secretory activity and hyperemia, while nicotine did not. morphological examinations showed reduced cellular height and dilated alveolar lumina, containing secretory granule discharge, nuclei and cytoplasmic fragments, indicating an apocrine and holocrine secretion type. the administratio ... | 1995 | 7553334 |
| expression of alpha sm actin in terrestrial ectothermic vertebrates. | alpha-smooth muscle (alpha sm) actin of endothermic vertebrates is selectively recognized by the monoclonal antibody anti-alpha sm-1. immunoreactivity to this antibody has been shown to be localized in the nh2-terminal sequence ac-eeed (chaponnier et al. 1994). among terrestrial ectothermic vertebrates, two amphibian (triturus vulgaris, rana esculenta) and three reptilian species (pseudemys scripta elegans, natrix natrix, podarcis sicula) were screened to investigate if their vascular and viscer ... | 1995 | 7553770 |
| fluctuations in levels of various gangliosides in the different tracts of the oviduct of the frog (rana esculenta) during the reproductive cycle. | the ganglioside content and pattern have been followed in the different tracts (rectus, convoluted and uterine) of the frog oviduct during the reproductive cycle. the main variations we observed are: a) average higher levels of ganglioside sialic acid in the preovulatory phase, with two peaks in march and april for the convoluted and rectus tract, respectively, and a more homogenous behaviour for the uterine tract; in all three tracts of the oviduct a minimum coincident with the ovulation has be ... | 2003 | 7558766 |
| distribution and ultrastructure of somatostatin-immunoreactive cells in the pancreas of rana esculenta. | apart from a description of the general organization of the endocrine pancreas, the present study is focussed on the distribution and ultrastructural morphology of somatostatin-immunoreactive cells in the pancreas of the frog rana esculenta. for light-microscopic histochemistry, the peroxidase-antiperoxidase technique was used. for the ultrastructural investigation, we employed the immunogold method. the endocrine pancreas of r. esculenta is composed of numerous islet-like structures, which cont ... | 1995 | 7598218 |
| morphological features of different regions in frog crista ampullaris (rana esculenta). | the cellular organization of different regions of the crista epithelium from the frog posterior semicircular canal was studied by light, transmission and scanning microscopy. the sensory epithelium consists of hair cells surrounded by supporting cells and basal cells located close to the basement membrane. three types of hair cells, namely club-like, cylindrical and pear-like cells differentially distributed along the crista could be recognized on the basis of their shape. club-like cells are lo ... | 1995 | 7612357 |
| similar fine structural localization of immunoreactive glutamate in the frog pineal complex and retina. | the distribution of immunoreactive glutamate was compared in the pineal complex (pineal and frontal organs) and retina of frogs (rana esculenta, r. arvalis, r. ridibunda, r. catesbeiana, bufo viridis, bombinator igneus) by postembedding immuno-electron microscopy. similar to retinal photoreceptors (rods and cones), bipolars and ganglion cells, the rod- and cone-like photoreceptors and the neurons of the pineal and frontal organs exhibited glutamate immunoreactivity. synaptic terminals of photore ... | 1995 | 7612360 |
| thermodynamic parameters of frog brain kappa-opioid receptors. | the thermodynamic parameters for [3h]-ethylketocyclazocine binding in frog (rana esculenta) brain membranes have been examined. computer-based nonlinear regression analysis of the untransformed equilibrium displacement data showed that this ligand bound to two sites with different affinities and capacities in this tissue. ka values derived from equilibrium displacement curves have been used for calculating the changes in the standard gibbs energy, enthalpy, and entropy during the binding process ... | 1995 | 7616237 |
| invertebrate and vertebrate immune cells express pro-opiomelanocortin (pomc) mrna. | we show here that hemocytes and leukocytes with phagocytic activity from both invertebrates (planorbarius corneus, viviparus ater) and vertebrates (carassius auratus, rana esculenta) express pro-opiomelanocortin (pomc) mrna, as assessed by in situ hybridization with a digoxigenin-labeled human dna probe. these data are in accord with previous observations from our laboratories on the presence in these cells of pomc-derived peptides and strongly suggest that these molecules--highly conserved thro ... | 1995 | 7620207 |
| vestibular compensation in the european green frog (rana esculenta l.) and effect of training on compensation. | compensation of the vestibular deficits following section of the ampullary nerve of a horizontal semicircular canal was studied from a behavioral point of view in the european green frog. post-rotation reactions, which are highly asymmetrical the day after the lesion, become symmetrical, as they are in intact animals, 45-60 days later. it was shown that vestibular and motor training given postoperatively did not enhance the rate at which compensation was achieved. | 1995 | 7620875 |
| [an analysis of the genetic structure of a hybrid population of green frogs, rana esculenta complex, from the flats of the danube]. | analysis of genetic structure of geographically isolated population of hybrid complex rana esculenta l. from danube delta according to a complex of biochemical gene markers was conducted. a parental species of rana ridibunda and hybrids ridibunda-lessonae of the first generation only were found in the population. the complete absence of genetic recombination and introgression of genes from the locus ldh-b, which was found in dnieper populations, is characteristic of the population. the differenc ... | 1995 | 7631428 |
