Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| cell adhesion to extracellular matrix in normal rana pipiens gastrulae and in arrested hybrid gastrulae rana pipiens female x rana esculenta male. | rana pipiens eggs fertilized by rana esculenta sperm (esc) hybrid embryos develop until gastrulation in control rana pipiens embryos (pip) and then show morphogenetic arrest. after arrest, esc do not gastrulate but live for 5 days as blastula-like embryos. we studied the distribution of fibronectin (fn)-containing fibrils and integrin (int) in pip and esc. there are many fn-fibrils in pip organized in anastomosing networks radiating away from the center of individual cells and across intercellul ... | 1990 | 2295369 |
| prostaglandin e2 enhances the sodium conductance of exocrine glands in isolated frog skin (rana esculenta). | prostaglandins are known to stimulate the active transepithelial na+ uptake and the active secretion of cl- from the glands of isolated frog skin. in the present work the effect of prostaglandin e2 (pge2) on the glandular na+ conductance was examined. in order to avoid interference from the na+ uptake and the glandular cl- secretion the experiments were carried out on skins where the cl- secretion was inhibited (the skins were bathed in cl- ringer's solution in the presence of furosemide, or in ... | 1990 | 2304070 |
| purification and characterization of bioactive peptides from skin extracts of rana esculenta. | the peptide fraction extracted by methanol from the skin of rana esculenta, a species widely distributed in western europe, was investigated. the pharmacological activity found in the extract is attributable to the presence of authentic bradykinin, together with a shorter, partially active version of this molecule, des-arg9-bradykinin. also the bradykinin fragment 1-7 has been isolated, but it was inactive in our bioassay system. moreover, a family of hydrophobic peptides has been purified and c ... | 1990 | 2317508 |
| [a study of the "outward potassium channel" (opc) in the frog oocyte. i. a study of the "cell-attached" configuration]. | a single channel current was studied in the membrane of the immature oocyte of the european frog (rana esculenta) by using the "patch clamp" technique in the "cell attached" configuration. single channel activity appeared as short outward currents when membrane potential was made positive inside; full activation required seconds to be complete, no inactivation being appreciable. deactivation (or current block) upon membrane repolarization was so fast that no inward current could be detected in a ... | 1990 | 2322442 |
| sialic acid and neuraminidase activity in the frog oviduct: comparative biochemical investigation in the different tracts during the reproductive cycle. | 1. a biochemical study was carried out on the protein-bound and lipid-bound sialic acid, and neuraminidase activity in the different tracts of the oviduct of the frog rana esculenta during the reproductive cycle. 2. plasma sexual steroids were also investigated by ria. 3. fluctuations in neuraminidase activity are related to that of glycoprotein sialic acid and plasma estradiol. glycolipid sialic acid does not have a close relationship either with neuraminidase or plasma estradiol. 4. very high ... | 1990 | 2331873 |
| effect of histamine on the basolateral k+ conductance of frog stomach oxyntic cells and surface epithelial cells. | the transepithelial potential difference (vt) and resistance (rt) and the basolateral cell membrane potential (vs) of oxyntic cells (oc) and surface epithelial cells (sec) were measured in isolated stomachs of rana esculenta. at rest, vs of oc and sec was virtually identical [-66.3 +/- 4.5 (sd) (n = 10) and -67.3 +/- 5.9 mv (n = 9)] and both cells responded to increasing serosal k+ concentration from 4 to 13 mmol/l with virtually the same depolarization (delta vs,k) of +16.2 +/- 2.0 and +16.0 +/ ... | 1990 | 2333976 |
| [the cellular mechanisms of the physiological action of iodobromide mineral waters]. | the experiments on edible frogs have revealed the relationship between the effect of sodium chloride, skin potential difference and micro-components iodide and bromide present in the solution. the results obtained furnish the additional information on the synergistic action of mineral water iodide and bromide on the body. iodide ions were found to act mainly through inhibition of sodium channels of cellular membranes, while bromide ions are likely to affect na, k-atpase. | 2015 | 2336825 |
| effect of mucosal h+ and chemical modification on transcellular k+ current in frog skin. | a transcellular k+ current (ik) was established across the skin of the frog rana temporaria, whose apical k+ permeability had been previously stimulated by exposure to k(+)-rich media. short-term (less than or equal to 15 s) mucosal ph-titration of ik indicated two titrated groups (a and b), with apparent pka of 6 and pkb of 3. the height of the titration steps, a and b, varied from skin to skin. intracellular (i) h(+)-sensitive microelectrode studies on rana esculenta skin (which lacks apical p ... | 1990 | 2337622 |
| nerve sprouting induced by a piece of peripheral nerve placed over a normally innervated frog muscle. | 1. the effects of a segment of peripheral nerve on the innervation of a skeletal muscle were investigated in the cutaneous pectoris muscle of the frog rana esculenta. an explant of the sciatic nerve was placed in an aneural region of the muscle at a distance of 1-3 mm from the zone of neuromuscular junctions. the muscles were examined morphologically and electrophysiologically at different post-operative times. 2. after the first month nerve sprouts were seen arising from both nerve terminals an ... | 1990 | 2348389 |
| nadph-diaphorase positive amacrine cells in the retinae of the frog (rana esculenta) and pigeon (columbia livia). | the distribution of nadph-diaphorase positive cells was examined histochemically in the retinae of the pigeon and frog. in the pigeon, three different types of amacrine cells were identified in the inner nuclear layer (inl) on the basis of cell body size and staining intensity. in the frog two types of nadph-diaphorase positive amacrine cells have been demonstrated in the inl. therefore, the nadph-diaphorase method selectively stains several subtypes of amacrine cells in the retina of lower vert ... | 1990 | 2364012 |
| histochemical demonstration of nadph-diaphorase activity in the pineal organ of the frog (rana esculenta), but not in the pineal organ of the rat. | using the histochemical method for the demonstration of nadph-diaphorase activity, the pineal organ of the frog and rat was investigated in serial sections. a positive nadph-diaphorase activity was demonstrated in pinealocytes and nerve cells in the pineal organ of the frog, but not in the rat. an intense activity existed in the apical portion of the photosensitive pinealocytes of the frog. large nadph-diaphorase positive nerve cells (15-20 microns in diameter) were located within the parenchyma ... | 1990 | 2372437 |
| localization of pigment cells in cultured frog skin. | the pigmentation pattern of ventral skin of the frog rana esculenta consists mainly of melanophores and iridophores, rather than the three pigment cells (xanthophores, iridophores, and melanophores) which form typical dermal chromatophore units in dorsal skin. the present study deals with the precise localization and identification of the types of pigment cells in relation to their position in the dermal tracts of uncultured or cultured frog skins. iridophores were observed by dark-field microsc ... | 1990 | 2375284 |
| isolated cells of the frog sinus venosus: properties of the inward current activated during hyperpolarization. | single sinus venosus cells from frog, rana esculenta, were isolated using an enzymic dispersion procedure, involving applications of collagenase and protease. about 40%-60% of the cells showed spontaneous contractions. isolated cells were studied in the whole-cell configuration. regenerative action potentials were tetrodotoxin-insensitive and similar to those recorded in multicellular preparations. hyperpolarizing pulses in the voltage range negative to -50 mv induced the activation of a time-de ... | 1990 | 2381767 |
| morpho-functional characterization of cultured pigment cells from rana esculenta l. liver. | a simple method to isolate and culture liver pigment cells from rana esculenta l. is described which utilizes a pronase digestion of perfused liver, followed by sedimentation on a ficoll gradient. a first characterization of isolated and cultured cells is also reported. they show both positivity for nonspecific esterases, and phagocytosis ability, like the cells of phagocytic lineage. furthermore, after stimulation with a phorbol ester, these cells generate superoxide anions. at phase contrast m ... | 1990 | 2384443 |
| circannual rhythm of the melanin content in frog liver (rana esculenta l.). | the melanin content of rana esculenta l. liver varies according to a circannual statistically significant rhythm, as shown by variance and single cosinor analysis. the maximum is found in autumn-winter, the minimum in spring-summer. the linear regression analysis shown a negative correlation between the amount of melanin and the environmental temperature. | 2016 | 2385566 |
| lampbrush and mitotic chromosomes of the hemiclonally reproducing hybrid rana esculenta and its parental species. | mitotic chromosomes of the european water frogs rana ridibunda and rana lessonae, the parental species of rana esculenta, differ significantly in their centromeric regions: when c-banded or when made fluorescent, the centromeres of r. ridibunda (and of ridibunda chromosomes in r. esculenta) are visible as a conspicuous dark granule or as a conspicuous fluorescent spot; the centromeres of r. lessonae (and of the lessonae chromosomes in r. esculenta) are inconspicuous or not fluorescent. lampbrush ... | 1990 | 2391468 |
| caffeine and the myoplasmic calcium removal mechanisms in cut frog skeletal muscle fibres. | antipyrylazo iii myoplasmic calcium transients were recorded in cut skeletal muscle fibres of the frog (rana esculenta), using the double vaseline-gap voltage-clamp system. intracellular calcium removal mechanisms were analysed, using a slightly modified model taken from the literature. parameter values reported here are generally consistent with those obtained by the original model. caffeine (0.5 mmol.l-1) moderately enhanced the overall myoplasmic calcium removal. in particular, the rate const ... | 1990 | 2394372 |
| behaviour of chemically modified sodium channels in frog nerve supports a three-state model of inactivation. | voltage clamp experiments were done on single myelinated nerve fibres of the frog, rana esculenta, with 10 mm tea+ in the external solutions to block potassium channels. sodium current inactivation was measured in tea-ringer solution and after treatment with anemonia sulcata toxin ii (5 microm), internal iodate (20/40 mm), glutaraldehyde (10 mm), chloramine-t (0.6 mm), and 2,4,6-trinitrophenol (1 mm). the diphasic inactivation time course, observed in untreated membranes, is slowed by all these ... | 1985 | 2409520 |
| effects of chemical modification of amino groups by two different imidoesters on voltage-clamped nerve fibres of the frog. | voltage clamped single nerve fibres of the frog rana esculenta were treated with the amino groups specific reagents ethyl acetimidate and isethionyl acetimidate. ethyl acetimidate is lipid soluble, relatively non-polar and can penetrate a membrane. isethionyl acetimidate is lipid-insoluble, polar and membrane-impermeant. treatment with ethyl acetimidate caused an irreversible reduction of na currents and a shift of the voltage dependence of the steady-state sodium inactivation, h infinity (e), i ... | 1985 | 2409524 |
| excitation contraction coupling in skeletal muscle: evidence for a role of slow ca2+ channels using ca2+ channel activators and inhibitors in the dihydropyridine series. | ca2+ current and tension have been simultaneously recorded from single twitch fibres of the semi-tendinosus of rana esculenta in a medium containing a physiological ca2+ concentration (1.8 mm). under appropriate conditions it can be shown that tension develops in two phases. the first is rapid and reaches its maximum before activation of the inward ca2+ current. the second phase is slower and with a time course which appears to be correlated with that of the inward current. nifedipine, a specifi ... | 1985 | 2409971 |
| effect of vasopressin on the permeability of non electrolytes across the skins of rana esculenta and bufo bufo. | maximal doses of vasopressin increase the permeability of the skins of bufo bufo and rana esculenta to urea, ethylene glycol, glycerol, erythritol, beta-alanine, leaving virtually unmodified that of mannitol and antipyrine. these results demonstrate that the response to vasopressin is quite different in amphibian skins as compared to the bladders. a careful analysis of the effects of vasopressin on non-electrolyte permeability as a function of their molecular weight demonstrates that hormone eli ... | 1985 | 2412508 |
| [effect of temperature on the interaction of gramicidin a and its dimer analog with the muscle fiber membrane]. | potassium conductance of single muscle fibres from rana esculenta was studied in isotonic k2so4 solution under constant current conditions using double sucrose gap method. at room temperature the channel formation by gramicidin was much faster than that of the synthetic head to head covalently linked gramicidin dimer. the increase of temperature by 8-10 degrees c resulted in a considerable rise of both dimer- and gramicidin-induced conductances. the effect was much greater than in the case of bi ... | 2014 | 2413902 |
| capsaicin in adult frogs: effects on nociceptive responses to cutaneous stimuli and on nervous tissue concentrations of immunoreactive substance p, somatostatin and cholecystokinin. | adult frogs (rana esculenta) were given subcutaneous injections of 10, 20, 30, 50 and 100 mg/kg capsaicin in sequential order over 5 days, or the vehicle only. the nociceptive thresholds to electrical, thermal and chemical stimuli were measured before, and 1, 5 and 24 h after each injection. capsaicin was followed by a dose-related reduction of nociceptive responses to all stimuli, but these effects lasted for only 1-5 h after the given injection. water/acetic extracts of undivided brains and sp ... | 1985 | 2418369 |
| effect of sodium on amiloride- and triamterene-induced current fluctuations in isolated frog skin. | the apparent association constants of two agents, amiloride and triamterene, that block the na-selective channel of apical membrane of frog skin are shown to decrease as the na concentration is increased in the apical bathing solution in isolated skin of the frog, rana temporaria, rana esculenta, and rana pipiens. these results were obtained in "normally polarized" skins. these effects were independent of the anion used (chloride or methylsulfate) or the cation used as the na substitute (tris, d ... | 1986 | 2420917 |