| presence of immunoreactive pro-opiomelanocortin-derived peptides and cytokines in the thymus of an anuran amphibian (rana esculenta). | pro-opiomelanocortin (pomc)-derived peptide [adrenocorticotropic hormone (acth), beta-endorphin, alpha-melanocyte-stimulating hormone (msh)]- and cytokine (il-1 alpha, il-1 beta, il-2, il-6, tnf-alpha)-like molecules were demonstrated in pas positive epithelial cells of the thymus of the anuran amphibian rana esculenta by an immunocytochemical procedure. three groups of pas positive epithelial cells were identified in subcapsular cortex, inner cortex and medulla, respectively. the cells containi ... | 1995 | 7645006 |
| responses of ipsilateral retino-tectal (type i1) units of the frog (rana esculenta) to moving configurational bars. | in frogs, retinal information projecting to the ipsilateral optic tectum uses a complex, at least bi-synaptic, route. ipsilateral visual units recorded at the tectal level correspond to isthmic axon terminals. for a better approach of their visual function, these units have been stimulated with moving (v = 7.6 degrees/sec) configurational stimuli proved earlier to be able to elicit classical behavioural sequences in amphibians. in the presence of w("worm-like")-stimuli of increasing length (2 de ... | 1995 | 7671150 |
| reinnervation of frog sympathetic ganglia with somatic nerve fibres. | the formation of synapses in the last two ganglia of the sympathetic chain of the frog rana esculenta was investigated after anastomosing the 6th spinal nerve to the denervated ganglia in order to evaluate the reinnervation of deafferented sympathetic neurons with somatic cholinergic axons. the same ganglia were examined both electrophysiologically and morphologically from 25 to 280 days after the operation. in response to electrical stimulations of the anastomosed spinal nerve, synaptic transmi ... | 1995 | 7673599 |
| co-occurrence of substance p and enkephalin-like immunoreactivities in the prosencephalon of two amphibians. | we studied the co-occurrence of substance p-(sp) and leucine (or methionine) enkephalin (enk)-like immunoreactivities in the prosencephalon of two amphibians: rana esculenta l. (anura) and triturus carnifex laur. (urodela) using single and double immunohistochemical methods. the two peptides (sp-enk) were sometimes found colocalized in neuronal cell bodies and processes. double-labelled neurons were seen in the nucleus accumbens, lateral septal nucleus, preoptic area, dorsal and ventral hypothal ... | 1993 | 7682865 |
| effects of cytochalasin b on the morphology of secretory cells of rana esculenta fungiform papilla. | the effects of cytochalasin b on the three types of secreting cells (apical, paracoronal and parietal cells) present in the fungiform papilla of the frog's tongue were studied. cytochalasin b induced morphological modifications only in the apical secreting cells, localized in the sensorial area, without affecting the paracoronal cells or the parietal cells. the morphological features of treated apical cells showed that the drug induces two different effects: a disappearance of microfilaments and ... | 1993 | 7693063 |
| mesencephalic projections of the cochlear nucleus in the frog, rana esculenta. | the lectin phaseolus vulgaris leucoagglutinin was injected into chochlear nucleus in order to study the trajectory and projections of the auditory pathway in the frog. a strong contralateral and a weak ipsilateral fiber bundle representing the lemniscus lateralis could be followed to the torus semicircularis. the following areas of termination could be discerned in the mesencephalon: (1) each of the five subnuclei of the torus semicircularis received fibers from the cochlear nucleus, the largest ... | 1994 | 7725825 |
| the gonadotropin-releasing hormone (gnrh) neuron system of the clawed toad xenopus laevis. | the gnrh immunoreactive (gnrh-ir) neuronal system of the clawed toad xenopus laevis was studied and compared with the gnrh-ir system of the frog rana esculenta. polyclonal antibodies against mammalian (mgnrh) and chicken type-ii gnrh (cgnrh-ii), and monoclonal antibodies against mgnrh were used in the study. in the xenopus laevis, most of the immunopositive neuronal cell bodies were located in telencephalic (35-50 per cent) and diencephalic areas (50-65 per cent). about 15-20 per cent of the gnr ... | 1994 | 7725831 |
| comparison of melatonin-binding sites in the brain of two amphibians: an autoradiographic study. | neuroanatomic comparison of the binding capability of 2-[125i] iodomelatonin in the crested newt triturus carnifex laur. and the green frog rana esculenta, using quantitative autoradiographic techniques, revealed a heterogeneous distribution pattern. the highest and relatively high binding activities were shown to occur in the optic tracts and in the suprachiasmatic area of the hypothalamus and the optic tectum, respectively, of both species. low or no 2-[125i] iodomelatonin binding values were ... | 1995 | 7736557 |
| antimicrobial peptides from amphibian skin: an overview. | over the past three decades, numerous peptides have been isolated from amphibian skin secretions. many of these peptides were shown to be homologous to hormones and neurotransmitters of mammals. in recent years it has been shown that these secretions also contain a multitude of antimicrobial peptides. most of these peptides are positively charged and have a propensity for forming an amphipathic helix. other types of peptides have been detected as well, including one group which contain d-allo-is ... | 1994 | 7768159 |
| response of guanylate cyclase to atrial natriuretic factor in epithelial cells of the frog choroid plexus. | this study shows that the choroid plexus of rana esculenta contains a guanylate cyclase particulate (gcp), similar to that identified in mammalia, that is quite sensitive to the atrial natriuretic factor (anf). the cytochemical tests for gcp show that anf increases the enzymatic reaction products. deposits are observed on the apical portion, at the basal level and along the lateral edges of the epithelial cells, with the exclusion of some intercalary epithelial cells with reaction-lacking microv ... | 1995 | 7778097 |
| ethane 1,2-dimethane sulfonate effects on the testis of the lizard, podarcis s. sicula raf: morphological and hormonal changes. | ethane 1,2-dimethane sulfonate (eds) destroys leydig cells in the testis of some rodents (mice excluded), disrupts interstitial and germinal compartments in the frog, rana esculenta, while it stimulates testicular activity in the teleost, gobius paganellus. in the japanese quail the toxin removes mature spermatozoa. there is no information on eds effects in reptiles. the present study examines the effect of eds treatment in the lizard podarcis s. sicula raf during two different periods of the te ... | 1995 | 7789742 |
| synaptic relations of the trigeminal motoneurons in a frog (rana esculenta). | the cobalt tracing technique was used to study synaptic relations of trigeminal motoneurons and the axon terminals of the mesencephalic trigeminal nucleus (vmes) in a frog (rana esculenta). most of the small calibre vmes terminals containing spherical synaptic vesicles occupied presynaptic position in axodendritic contacts. axoaxonic contacts of vmes boutons were exclusively found at the postsynaptic site. the synaptic coverage of the trigeminal motoneuron dendritic tree increased somatofugally ... | 1994 | 7803156 |
| [genetic defects in inheritance and the variability of locus ldh-b in hybrid populations of rana esculenta complex (amphibia, ranidae)]. | the directed ingression of lhd-b gene from r. lessonae to r. ridibunda observed during hybridization between these species was confirmed in the present study. the ingression was accompanied by decreased of the initial allele activity, segregative disturbances in heterozygotes and changes in electrophoretic mobility. the population genetic analysis has shown stable preservation of abnormal alleles in hybrid populations. the results are discussed with reference to the concept of genetic instabilit ... | 2016 | 7804099 |
| influence of gonadectomy and steroid hormone replacement therapy on the gonadotropin-releasing hormone neuronal system in the anterior preoptic area of the frog (rana esculenta) brain. | effects of gonadectomy and sex steroid replacement therapy were studied on the anterior preoptic area-located gnrh-immunoreactive neurons in males and females of the frog, rana esculenta. removal of gonads caused a drastic reduction in the immunostaining as well as in the number of gnrh neurons in the anterior preoptic area of the brain in both sexes. replacement therapy with estradiol-17 beta, testosterone, and 5 alpha-dihydrotestosterone, given alone or in combination, enhanced the somal accum ... | 1994 | 7821779 |
| the androgen receptor mrna is up-regulated by testosterone in both the harderian gland and thumb pad of the frog, rana esculenta. | alpha 32p-labelled cdna probe from plasmid containing rat androgen receptor (rar) has been tested in hybridization experiments using rnas from the harderian gland and thumb pad of the edible frog, rana esculenta. northern blot analysis has shown a high degree of homology between the rar cdna and the frog androgen receptor mrna (far mrna); this has been supported by both the hybridization conditions (high stringency) and the molecular size of far mrna which is quite similar to those described in ... | 1994 | 7826887 |
| detection and localization of gonadotrophin-releasing hormone (gnrh)-like material in the frog, rana esculenta, ovary. | gnrh-like material has been identified using hplc followed by ria in the ovary of rana esculenta. during the reproductive cycle three immunoreactive gnrh peaks were eluted. one of them coeluted with s-gnrh, the other two forms between gnrh and cii-gnrh. during the recovery phase s-gnrh immunoreactivity disappears. by immunocytochemistry, cii-gnrh immunostaining was localized to granulosa cells while s-gnrh was present in the perinuclear zone of the oocytes. | 1994 | 7828025 |
| model of bicarbonate secretion by resting frog stomach fundus mucosa. i. transepithelial measurements. | in the present in vitro experiments on gastric fundus mucosa of rana esculenta we try to define the mechanism of alkaline secretion that is observed in summer frogs in the resting stomach (blockage of hcl secretion by ranitidine, 10(-5) mol/l). the transepithelial voltage and the rate of alkalinization (asr) of an unbuffered gastric lumen perfusate was measured as a function of serosal (and mucosal) fluid composition. asr was high (0.88 +/- s.e. 0.09 microeq.cm-2.h-1, n = 11) during serosal bath ... | 1994 | 7838688 |
| model of bicarbonate secretion by resting frog stomach fundus mucosa. ii. role of the oxyntopeptic cells. | in the present publication we report mainly electrophysiological studies on oxyntopeptic cells of frog gastric mucosa which aim at clarifying a possible involvement of these cells in the process of resting gastric alkali (hco3-) secretion, described in the preceding publication. the experiments were performed on intact gastric fundus mucosa of rana esculenta mounted in ussing chambers. after removal of the muscle and connective tissue layer oxyntopeptic cells were punctured from the serosal surf ... | 1994 | 7838689 |
| seasonal variations in the daily rhythm of melatonin and nat activity in the harderian gland, retina, pineal gland, and serum of the green frog, rana esculenta. | day-night variations of melatonin content and n-acetyltransferase (nat) activity were studied in the harderian gland (hg), retina, pineal gland, and serum of the green frog rana esculenta. throughout the year the retinal melatonin content was correlated with retinal nat activity and was always higher than those in the pineal gland and hg. on the other hand, in these structures diurnal fluctuations in nat activity were observed. there were clear seasonal differences in the magnitude of the noctur ... | 1994 | 7843568 |
| immunocytochemical localization of pomc-derived peptides (adrenocorticotropic hormone, alpha-melanocyte-stimulating hormone and beta-endorphin) in the pituitary, brain and olfactory epithelium of the frog, rana esculenta, during development. | developmental stages of rana esculenta, starting with the posterior limb-bud stage (stage 26) up to a few days after metamorphosis, were examined immunohistochemically to localize cells and fibers producing some pomc-derived peptides, namely, alpha-msh, acth and beta-end. anti acth and anti alpha-msh revealed a positive reaction in the pars intermedia during all stages of development included in this study, whereas no immunoreactivity in this pituitary zone was ever evidenced with anti beta-end. ... | 1994 | 7850861 |