| regulation of intracellular sodium and ph by the electrogenic h+ pump in frog skin. | we have investigated the role of the electrogenic hydrogen ion pump in the regulation of intracellular sodium ion activity (aina) and intracellular ph (phi) in frog skin epithelial cells using double-barreled ion sensitive microelectrodes. when rana esculenta skin is mounted in an ussing chamber and bathed in 1 mm na2so4 buffered to ph 7.34 with imidazole on the apical side and in normal ringer on the serosal side, the apical addition of the carbonic anhydrase inhibitor ethoxzolamide (10(-4)m) b ... | 1986 | 2423951 |
| impairment of na+ transport across frog skin by tl+: effects on turnover, area density and saturation kinetics of apical na+ channels. | na+ transport across abdominal skin of the frogs, rana temporaria and rana esculenta was followed by measuring na+-dependent short-circuit, current (ina) kinetics and ina fluctuations induced by triamterene, a diuretic. exposure of the skin to serosal tl+ led to a pronounced and irreversible drop in ina and ina-blocker noise. at low serosal tl+ concentrations, we observed mainly a decrease in the apparent michaelis constant for ina saturation while, at larger [tl+], the maximal ina dropped irrev ... | 1986 | 2428005 |
| inhibition of sodium for sodium exchange by phlorizin in frog sartorius muscle. | the effects of phlorizin (2 x 10(-3) mol x l-1) on the na transport of frog (rana esculenta) sartorius muscle were investigated in glucose-free medium. phlorizin decreased the rate coefficient of 24na efflux by about 40%. the degree of inhibition was comparable to that caused by ouabain (10(-4) mol x l-1). phlorizin could evoke a further reduction in the 24na efflux also in the presence of ouabain. the intracellular na content of the phlorizin-treated muscles remained unchanged, in contrast to a ... | 1986 | 2428205 |
| effects of standard diuretics and rph 2823 on transepithelial na+ transport in isolated frog skin. | short-circuit current (scc) techniques were used to monitor the effects of various diuretic agents on na+ transport in isolated frog skin, a model for the late distal tubule and the collecting duct of the mammalian kidney. acetazolamide, hydrochlorothiazide, torasemide, and ethacrynic acid did not affect sodium transport (as indicated by the scc) or transepithelial electrical resistance when added either to the apical (outer) or to the inner (basolateral, corial) bathing solution of the tissue. ... | 1986 | 2429018 |
| acid secretion through the rana esculenta skin: involvement of an anion-exchange mechanism at the basolateral membrane. | kinetic and electrophysiological studies were carried out to characterize the efflux of hco3- (or oh-) across the basolateral membrane of the proton-secreting cells of the frog skin epithelium bathed with dilute saline mucosal solutions. in control conditions, the acidification of the mucosal solution (jnh+) was correlated directly with serosal alkalinization. cl- substitution in the serosal ringer (by gluconate or methylsulphate ions) induced an inhibition of proton excretion (70% inhibition). ... | 1986 | 2432250 |
| purification and characterization of a beta-toxin from the venom of the african scorpion leiurus quinquestriatus. | the venom of the african scorpion leiurus quinquestriatus was subjected to high-performance ion-exchange chromatography. among a large number (greater than 25) of small proteins and other substances, a protein component of approx. 6500 da was purified. the effect of this toxin was tested on single myelinated nerve fibres of the frog rana esculenta. toxin concentrations less than 10 nm produced clear effects. activation rather than inactivation of the voltage-dependent sodium channel was strongly ... | 1987 | 2436942 |
| action of benzocaine on sodium channels of frog nodes of ranvier treated with chloramine-t. | single myelinated nerve fibres of the frog rana esculenta were voltage clamped in solutions containing 10 mm tea to block potassium channels. reduction of peak ina was measured after equilibrating the membrane in solution containing benzocaine between 0.025 and 2.0 mm. a hill plot of this effect revealed a slope nh approximately 1 between 0.25 and 1.0 mm but showed deviations for the lowest concentrations (nh less than 1) and the highest concentration (nh greater than 1). treatment with 0.6 mm c ... | 1987 | 2442701 |
| periodate treatment reduces the tetrodotoxin-sensitivity of voltage-gated na+ channels. | (1) voltage-clamped nerve fibres of the frog rana esculenta were treated with periodate in the extracellular solution. (2) periodate treatment irreversibly reduced the effect of tetrodotoxin (ttx) on the na+ currents. (3) the effect of saxitoxin (stx) was also reduced but less than that of ttx. (4) the presence of stx during the application of periodate to the nerve fibre almost completely prevented the effect of the chemical reagent on the ttx sensitivity of the na+ channels. (5) the reduction ... | 1988 | 2450584 |
| na transport stimulation by novobiocin: transepithelial parameters and evaluation of ena. | the action of the antibiotic novobiocin on transepithelial na transport was studied in isolated skins obtained from two different frog species. in rana esculenta addition of novobiocin to the outer bath (1 mm) resulted in a sustained and reversible stimulation of the short-circuit current, transepithelial potential, and transepithelial conductance. similar, though more variable and much less pronounced changes were observed in rana temporaria. in the presence of amiloride (0.1 mm) novobiocin had ... | 1988 | 2454448 |
| the high molecular weight and the low molecular weight acid phosphatases of the frog liver and their phosphotyrosine activity. | 1. two molecular weight classes of non-specific acid phosphatases (acpases) (3.1.3.2) are present in the frog (rana esculenta) liver: a higher molecular weight (hmw) of mr 140,560 and a lower molecular weight (lmw) of mr 38,180 enzyme. 2. the lmw acpase was described earlier and the hmw acpase of optimum ph 4.8 is shown to be a l(+)-tartrate sensitive, thermolabile, dimeric glycoenzyme slightly activated by dtt. 3. the hmw and the lmw acpases exhibit activity for phosphotyrosine which showed sim ... | 1988 | 2456178 |
| effect of theophylline on the apical sodium and chloride permeabilities of amphibian skin. | 1. the effects of theophylline (1 mmol/l) on the sodium transport (short-circuit current, isc) and transepithelial conductance (gtotal) through toad (bufo viridis) and frog (rana temporaria and rana esculenta) skin were investigated. 2. in toad skin incubated with nitrate ringer solution on the apical side, theophylline induced an increase in isc similar to that in frog skin bathed with chloride ringer solution. 3. the increase in isc could be attributed to recruitment of sodium channels, withou ... | 1988 | 2457697 |
| electrophysiological analysis of sodium-transport in the colon of the frog (rana esculenta). modulation of apical membrane properties by antidiuretic hormone. | sodium transport and apical bioelectrical membrane properties were investigated in frog colonic epithelium in the absence and presence of the antidiuretic hormone arginine-vasotocin (avt). apical na-permeability and intracellular na-activity were evaluated by analysis of current-voltage relationships in the serosally k-depolarized tissue. tissue- and apical membrane capacitance were measured by voltages step analysis. the frog colon was found to be a tight epithelium with a transepithelial resis ... | 1988 | 2457866 |