| [genetic instability in inheritance of electrophoretic variants, coded by the ldh-b locus, in hybrid crosses of representatives of rana esculenta l. complex (amphibia, ranidae)]. | 1994 | 7858513 | |
| effects of gonadectomy and temperature on the n-acetyltransferase activity in the harderian gland of the green frog rana esculenta. | since, in the harderian gland (hg) of the hamster, the n-acetyltransferase (nat), the specific enzyme involved in the biosynthesis of melatonin, exhibits a sexual dimorphism, in the present study, we investigated whether such a dimorphism is present also in the hg of the green frog rana esculenta. in intact frogs, no significant differences emerged between males and females in the hg nat activity under both cold (10 degrees c) and warm (22 degrees c) temperature conditions. in female frogs, the ... | 1995 | 7858948 |
| sex steroid binding proteins in the plasma of the green frog, rana esculenta: changes during the reproductive cycle and dependence on pituitary gland and gonads. | sex steroid binding proteins (ssbp) have been reported in the plasma of female and male rana esculenta. in both sexes ssbp bind [3h]estradiol and [3h]testosterone with medium-high affinity and high specificity. using ion-exchange chromatography ssbp resolve into two peaks eluting at 0.27 m (peak i) and 0.36 m (peak ii) nacl. both peaks bind [3h]estradiol and [3h]testosterone equally well. isoelectrofocusing showed that peak i focused at ph 6.0 and 7.5, whereas peak ii focused at ph 6.0. ssbp cap ... | 1994 | 7883147 |
| somatostatin-immunoreactive cell in the gastrointestinal tract of the frog rana esculenta. | the morphology and topographic distribution of somatostatin-immunoreactive cells in the stomach and small intestine of the frog rana esculenta were studied at the light-microscopic level by the use of the peroxidase-antiperoxidase method. scattered immunostained cells occurred in all regions of the gastrointestinal tract investigated. in the small intestine, the number of these cells decreased gradually in the oral to anal direction, i.e. from the pyloric (antral) stomach to the entrance into th ... | 1995 | 7895281 |
| interstitial buffer capacity influences na+/h+ exchange kinetics and oxyntic cell phi in intact frog gastric mucosa. | we studied the influence of interstitial buffer capacity and co2-hco3- on oxyntic cell intracellular ph (phi) in intact frog gastric mucosa. oxyntic cells in stripped gastric mucosa of rana esculenta were loaded with the ph-sensitive dye 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein, and phi was assessed fluorometrically. in the presence of a constant serosal and luminal ph, oxyntic cell phi was dependent on the serosal but not the luminal concentration of cell-impermeable buffer ions such a ... | 1995 | 7900811 |
| a comparative study of melatonin production in the retina, pineal gland and harderian gland of bufo viridis and rana esculenta. | 1. the circadian patterns of melatonin and of its synthesizing enzyme n-acetyltransferase (nat) were investigated in the serum, retina, pineal gland and harderian gland (hg) of two amphibian species, bufo viridis and rana esculenta. 2. serum melatonin levels showed no diurnal fluctuations in bufo viridis, whereas, in rana esculenta, they exhibited a circadian rhythm, with the highest values occurring during the night. retina melatonin exhibited characteristic circadian patterns in both species, ... | 1993 | 7903612 |
| ionic selectivity of the mechano-electrical transduction channels in the hair cells of the frog sacculus. | in the isolated saccular macula of rana esculenta extracellular hair cell receptor currents evoked by mechanical stimulation of the otolithic membrane were recorded under transepithelial voltage clamp conditions. the ionic selectivity of the mechano-electrical transduction channels of the hair cells was determined by examining the effects of different concentrations of ca2+ and k+ in the apical solution on the transepithelial voltage at which the extracellular receptor current was zero (vrev). c ... | 1994 | 7914041 |
| presence of x-ag carrier in frog (rana esculenta) red blood cells. | evidence is presented that the high levels of internal l-glutamic and l-aspartic acid in frog (rana esculenta) red blood cells are due to the existence of a specific carrier for acidic amino acids of high affinity (km = 3 microm) and low capacity (vmax 0.4 mumol l-glu.kg-1 dry cell mass.10 min-1). it is na+ dependent and the incorporation of l-glutamic acid can be inhibited by l- and d-aspartate and l-cysteic acid, while d-glutamic does not inhibit. moreover, this glutamic uptake shows a bell-sh ... | 1994 | 7914933 |
| [3h]dynorphin1-8 binding sites in frog (rana esculenta) brain membranes. | opioid binding sites specific for [3h]dynorphin1-8 were characterized in the particulate membrane fraction of frog (rana esculenta) brain. the degradation of the radioligand during the assay was prevented by the use of a broad spectrum of peptidase inhibitors. the binding of [3h]dynorphin1-8 to frog brain membranes was stereoselective, reversible, saturable, and displaceable by a series of opioid ligands including dynorphin1-13, bremazocine, levorphanol and naloxone. the specific binding of [3h] ... | 1994 | 7915022 |
| the isolated and perfused working heart of the frog, rana esculenta: an improved preparation. | 1. an in vitro preparation of the intact heart of the frog rana esculenta was set up. 2. the isolated heart, perfused at constant pressure, was spontaneously beating and able to generate physiological values of output pressure, cardiac output, ventricle work and power. it showed the typical phenomenon of the "hypodynamic state" after a relatively constant time from the onset of the perfusion. 3. perfusion with air-saturated saline and 99.5% oxygen-saturated saline did not show significant differ ... | 1994 | 7926601 |
| the nature and distribution of gonadotropin-releasing hormones in brains and plasma of ranid frogs. | highly specific antisera and reversed-phase hplc were used to examine the nature and distribution of gonadotropin-releasing hormone (gnrh) in the brains and plasma of three species of rana frog previously reported to vary in the types and brain distributions of gnrh. the three species examined, rana pipiens, rana esculenta, and rana ridibunda, exhibit differences in total concentration and relative concentrations of gnrh in brain areas, but all three contain the mammalian and chicken-ii forms of ... | 1994 | 7926629 |
| regeneration of the testicular interstitial compartment after ethane dimethane sulfonate treatment in the hypophysectomized frog rana esculenta: independence of pituitary control. | the effects of ethane dimethane sulfonate (eds) on the testes of hypophysectomized frogs (rana esculenta) were investigated by light and electron microscopy. initial signs of interstitial cell damage were observed in eds- and eds plus pituitary homogenate (ph)-treated animals 5 days after a single injection of eds (100 mg/kg body weight). the germinal compartment in these two groups appeared disorganized adjacent to the damaged interstitial tissue only in the eds-treated animals, and by day 8, s ... | 1994 | 7926658 |
| opioid peptide modulation of stress-induced plasma steroid changes in the frog rana esculenta. | the present paper aims to evaluate whether a neuroendocrine system including opioids accounts for the effects of stress in the frog, rana esculenta. using an acute-stress paradigm, the involvement of hypothalamic opioid peptides was investigated biochemically as well as by in vivo studies. hplc and ria investigations confirm the presence of beta-endorphin-like peptides in the brain of this frog. several immunoreactive peaks are present, two of them coeluting with beta-endorphin and acetyl beta-e ... | 1994 | 7927279 |
| atpase activity of melanosomes in liver pigment cells of rana esculenta l. | luminometric methods show that melanosomes in liver pigment cells of rana esculenta l. have endogenous atp and atpase activity. the km value of atpase is 0.42 x 10(-8) mol/l at ph 7.0. inhibition of atpase by antimycin and by ouabain is not effective. in the presence of an excess of adp and pi, atp synthesis was observed. | 1994 | 7953071 |
| the contralaterally projecting neurons of the isthmic nucleus in five anuran species: a retrograde tracing study with hrp and cobalt. | the morphology of projection neurons of the isthmic nucleus was studied in rana esculenta, r. nigromaculata, bufo marinus, b. bufo gargarizans, and xenopus laevis from a comparative anatomical point of view. the main point of this work was to provide an anatomical basis for electrophysiological studies. neurons projecting to the ipsilateral optic tectum were labeled by retrograde transport of horseradish peroxidase and cobaltous lysine complex injected into the optic tectum. contralaterally proj ... | 1994 | 7962721 |
| the c-wave of the electroretinogram possesses a third component from the proximal retina. | erg and light-induced extracellular potassium ([k+]o) changes have been measured in isolated retinas of both rana esculenta and rana temporaria. the conditions of the preparations have been varied. isolated frog retinas kept receptor side-upward in a moist chamber without perfusion showed the well-known slow piii in the erg. retinas superfused from the receptor side, with o2 enrichment at their vitreal surface, however, exhibit a slow cornea-positive potential in the erg. the slow erg-potentials ... | 1994 | 7975304 |
| exocytosis in the lingual mucus cells of rana esculenta evoked by acetylcholine: observation of living cells by confocal laser scanning microscopy. | exocytosis of a secretory cell is believed to occur when a part of the limiting membrane of the secretory granules fuses with the luminal plasma membrane to release their contents. using a confocal laser scanning microscope, we have studied these events in living frog lingual gland cells. in a differential interference contrast (dic) mode, secretory granules were found to be stable in general, but after stimulation with acetylcholine chloride (ach) of more than 1 microm concentration, there were ... | 1993 | 8007450 |
| multiple sources of the pituitary pars intermedia innervation in amphibians: a dii retrograde tract-tracing study. | afferent projections to the pituitary pars intermedia were studied using the dii tract-tracing technique in two amphibian species, the urodelan triturus carnifex, and the anuran rana esculenta. after dii crystal application into the pituitary intermediate lobe, in both species cells were retrogradely labeled in the preoptic nucleus, in the supra- and retro-chiasmatic hypothalamus and in the brainstem (especially in the area indicated as locus coeruleus). the findings are discussed in relation to ... | 1994 | 8047275 |
| immunohistochemical localization of chromogranin a and b in the endocrine cells of the alimentary tract of the green frog, rana esculenta. | novel monoclonal antibodies to human chromogranin a (cga) and chromogranin b (cgb) were used to investigate the presence of immunoreactive (-ir) elements in the alimentary tract of the green frog rana esculenta. numerous cga-ir and a few cgb-ir endocrine cells were found within the gut mucosa, from the oesophagus to the cloaca, with some local differences in density. co-localization studies demonstrated that they were co-stored in almost all the serotonin-ir, the amylin-ir or islet amyloid polyp ... | 1994 | 8082125 |
| characterization of the type of carbohydrate chains of the higher molecular weight (140 kda) acid phosphatase of the frog liver. | 1. the higher molecular weight, (hmw, m(r) 140 kda) acid phosphatase (acpase) of the frog liver (rana esculenta) was separated into enzymatically active components by isoelectric focusing in an immobilized ph gradient and their carbohydrate chains were analyzed by specific lectin binding after native blotting. 2. the lectin-binding patterns obtained with cona, wga, lch and pna as well as with wga and pna after desialylation indicate that the frog liver hmw acpase contains predominantly n-linked ... | 1993 | 8138034 |