| effects of oxymorphazone in frogs: long lasting antinociception in vivo, and apparently irreversible binding in vitro. | oxymorphazone (at doses of 50-200 mg/kg) was found to be a relatively weak antinociceptive drug in intact frog (rana esculenta) when acetic acid was used as pain stimulus. frogs remained analgesic for at least 48 hrs following oxymorphazone (200 mg/kg) administration. the ligand increased the latency of wiping reflex in spinal frogs too. these effects were blocked by naloxone. in equilibrium binding studies (3h)oxymorphazone had high affinity to the opioid receptors of frog brain and spinal cord ... | 1989 | 2472540 |
| dc injection alters spontaneous otoacoustic emission frequency in the frog. | a permanent wire electrode was implanted in the inner ear of the green frog (rana esculenta). through this electrode direct current was delivered to the inner ear fluid of the frog, during recording of a spontaneous otoacoustic emission (soae). both soae frequency and amplitude turned out to depend on dc level and polarity. possible explanations for the observed phenomena are given, based on a dissipative limit-cycle oscillator model for soae generation, and the assumption that soae frequency de ... | 2008 | 2478517 |
| quantitative stimulus-response studies on sustained ganglion cells in the frog retina. | "sustained" visual units, i.e. nonerasable (r1) and erasable (r2) units as commonly described, were recorded in the superficial layers of the rostral optic tectum of rana esculenta and their neuronal activity (expressed as the mean firing frequency r) was quantitatively analyzed. the mean value of the exponent alpha of the velocity function of the erasable r1 units was found to be 0.46 and the constant k to be about 24.7. the optimal stimulus diameter was equal to 2.6 deg. for the whole populati ... | 1989 | 2487082 |
| melanogenesis in the pigment cells of rana esculenta l. liver: evidence for tyrosinase-like activity in the melanosome protein fraction. | this work demonstrates the presence of a tyrosinase-like activity in the pigment cells of frog rana esculenta l. liver. the activity was evidenced in the protein melanosome fraction extracted with differential centrifugation methods. the study of this activity, carried out with spectrophotometric methods, indicates 1) the system presents the characteristics of an allosteric enzyme; 2) the grade of cooperativity shows oscillations going from negative cooperativity toward the substrate, evident in ... | 2016 | 2497447 |
| 76 and 14 kda polypeptides, two major components released from amphibian urinary bladder epithelium. purification and characterization. | exocytotic processes play a major role in the hormonal control of water permeability in the amphibian urinary bladder. different treatments such as antidiuretic hormone (adh) stimulation, incubation with phorbol ester or mild detergent and mechanical stretch of the bladder, consistently induce a liberation of two major polypeptides of 76 and 14 kda molecular mass into the luminal medium. each of these polypeptides represents 3 to 5% of the total protein of epithelial cell homogenates and 20 to 5 ... | 1989 | 2503379 |
| retino-retinal projections in three anuran species. | in juvenile and adult xenopus laevis, in adult bufo marinus and rana esculenta frogs retino-retinal projections were traced by filling the central stump of one optic nerve, cut 2-3 mm from the eye, with horse-radish peroxidase (hrp) or cobaltic-lysine complex (clc). the presence of retino-retinal projections was confirmed in all 3 species both in the juvenile and the adult. up to 12 ganglion cells per retina were found to be filled retrogradely with hrp together with optic axons filled anterogra ... | 1989 | 2510094 |
| a gonadotropin releasing hormone analog induces spermiation in intact and hypophysectomized frogs, rana esculenta. | the sperm-releasing activity of a gonadotropin releasing hormone (gnrh) agonist, buserelin (gnrh) and hypophysis homogenate (pd) preparations was studied in intact and hypophysectomized (pdx) frogs, rana esculenta. in addition, human chorion gonadotropin (hcg) was tested in pdx animals, and gnrh antagonist (gnrha) treatments were carried out in intact and pdx animals, in combination with the hormonal injections. gnrh or pd treatments were able to elicit spermiation in intact and pdx animals. whi ... | 1989 | 2513222 |
| [the reaction of tadpoles of the common toad (bufo bufo l.) to chemical signals from individuals of their own and other species]. | in behavioral experiments, toad tadpoles-recipients chose between two parts of test aquarium with chemical signals of donor tadpoles of the same or different (rana esculenta) species. the youngest studied tadpoles (43-45 stages) preferred the part of the aquarium with chemical cues from sibs as compared to non-sibs. no reliable difference in "non-sibs: water" system was observed. in "tadpoles of the same species: tadpoles of the other species" system, recipient tadpoles chose "their" part of the ... | 1989 | 2515677 |
| functional aspects of calcium transport in sarcoplasmic reticulum vesicles derived from frog skeletal muscle treated with saponin. | to study the physiological aspects of the excitation-contraction cycle, saponin (10-100 micrograms ml-1) was used as a skinning agent on muscle and sarcotubular vesicles derived from fast muscles (sartorius and tibialis anterior) of rana esculenta. the vesicles showed similar ca2+-atpase activity and similar protein profiles carried out by sds-page. calcium transport in untreated vesicles and those treated with different concentrations of saponin seemed to have the same quantitative and qualitat ... | 1989 | 2527869 |
| lithium decreases retinal melatonin levels in the frog. | the effect of the acute i.p. administration of lithium chloride (1 mg/kg) and of haloperidol (1 mg/kg) on retinal melatonin levels was studied in light-adapted and dark-adapted frogs of the species rana esculenta. two hours following drug administration, animals were killed by decapitation and a single retina from each frog was collected and homogenized in 1 ml of chilled 0.1 n hcl. after centrifugation, the ph of the supernatant was adjusted to 7.0. melatonin was extracted by diethylether and a ... | 1989 | 2538784 |
| diazepam effects on frog skin cyclic nucleotide phosphodiesterase. | 1. the activities of camp phosphodiesterases (camp-pde) have been measured in the homogenate of the skin of rana esculenta. 2. the tissue possesses two distinct enzymes: a "low" km pde (km = 0.42 x 10(-6) m; vmax = 16 pmol/mg protein/min) and a "high" km pde (km = 180 x 10(-6) m; vmax = 2853 pmol/mg prot/min). only the "high" km form is stimulated by calcium. 3. diazepam (1-0.5 mm) significantly inhibits both enzymes, the inhibition being of competitive type. | 1989 | 2545510 |
| cytochemical localization of alkaline phosphatase and na+, k+-atpase activities in the blood-brain barrier of rana esculenta. | the ultrastructural distribution of alkaline phosphatase and na+, k+-atpase on the brain capillaries in rana esculenta was investigated. alkaline phosphatase activity appears both on the luminal and abluminal walls of the endothelial capillary cells; na+, k+-atpase is, instead, only present on the abluminal side. this different enzymatic distribution indicates that endothelial cells of the brain capillaries are polarized and the luminal and abluminal endothelial membranes are functionally differ ... | 1989 | 2547356 |
| voltage and temperature dependence of normal and chemically modified inactivation of sodium channels. quantitative description by a cyclic three-state model. | (1) voltage clamp experiments were done on single myelinated nerve fibres of the frog, rana esculenta, with 10 mm tea in the external solution to block potassium channels. (2) the potential dependence of normal sodium current inactivation was studied over a potential range of v = -50 mv to 80 mv. at depolarizations (v greater than or equal to 30 mv) inactivation is diphasic. the relative contribution of the fast phase increases from 0.4 at v = 30 mv to 0.96 at v = 80 mv. at resting potential (v ... | 1989 | 2550880 |