| a phorbol ester and calcium ionophore regulate sex steroid and prostaglandin release by follicles of the anuran rana esculenta and the urodele triturus carnifex. | the aim of this work was to study the relationships among protein kinase c (pkc), calcium, prostaglandins (pgs), and sex steroids in follicles of rana esculenta and triturus carnifex. follicles, oocytes, and wall cells of follicle (theca and granulosa cells) were incubated in vitro with an activator of pkc, phorbol-12-myristate-13-acetate (pma), a calcium ionophore (a23187), an antagonist of calcium channel, verapamil, pma + a23187, prostaglandin f2 alpha (pgf2 alpha), and prostaglandin e2 (pge2 ... | 1994 | 8138111 |
| antimicrobial peptides from skin secretions of rana esculenta. molecular cloning of cdnas encoding esculentin and brevinins and isolation of new active peptides. | three cytolytic peptides, termed brevinin-1e, brevinin-2e, and esculentin, were isolated from skin secretions of the european frog rana esculenta (simmaco, m., mignogna, g., barra, d., and bossa, f. (1993) febs lett. 324, 159-161). nucleotide sequence analysis of cdnas coding for the corresponding precursors revealed that in all of them a single copy of the sequence of the mature peptide is present preceded by a dibasic cleavage site and followed by a stop codon. the signal peptides of these pre ... | 1994 | 8163497 |
| ultrastructural and cytochemical analysis for adenyl cyclase in frog choroid plexus. | an ultrastructural and cytochemical analysis of the anterior choroid plexus in adult rana esculenta was undertaken. the epithelial cells are implicated in the production of cephalorachidian liquid by transporting metabolites from the blood and by synthesizing and secreting activity. the epithelial cells are also capable of re-absorbing catabolites from the cephalorachidian liquid. the presence of adenylate cyclase, along the basal and lateral membranes in some epithelial cells and along the apic ... | 1994 | 8171424 |
| characterization of tension decline in different types of fatigue-resistant skeletal muscle fibres of the frog. low extracellular calcium effects. | twitch and tetanic tension have been measured in single skeletal muscle fibres (m.ileofibularis, rana esculenta and rana temporaria). on the basis of resistance to fatigue produced by repetitive tetanic stable frequency stimulation with various numbers of stimulation trains, twitch fibers were subdivided in three groups (resembling those as described by westerblad and lännergren 1986 in xenopus), that is fatigue-resistant (fr), moderately fatigued (mf) and easily fatiguing (ef). it was found fur ... | 1993 | 8181694 |
| configuration of light responses in isolated retinal rods. a patch-clamp study. | the whole-cell patch-clamp technique was employed to investigate the light responses of single retinal rods of the frog (rana esculenta and r. temporaria). in the majority of experiments, completely isolated cells were studied. coupling with neighboring cells gave rise to a more complex response configuration. responses were recorded under voltage-clamp and under current-clamp conditions. stimulus response curves were measured in experiments with local stimuli illuminating only parts of the oute ... | 1994 | 8188065 |
| seasonal changes in plasma growth hormone and prolactin concentrations of the frog rana esculenta. | plasma growth hormone (gh), prolactin (prl), and vitellogenin (vtg) concentrations were determined during the annual reproductive cycle of the frog rana esculenta. plasma gh and prl were measured using a ria that employed purified bullfrog (rana catesbeiana) gh and prl as standards and radioligand, and their respective antibodies. using elisa, plasma vtg titers were related to ovarian weight. gh, prl, and vtg displayed different trends related to season and sex. in male frogs the gh and prl tren ... | 1994 | 8194739 |
| [a population genetics analysis of the structure of hybrid populations of rana esculenta l. complex (amphibia, ranidae)]. | population-genetic analysis conducted in hybrid populations of rana esculenta complex from neighbourhood of kiev has shown a high portion of recombinant frogs within rana esculenta specimens and limitation of gene flows from one species to the other. the mechanisms of limitations are connected with assortative crossings within r. ridibunda and r. lessonae and low viability of frogs with a recombined genotype. | 1993 | 8212328 |
| possible roles for prostaglandins e2 and f2 alpha in seasonal changes in ovarian steroidogenesis in the frog (rana esculenta). | concentrations of pge2, pgf2 alpha, androgens and oestradiol in plasma, and ovary weights were measured in the female frog, rana esculenta, during the annual breeding cycle. experiments were carried out in vivo to study the effects of pge2 and pgf2 alpha on plasma sex steroids during the following stages: pre-reproduction (april), reproduction (may), post-reproduction (june) and recovery (october). experiments were performed in vitro during these stages to evaluate the effects of these two prost ... | 1993 | 8345472 |
| two gnrhs fluctuate in correlation with androgen levels in the male frog rana esculenta. | chickenii-(cii-) and salmon (s-) gnrh levels have been measured in the male frog rana esculenta during the annual cycle. the presence of pituitary binding activity for both peptides and plasma androgen levels has been investigated in order to give insight into the significance of the dual control exerted by the gnrh forms present in the r. esculenta brain. chickenii- and s-gnrhs showed high values during the spring-summer period. conversely, while cii-gnrh peaked in february, s-gnrh declined slo ... | 1993 | 8354991 |