| distribution of renal calcitonin binding sites in mammalian and nonmammalian vertebrates. | calcitonin (ct), the hypocalcemic hypophosphatemic hormone, is present in many vertebrate species. the principal target organs for ct are, in mammals, kidney and bone, and in fish, bone and gill. we have investigated the presence of renal calcitonin binding sites in a fish (salmo gairdneri), two amphibians (bufo bufo and rana esculenta), two reptiles (pseudemys scripta and gekko gecko), and two birds (gallus domesticus and cothurnix japonica). we compared their distribution to a mammal, the rat ... | 1989 | 2555248 |
| autoregulation of apical sodium entry in the colon of the frog (rana esculenta). | 1. na transport (ina) in the k-depolarized colon of the frog was investigated by electro-physiological current-voltage analysis. 2. ina and the intracellular na activity [(na)c] increased with increasing mucosal na concentration ([na]m), whereas the apical na-permeability (pnam) and the transepithelial resistance (rt) decreased. 3. the results are consistent with a na self-inhibition mechanism; however, a feedback inhibition of ina by intracellular na must also be considered. | 1989 | 2569375 |
| effect of n-ethylmaleimide treatment on naloxone binding in frog brain membranes. | specific binding of (3h) naloxone to opioid receptors in frog (rana esculenta) brain membranes was irreversibly inactivated by the sulfhydryl group alkylating agent n-ethylmaleimide (nem). saturation analysis of (3h) naloxone binding revealed a marked reduction in the number of ligand binding sites after n-ethylmaleimide treatment. pretreatment of the membranes with unlabelled opioid ligands, i.e. naloxone, morphine, or the kappa selective dynorphin (1-13), and sodium ions resulted in considerab ... | 1989 | 2575315 |
| a voltage-dependent k+ channel controlling the membrane potential in frog oocytes. | full-grown frog ovarian oocytes (rana esculenta), were voltage clamped with a conventional two-microelectrode system. depolarizations from a holding potential of--60 mv produced slowly developing outward currents. two-step clamp experiments showed that, in ringer's solution, this current has a reversal potential at about--84 mv. substitution of either sodium or chloride with impermeant ions in the external solution did not alter significantly the activation of the current nor its reversal potent ... | 1985 | 2580268 |
| substance p-like immunoreactivity in the frog dorsal root ganglia. | the distribution of substance p-like immunoreactivity was studied in the thoracic dorsal root ganglia of the frog rana esculenta by immunohistochemistry. substance p-like immunoreactivity was contained in approximately 50% of primary sensory neurons. the immunoreactive fibers arising from the cell bodies are collected in small bundles within the ganglia neuropil before entering the central and peripheral roots. | 1985 | 2580735 |
| [experimental demonstration of the annual characteristic of the lines of arrest of skeletal growth in rana esculenta (amphibia, anura)]. | different vital fluorescent labelling (tetracycline, calcein, xylenol orange, alizarine red s) have been injected in a series of young growing green frogs, caught near paris and kept for 2 years in captivity under conditions quite similar to natural ones. the study of femur and phalanx has been carried out by ground sections observed in uv light and then colored with hematoxyline. the comparison between uv and transmitted light observations shows that the arrested growth lines are annual, laid d ... | 1985 | 2581679 |
| electrogenic active proton pump in rana esculenta skin and its role in sodium ion transport. | kinetic and electrophysiological studies were carried out in the in vitro rana esculenta skin, bathed in dilute sodium solution, to characterize the proton pump and coupling between sodium absorption (jna+n) and proton excretion (jh+n). jna+n and jh+n were both dependent on transepithelial potential (psi ms); hyperpolarizing the skin decreased jna+n and increased jh+n; depolarization produced the opposite effects. amiloride (5 x 10(-5) m) at a clamped psi ms of +50 mv inhibited jna+n without aff ... | 1985 | 2582114 |
| granulopoiesis in tadpoles of rana esculenta. ultrastructural observations on the morphology and development of heterophil and basophil granules. | the morphology and development of heterophil and basophil granules from the trunk kidneys of rana esculenta tadpoles were studied at the electron microscopic level. cells of the heterophils series contain granules displaying either spheroid profiles with homogeneous content (type a), or elongate profiles with a crystalloid interior (type b). type a granules apparently originate directly from golgi-derived vesicles, which, gaining slightly in size and density, transform into the mature granules. ... | 2008 | 2606765 |
| granulopoiesis in tadpoles of rana esculenta. ultrastructural observations on the developing granulocytes and on the development of eosinophil granules. | the morphology and development of the granules of developing eosinophils present in the trunk kidneys of rana esculenta tadpoles has been studied at the ultrastructural level. during the differentiation of eosinophil granulocytes a single and morphologically unique population of cytoplasmic granules is present. fully developed granules are spherical, membrane-limited, and have a dense and homogeneous content. eosinophil granules have been traced back to golgi-derived vacuoles which fuse and form ... | 1989 | 2606785 |
| biochemical investigation of the rana esculenta complex in the kis-balaton nature reserve, hungary. | in this study it has been proved by page of serum proteins that all the three members of the rana esculenta complex occur in the kis-balaton nature reserve (hungary). on the basis of the ldh isoenzyme pattern which is characteristic in green frogs we could distinguish all three variations of r. ridibunda and r. lessonae and one type of r. esculenta. the mobility of serum albumins on sds-page implies that the r. esculenta comes from hybridization of the two other species. the page methods provide ... | 1989 | 2633579 |
| molecular forms of immunoreactive gonadotropin-releasing hormone in hypothalamus and testis of the frog, rana esculenta. | the hypothalamus and the testis of the frog, rana esculenta, contain gonadotropin-releasing hormone (gn-rh)-like peptides which are recognized by an antiserum raised against mammalian gn-rh. two molecular forms which coelute with synthetic chicken ii and salmon gn-rh from reverse-phase hplc were distinguished in the hypothalamus. a single peak coeluting with synthetic chicken ii gn-rh was present in the testis. | 1989 | 2676699 |
| spontaneous otoacoustic emissions in the european edible frog (rana esculenta): spectral details and temperature dependence. | spontaneous otoacoustic emissions were recorded in 41 ears of 29 european edible frogs (rana esculenta). emission frequencies ranged from 450 to 1350 hz. the distribution of frequencies shows two distinct populations: one above and one below 1 khz. with one exception, a maximum number of two emissions were recorded per ear, each in a different population. an amplitude distribution of a frog emission was sampled, from which it was concluded that the emission is generated by an active oscillator. ... | 1989 | 2691473 |
| the lower molecular weight acid phosphatase from the frog liver: isolation of homogeneous acpase iii and iv representing glycoforms with different bioactivity. | 1. acpase iii and acpase iv, the major enzyme forms of the lmw acpase of the frog (rana esculenta) liver were resolved and purified to homogeneity. 2. acpase iii and iv showed a single protein band on sds-page corresponding to a mol. wt (mr) of about 35,000. the mr of the native enzyme forms were 33,200 (gel electrophoresis) and 38,200 +/- 5000 (gel filtration). this indicates that they are monomeric proteins sharing the same protein molecule. 3. acpase iii and iv differ essentially in thermosta ... | 1989 | 2784366 |
| distribution of proenkephalin-derived peptides in the brain of rana esculenta. | the immunocytochemical distribution of authentic proenkephalin-containing perikarya and nerve fibers in the brain of rana esculenta was determined with antisera directed toward different epitopes of preproenkephalin. the pattern of proenkephalinlike immunoreactivity was similar with antisera directed toward [met5]-enkephalin, [met5]-enkephalin-arg6, [met5]-enkephalin-arg6-phe7, [leu5]-enkephalin, and metorphamide; however, the intensity of the labelling varied depending on the target antigen. pr ... | 1989 | 2784450 |
| terminal nerve sprouting at the frog neuromuscular junction induced by prolonged tetrodotoxin blockade of nerve conduction. | the effects of a prolonged blockade of nerve conduction by tetrodotoxin on frog motor innervation were studied in the cutaneous pectoris muscle of rana esculenta. prolonged nerve blockade (up to 22 days) was obtained by repeated subperineural injections of tetrodotoxin. changes in morphological parameters of neuromuscular junctions were investigated in muscles after staining with a combined cholinesterase-silver method. in addition, changes in the incidence of polyneuronal innervation were inves ... | 2009 | 2785162 |
| quantitative studies on ipsilateral type 2 retinotectotectal (irtt) units in frogs: homologies with r3 ganglion cells. | contralateral and ipsilateral responses from deep layers of the rostral neuropil of the optic tectum of rana esculenta were recorded extracellularly and quantitatively analyzed. effects of the velocity and diameter of the stimulus on the neuronal response (measured as the mean firing frequency, r) were mainly tested in this work. 1. among the population of changing contrast or event ganglion cells, r3-like units (with a weak response to background off-on stimulation) were defined in addition to ... | 1989 | 2785209 |
| calcium-dependent chloride transient currents in the immature oocyte of the frog, rana esculenta. | transient currents of chloride were studied in the plasma membrane of immature frog oocyte in voltage clamp conditions. the transients appeared to be activated by an influx of ca2+ from the external medium. the mechanism leading to a surge of intracellular ca2+ concentration needed at least 30 sec before full recovery. it was inhibited by substituting ba2+ for ca2+ in the external medium, or in the presence of la3+, co2+ and cd2+, or when external na+ was replaced by li+. verapamil proved ineffe ... | 1989 | 2785786 |
| effects of a synthetic cationic polymer on sodium and potassium currents of frog nerve fibres. | (1) voltage-clamped nerve fibres of the frog rana esculenta were treated with the synthetic cationic polymer hexadimethrine bromide (hdm) [polybrene]. (2) 1 microm hdm irreversibly reduced ina to about 65% of its original size. the time to peak remained almost unaffected, while the decaying phase of the currents (for pulse potentials less than -10 mv) became accelerated. the size of ina was hardly reduced further even with a 1,000-fold higher concentration of hdm. (3) the cationic polymer hdm wa ... | 1989 | 2786187 |
| the distribution of gaba-like-immunoreactive neurons in the brain of the newt, triturus cristatus carnifex, and the green frog, rana esculenta. | the distribution of gamma-aminobutyric acid (gaba) immunoreactivity was studied in the brain of two amphibian species (triturus cristatus carnifex, urodela; rana esculenta, anura) by employing a specific gaba antiserum. a noteworthy immunoreactive neuronal system was found in the telencephalic dorsal and medial pallium (primordium pallii dorsalis and primordium hippocampi) and in the olfactory bulbs. in the diencephalic habenular nuclei there was a rich gabaergic innervation, and immunoreactive ... | 2009 | 2786752 |
| hydrins, hydroosmotic neurohypophysial peptides: osmoregulatory adaptation in amphibians through vasotocin precursor processing. | from neurointermediate pituitary glands of xenopus laevis and rana esculenta, previously unreported peptides termed hydrins, active on water permeability of frog urinary bladder and frog skin (brunn or "water-balance" effect), have been isolated and sequenced. these peptides seem to be derived from the pro-vasotocin-neurophysin precursor. hydrin 1, found in xenopus, has been identified as vasotocin c-terminally extended with the gly-lys-arg sequence; hydrin 2, found in rana, has been identified ... | 1989 | 2787509 |
| cholesterol metabolism in frog (rana esculenta) liver: seasonal and sex-related variations. | many aspects of lipid metabolism have been studied in amphibians, but seasonal lipid modulation in male and female frogs has not been investigated. we describe here the yearlong patterns of hepatic lipid content and enzyme activities related to cholesterol homeostasis, 3-hydroxy-3-methylglutaryl coenzyme a (hmg-coa) reductase activity and acyl coenzyme a:cholesterol acyltransferase (acat) activity in liver of the male and female frog, rana esculenta. lipid storage follows distinct seasonal patte ... | 1989 | 2787885 |
| the harderian gland of the frog, rana esculenta, during the annual cycle: histology, histochemistry and ultrastructure. | the harderian gland in rana esculenta has been studied during the annual cycle at the histological, histochemical and ultrastructural levels. the harderian gland has an acinar structure and is the only orbital gland in anuran amphibia. it develops at the medial corner of the orbit from the conjunctival epithelium at the premetamorphic stage. in the adult the glandular secretion reaches a maximum during the months of july and august, drops in september and resumes slowly from october onwards. the ... | 1989 | 2787983 |
| seasonal fluctuations of estrogen-binding activity in the testis of the frog, rana esculenta. | we have studied the annual cycle of estrogen-binding activity in the frog, rana esculenta, testis to evidence possible fluctuations. the testicular binding for [3h]estradiol-17 beta shows high affinities (cytosolic kd = 1.94 +/- 0.43 x 10(-9) m; nuclear kd = 2.72 +/- 1.20 x 10(-9) m) and low capacity (cytosolic: 7.56 +/- 0.66 fmol/mg protein; nuclear: 9.27 +/- 2.5 fmol/mg protein). nuclear-binding activity appears in spring concomitantly with the estradiol peak in plasma and testes, while, in th ... | 1989 | 2788594 |
| intratesticular feedback mechanisms in the regulation of steroid profiles in the frog, rana esculenta. | testosterone (t), 5 alpha-dihydrotestosterone (dht), estradiol-17 beta (e), and progesterone (p) were measured in the plasma of the frog, rana esculenta, during the annual cycle. moreover, in vitro experiments were carried out in order to investigate the local regulation of steroidogenesis. testosterone and dht showed high values during autumn and early spring and had a t/dht ratio which increased during summer, while e peaked in midspring, remaining at detectable values thereafter. progesterone ... | 1989 | 2792721 |