| glycogen phosphorylase activity in the liver of the frog rana esculenta. | 1. phosphorylase activity has been assayed in liver extracts of the frog, rana esculenta, during the winter period. in native conditions, most of the phosphorylase is present as amp-independent activity and shows properties similar to those of the a form of the liver enzyme from other vertebrates. 2. it is suggested that regulation of phosphorylase activity is through interconversion between a and b forms operated by endogenous phosphorylase kinase and phosphatase. 3. kinetic studies show hyperb ... | 1993 | 8359024 |
| the effects of gonadectomy and testosterone treatment on the harderian gland of the green frog, rana esculenta. | the effects of gonadectomy and testosterone treatment on the fine structure of the harderian gland in male and female green frogs were investigated in different periods of the year. gonadectomy, carried out when the glands are in the lowest secretory phase (september), causes degenerative changes consisting of a reduction of the rough endoplasmic reticulum, the appearance of autolysosomes, and an increase of nuclear heterochromatin. these effects can be prevented by testosterone treatment. no ca ... | 1993 | 8364965 |
| in-vitro effects of mammalian and amphibian prolactins on hepatic vitellogenin synthesis in rana esculenta. | male and female rana esculenta liver was induced in an in-vitro system by homologous and rana catesbeiana pituitary to synthesize and release vitellogenin, a lipoglycophosphoprotein precursor of yolk proteins, lipovitellins and phosvitins, in oviparous vertebrates. in the present experiments, the action of prolactin on hepatic vitellogenin synthesis and release was investigated, using ovine prolactin and rana catesbeiana prolactin. the effects of prolactin on hepatic vitellogenin synthesis displ ... | 1993 | 8371074 |
| 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase from frog skeletal muscle: purification, kinetics and immunological properties. | fructose 2,6-bisphosphate is the most potent activator of 6-phosphofructo-1-kinase, a key regulatory enzyme of glycolysis in animal tissues. this study was prompted by the finding that the content of fructose 2,6-bisphosphate in frog skeletal muscle was dramatically increased at the initiation of exercise and was closely correlated with the glycolytic flux during exercise. 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase, the enzyme system catalyzing the synthesis and degradation of fructose ... | 1993 | 8391552 |
| a quantitative autoradiographic study of gabaa and benzodiazepine receptors in the brain of the frog, rana esculenta. | specific binding sites for gabaa and benzodiazepines were detected in the brain of the frog rana esculenta after the in vitro incubation of tissue sections with their respective specific agonists [3h] muscimol and [3h] flunitrazepam. conditions for the binding assay were optimized and as a result binding was saturable and specific. quantitative autoradiographic receptor measurements in the different brain sections showed that elevated levels of [3h] muscimol binding sites were found in the two l ... | 1993 | 8395952 |
| prostaglandin e2 and prostaglandin f2 alpha involvement in the corticosterone and cortisol release by the female frog, rana esculenta, during ovulation. | interrenal and ovarian tissues of rana esculenta were incubated in vitro during the preovulatory, ovulatory and postovulatory phases to study the basal release of prostaglandin e2 (pge2), prostaglandin f2 alpha (pgf2 alpha), corticosterone, and cortisol. the effects of exogenous pge2 and pgf2 alpha on interrenal and ovarian corticosteroid release were also studied. in addition, the plasma values of these four hormones were assessed during the same phases. during in vitro interrenal incubations, ... | 1993 | 8409898 |
| dopamine regulation of testicular activity in intact and hypophysectomized frogs, rana esculenta. | in intact frogs, both gnrha and l-dopa were able to increase testicular and plasma androgen levels and to induce spermiation. the dopamine antagonist pimozide inhibited both the effects of l-dopa but not those of gnrha. hypophysectomy reduced androgen levels, but spermiation was still induced by both gnrha and l-dopa, suggesting that these agents can directly influence the testis through a route not involving the pars distalis. again, pimozide antagonised spermiation induced by l-dopa but not th ... | 1993 | 8428613 |
| distribution of proneuropeptide y-derived peptides in the brain of rana esculenta and xenopus laevis. | the distribution of proneuropeptide y-containing perikarya and nerve fibers in the brain of rana esculenta and xenopus laevis was determined with antisera directed toward neuropeptide y and the carboxyl terminal flanking peptide. the distribution of proneuropeptide y-like immunoreactivity was similar in both anurans. in the telencephalon, immunoreactive perikarya were found in the olfactory bulb, all subdivisions of the pallium, the septum, pars lateralis of the amygdala, the nucleus accumbens, ... | 1993 | 8440780 |
| freeze-fracture characterization of cell types at the surface of the taste organ of the frog, rana esculenta. | the ultrastructure and distribution of intramembrane particles in the chemoreceptor surface of the frog taste organ have been studied by means of freeze-fracture. sustentacular, wing, mucous cells and two different types of putative taste cells were found to reach the free surface of this chemoreceptor. each of these cell types was characterized by a different pattern and density of intramembrane particles in the free surface. wing cells displayed a relatively low number of large intramembrane p ... | 1993 | 8445408 |
| lipoprotein metabolism in the frog rana esculenta. | 1. the isoprenoid metabolism of the green frog has been studied, taking into consideration the transport and uptake mechanisms of plasma lipoproteins. 2. the lipoprotein complexes separated on kbr gradient showed six discrete peaks in both sexes. 3. the mechanisms of cellular uptake have been studied by immunological procedures. a molecule homologous to rat ldl receptor, and sharing its ability to bind only specific lipoproteins, has been shown. 4. homology at mrna level has also been demonstrat ... | 1993 | 8448988 |