| isolation of large sheets of apical material from frog urinary bladder epithelial cells by freeze-fracture. | in the amphibian urinary bladder, water permeability is correlated with the insertion of intramembrane particle aggregates (impas) into the apical plasma membrane (am) of the granular cells. these aggregates are believed to contain water channels. characterization of the impas by comparing am fractions of antidiuretic hormone (adh)-treated and resting epithelia requires isolation and purification of am-rich material, free of other cytoplasmic aggregate-containing organelles, in both cases. a tec ... | 1989 | 2804463 |
| acid phosphatases from liver of rana esculenta. subcellular localization and partial characterization of multiple forms. | 1. four acid phosphatases (acpase i, ii, iii and iv) were found in the liver of the frog rana esculenta. 2. acpases i, ii, iii, and iv were associated with the microsomal, mitochondrial-lysosomal, nuclear and soluble fractions respectively and showed apparent molecular weights of about 240,000, 110,000, 38,000 and 17,000. 3. all the enzymes show acid ph optima, and similar km values for p-nitrophenylphosphate. 4. acpases i, ii, and iii hydrolyze most of the common phosphate esters whereas acpase ... | 1989 | 2805644 |
| assembly of the native heterodimer of rana esculenta tropomyosin by chain exchange. | rana esculenta tropomyosin assembles in vivo into a coiled-coil alpha helix from two different subunits, alpha and beta, which are present in about equal concentrations. although the native composition is alpha beta, a mixture of equal amounts of alpha alpha and beta beta is produced by refolding dissociated alpha and beta at low temperature in vitro. refolding kinetics showed that alpha alpha formed first and was relatively stable with regard to chain exchange below approximately 20 degrees c. ... | 1989 | 2814515 |
| evolutionary history of the hybridogenetic hybrid frog rana esculenta as deduced from mtdna analyses. | mtdna of the hybridogenetic hybrid frog rana esculenta from switzerland, austria, and poland was compared to mtdna of the parental species r. ridibunda and r. lessonae using electrophoretic analysis of restriction enzyme fragments. two mtdna phenotypes, with 3.4% sequence divergence, are present in r. lessonae: type c is found in poland, and type d is found in switzerland. rana ridibunda from poland has either of two mtdna phenotypes: type a is the typical ridibunda mtdna, and type b is a lesson ... | 1986 | 2832687 |
| [effect of several cyclic amp phosphodiesterase inhibitors on the permeability of the skin of rana esculenta]. | 1987 | 2833913 | |
| hypothalamus-hypophysis and testicular gnrh control of gonadal activity in the frog, rana esculenta: seasonal gnrh profiles and annual variations of in vitro androgen output by pituitary-stimulated testes. | the binding of a gonadotrophin-releasing hormone (gnrh) long acting analog (gnrha), d-ser (but)6,pro9-net gnrh (hoe 766), to pituitary and testicular extracts and the presence of gnrh-like material in testes and hypothalamuses were measured in the frog, rana esculenta. also, the cellular localization of immunoreactive gnrh was investigated in testes by immunohistochemical staining. furthermore, lyophilized preparations of pituitary crude homogenates from animals caught monthly were tested in vit ... | 1988 | 2836262 |
| fused cells of frog proximal tubule: ii. voltage-dependent intracellular ph. | experiments were performed in intact proximal tubules of the doubly perfused kidney and in fused proximal tubule cells of rana esculenta to evaluate the dependence of intracellular ph (phi) on cell membrane potential applying ph-sensitive and conventional microelectrodes. in proximal tubules an increase of the k+ concentration in the peritubular perfusate from 3 to 15 mmol/liter decreased the peritubular cell membrane potential from -55 +/- 2 to -38 +/- 1 mv paralleled by an increase of phi from ... | 1988 | 2838635 |
| melanosomes from liver and skin of rana esculenta l. a comparative chemical study. | 1. melanosomes from skin and liver of rana esculenta l. have been isolated and some chemical properties of the relevant melanin and protein components were compared. 2. in both cases the pigments show spectroscopic (esr) and chemical characteristics similar to those of eumelanins. the melanin content in skin melanosomes is higher than in the liver counterparts. 3. amino acid patterns of the two protein components are different in their quantitative composition and both are characterized by high ... | 1988 | 2842111 |
| noise analysis of camp-stimulated na current in frog colon. | the effects of oxytocin and camp on the electrogenic na+-transport in the short-circuited epithelium of the frog colon (rana esculenta, rana temporaria) were investigated. oxytocin (100 mu.ml-1) elevated the short-circuit current (isc) transiently by 70% whereas camp (1 mmol.l-1) elicited a comparable sustained response. the mechanism of the natriferic action of camp was studied by analysing current fluctuations through apical na+-channels induced by amiloride or cdpc (6-chloro-3,5-diaminopyrazi ... | 1988 | 2850532 |
| [effect of dihydropyridines on cation transport across the skeletal muscle membrane in the frog]. | 2,6-dimethyl-3,5-dimethoxycarbonyl-4-(o-difluromethoxyphenyl)- 1,4-dihydropyridine (ryodipine) blocks ca-channels in phasic muscle fibres from ileofibularis and semitendinosus muscle of rana esculenta. ryodipine and some other newly synthesized dihydropyridines (10(-7)-10(-4) m) exerted a slight, if any, effect on the steady-state of potassium chord conductance in isotonic k+-sulfate solution. the effluxes of potassium and rubidium from the sartorius muscle of rana temporaria also remained uncha ... | 1988 | 2854317 |
| the effect of alternariol mycotoxin (aoh) on active sodium transport across frog skin (rana esculenta). | 1988 | 2854477 | |
| effect of aminoglycoside antibiotics on sodium transport across the rana esculenta urinary bladder. | the aminoglycoside antibiotics inhibit the short circuit current (s.c.c.) in the urinary bladder of rana esculenta. this effect is due to a direct inhibition on the sodium pump; adh or db-ampc are not able to reverse the inhibition of the sodium current, but are effective in stimulating the urea fluxes in the presence of antibiotics. in correlation with the number of the nh+2 groups in the antibiotic molecule there is a different pattern of inhibitory effect, i.e. neomycin greater than gentamyci ... | 1985 | 2861057 |
| arylsulphatase activity and cerebroside sulphates in the frog oviduct during the reproductive cycle. | the presence of arylsulphatase a and cerebroside sulphates in different tracts of rana esculenta oviduct during different phases of the reproductive cycle were investigated by histochemical and biochemical procedures. the results indicate that enzyme activity shows seasonal fluctuations connected with the phase of the sexual cycle. the concentrations of cerebroside sulphates (the natural substrates of arylsulphatase a) is related to the activity of this hydrolytic enzyme. the role of arylsulphat ... | 1987 | 2884199 |
| antagonistic actions of prostaglandins e2 and f2 alpha on the isolated lungs of the frog, rana esculenta l. | isolated lungs of the frog, rana esculenta l., when incubated in amphibian ringer solution for 30 min, produced a prostaglandin e2-like substance (27.1 +/- 3.8 ng/g w.w.), as determined by bioassay on the isolated rat stomach strip. the release of pge2-like substance from skin, heart and bowel is also reported. the activity of synthetic prostaglandins e2 (pge2) and f2 alpha (pgf2 alpha) on the muscular contractility of frog isolated lungs was investigated: pge2 and pgf2 alpha relaxed and contrac ... | 1987 | 2885133 |