| mammalian gonadotropin-releasing hormone increases pgf2 alpha production activating diacylglycerol lipase in rana esculenta interrenal. | the aim of the present paper was to clarify if the prostaglandin f2 alpha (pgf2 alpha) production stimulated by mammalian gonadotropin-releasing hormone (mgnrh) comes from arachidonic acid (aa) freed by diacylglycerol (dag) and/or membrane phospholipids in the interrenal of rana esculenta. interrenals of rana esculenta were incubated with inhibitors of phospholipase a1 (pla1), phospholipase a2 (pla2), phospholipase c (plc), protein kinase c (pkc) and diacylglycerol lipase (daglipase) in the pres ... | 1993 | 8452754 |
| localization of fibronectin in the frog skin. | in this review, we present structural and ultrastructural localizations of fibronectin (fn) in the larval and adult skin of the frog (rana esculenta) either in in vivo or in in vitro conditions. the ventral skin of the tadpole contains membrane-associated fn-plaques disposed around the epidermal and dermal cells during their climactic rearrangement. moreover, lines of fibrillar fn are detected inside the breaks opened in the derived collagen. the ventral skin of the adult frog reveals fn distrib ... | 1993 | 8470096 |
| opioids and testicular activity in the frog, rana esculenta. | the presence and activity of brain, pituitary and testicular beta-endorphin (beta-ep)-like material have been studied in the frog, rana esculenta, using reverse-phase high-pressure liquid chromatography, coupled with radioimmunoassay and immunocytochemistry. in-vivo and in-vitro treatments with naltrexone were carried out to assess the putative physiological activity of opioid peptides. beta-ep(1-31) and (1-27), together with their acetylated forms, have been identified in brain, pituitary and t ... | 1993 | 8492076 |
| novel antimicrobial peptides from skin secretion of the european frog rana esculenta. | three antimicrobial peptides were isolated from skin secretion of the european frog, rana esculenta. two of them show similarity to brevinin-1 and brevinin-2, respectively, two antimicrobial peptides recently isolated from a japanese frog [morikawa, n., hagiwara, k. and nakajima, t. (1992) biochem. biophys. res. commun. 189, 184-190]. the third one, named esculentin, is 46 residues long and represents a different type of peptide. all these peptides have as a common motif an intramolecular disulf ... | 1993 | 8508915 |
| the effects of testosterone and estradiol on mast cell number in the harderian gland of the frog, rana esculenta. | the harderian gland (hg) of the frog rana esculenta contains mast cells in the interstitial tissue. the mast cell number (mcn) is influenced by sex hormones. gonadectomy in both sexes provoked a decrease in mcn in january, while no effect was observed in september. sex hormone-replacement therapy gave different results; estradiol treatment in castrated males and females always increased mcn, while testosterone did not. acute estradiol treatment provoked an increase in mcn on days 2 and 4 of trea ... | 1995 | 8528017 |
| changes in proto-oncogene activity in the testis of the frog, rana esculenta, during the annual reproductive cycle. | proto-oncogenes are said to influence the regulation of cellular growth and differentiation. myc, fos, jun, and mos protein localization has been studied by immunocytochemistry in the testis of the frog, rana esculenta, during the annual reproductive cycle. oncoproteins have been localized in the primary and secondary (i and ii) spermatogonia (spg). myc and mos also appear in i and ii spermatocytes (spc) while jun appears in ii spc. myc, fos, and jun in spg translocate in the nucleus during the ... | 1995 | 8536921 |
| na+ and cl- net absorption by the isolated skin of rana esculenta. | in the last five years, several measurements of 22na+ influx (ji) and outflux (jo) across symmetrical parts of the isolated skin of rana esculenta, under permanent short circuitation, were performed in our institute. the mean value of the 22na+ net fluxes (ji-jo) exceeded the mean value of the short circuit current measurements (1.14 +/- 0.04 versus 0.98 +/- 0.02 microe.cm-2.h-1, 253 experiments). since this discrepancy could be due to a concomitant cl- net absorption, 36cl- unidirectional fluxe ... | 1995 | 8548488 |
| chicken gnrh-ii and salmon gnrh effects on plasma and testicular androgen concentrations in the male frog, rana esculenta, during the annual reproductive cycle. | in the frog, rana esculenta, two molecular forms of gnrh, coeluting with chicken (c) gnrh-ii and salmon (s) gnrh, have been detected using hplc and radioimmunoassay. mammalian (m) gnrh seems to be also present. in amphibians the role of cgnrh-ii seems to be primarily the involvement in the regulation of neuroendocrine processes and, while the mgnrh has been postulated to act as a neurotransmitter and/or neuromodulator, the activity of sgnrh-like material has not been investigated. therefore, we ... | 1995 | 8564791 |
| the paracoronal (marginal) cells of fungiform papilla of rana esculenta. | paracoronal secretory cells can be observed outside the sensorial area of the fungiform papilla of rana esculenta. the morphology of these cells, the type of secretion and their function have, to date, only been incidentally described. by scanning electron microscopy (sem), the paracoronal cells appear as swallow's-nest-shaped formations with openings 10-15 microns in diameter. the walls of paracoronal cells are characterized by laminar processes subdividing the interior hollow. the cavity of th ... | 1995 | 8568442 |
| a voltage-dependent and ph-sensitive proton current in rana esculenta oocytes. | voltage clamp technique was used to study macroscopic ionic currents in rana esculenta oocytes. depolarization steps led to the activation of a single type of outward current (iout) when contaminant potassium and calcium-dependent chloride currents were pharmacologically inhibited. the voltage threshold of iout activation was 10 mv and this current, which did not inactivate, presented a deactivation the time constant of 73 +/- 21 msec (n = 26) corresponding to a membrane voltage of -60 mv. its r ... | 1995 | 8568856 |