| arylsulphatase activity in the oviduct of the frog rana esculenta. i. oestradiol-induced changes following ovariectomy and hypophysectomy. | the effects of oestradiol treatment on arylsulphatase activity in the frog oviduct are reported. oestradiol-induced changes were also investigated in ovariectomized and hypophysectomized animals. under all the experimental conditions, hormonal treatment causes an increase in enzyme activity. this can be observed biochemically and also histochemically on frozen sections. hypotheses are advanced to explain fluctuations in arylsulphatase activity. | 1987 | 2885297 |
| evolution of neurotransmitter-related markers in the vertebrate telencephalon. comparative microchemical study in discrete brain regions of a frog and a turtle. | 1. neurochemical markers related to cholinergic, gabaergic and glutamatergic/aspartatergic neurotransmission have been measured in telencephalic areas obtained by microdissection from frog (rana esculenta) and turtle (pseudemys scripta elegans) brain. 2. in both species, pallial areas showed remarkably higher levels of synaptosomal d-3h-aspartate high affinity uptake than basal regions. conversely, striatal and septal areas possessed higher levels of the gabaergic marker glutamate decarboxylase ... | 1988 | 2899002 |
| selective protection of benzomorphan binding sites against inactivation by n-ethylmaleimide. evidence for kappa-opioid receptors in frog brain. | selective binding of [3h]bremazocine and [3h]-ethylketocyclazocine to kappa-opioid receptor sites in frog (rana esculenta) brain membranes is irreversibly inactivated by the sulfhydryl group alkylating agent n-ethylmaleimide (nem). pretreatment of the membranes with kappa-selective compounds [ethylketocyclazocine (ekc), dynorphin (1-13), or u-50,488h] but not with [d-ala2,n-me-phe4,gly5-ol]enkephalin (dago; mu specific ligand) or [d-ala2,n-me-phe4,gly5-ol]enkephalin (dadle; delta specific ligand ... | 1988 | 2900875 |
| lack of effect of rat atrial natriuretic factor (ranf) on the renal function in frogs. | 1. the aim of the present experiments was to examine the question whether the rat atrial natriuretic factor (ranf 1-28) could alter the fractional excretion of sodium (fena) and other solutes in the frog (rana esculenta). 2. although experiments were performed throughout the year possible seasonal changes in the animals were considered in particular. 3. in all frogs, a hypotonic diuresis was induced. 4. under these conditions in winter frogs, the control fena was 8.8 +/- 5.8% (15) [means +/- sd ... | 1988 | 2901317 |
| fat body involvement in vitellogenin fate in the green frog, rana esculenta. | 1. since, in rana esculenta, fat bodies contain vitellogenin, the present study was performed in order to determine whether or not fat bodies are involved in the fate of vitellogenin. 2. the experiment of november shows that fat body excision provokes plasma vitellogenin increase even in animals treated with estradion-17 beta + pituitary crude homogenate (as compared with relative control). the same picture has been shown in the april experiment. 3. the result on protein-bound phosphate in ovari ... | 1988 | 2904328 |
| effects of gramoxone and cooling on the antioxidant enzymes of frog (rana esculenta). | the effects of paraquat, the active ingredient of gramoxone, were studied on frogs (rana esculenta) kept at 4 degrees c or 20 degrees c, to establish its effects on the survival, the antioxidant enzyme system and the lipid peroxidation of the tissues (liver and lung). the lower temperature was found to increase the survival. the activities of the antioxidant enzymes were decreased or not influenced by the ld50 of paraquat at the lower temperature, whereas the ld100 often resulted in a significan ... | 1985 | 2951952 |
| dermal tracts in frog skin: fibronectin pathways for cell migration. | the dermis of the frog skin (rana esculenta) displayed a remarkable organization of vertical and horizontal tracts. vertical thick tracts connected the dermal stratum spongiosum with the subcutaneous tissue. horizontal thin tracts were found alongside and contiguous to them. the thick tracts were sheathed by collagen fibrils of the stratum compactum which were vertically oriented (i.e. parallel to the axes of the tracts) according to the horizontal and orthogonal arrangement of the collagen bund ... | 1987 | 2955840 |
| isolation of terminal cisternae of frog skeletal muscle. calcium storage and release properties. | sarcoplasmic reticulum (sr) terminal cisternae (tc) of frog (rana esculenta) fast-twitch skeletal muscle have been purified by isopycnic sucrose density gradient centrifugation. biochemical characteristics and ca2+ release properties have been investigated and compared to those of the homologous fraction of rabbit skeletal muscle tc. the frog sr fraction obtained at the 38/45% sucrose interface appears to be derived from the terminal cisternae region as judged by: (a) thin section electron micro ... | 1988 | 2968342 |
| effect of gaba and its antagonists, bicuculline and picrotoxin, on nerve cell discharges of the photosensory pineal organ of the frog, rana esculenta. | the effect of gamma-aminobutyric acid (gaba) and its antagonists, bicuculline and picrotoxin, was studied on pineal neurons of the frog, rana esculenta. the drugs were applied by microiontophoresis while monitoring the spontaneous activity and light-evoked responses of electrophysiologically identified achromatic (luminance) neurons of the pineal organ. almost all neurons investigated were sensitive to gaba. the inhibitory action was characterized by its rapid onset and its reversibility. the ga ... | 1985 | 2986761 |
| a gonadotropin-like thermostable peptide, prepared from bovine anterior pituitary, inducing spermiation in the frog rana esculenta (l.) and binding to a rat ovarian fsh receptor. | a thermostable peptide, inducing sperm release in rana esculenta l. and having immunological properties which resemble those of the gonadotropins but nonidentical with any one of the gonadotropins or their subunits, has been prepared from pars distalis of bovine anterior pituitaries by means of acetic acid extraction, heating, ethanol precipitation, and reverse-phase high-performance liquid chromatography (hplc). during the purification, the biological activity was regularly followed by means of ... | 1985 | 3000863 |
| hydrodynamic parameters of opioid receptors from frog brain. | active opioid receptors were solubilized from frog (rana esculenta) brain membranes using 1% digitonin. the solubilized preparation was sedimented in sucrose density gradient and applied to sepharose-6b column. in the ultracentrifugation experiments, two distinct molecular forms of the opioid receptors were observed with apparent s20, w values of 15.7 and 10.8 s. the estimated molecular weights were 470 and 180 kd. the stokes radii of the two separate forms were determined by gel filtration and ... | 1986 | 3005907 |
| trifluoperazine stimulated sodium transport by increased prostaglandin e2 synthesis in isolated frog skin (rana esculenta). | addition of trifluoperazine (tfp) to the inside bathing solution of the isolated frog skin resulted in a biphasic increase in the short-circuit current (scc). the na+-flux measurements showed that the tfp-induced increase of scc was accounted for by active sodium transport. the intracellular voltage in short circuited skins changed after addition of tfp (100 microm) from a control value of -80.9 +/- 0.8 to -66.2 +/- 1.0 mv (n = 8). this depolarization indicates that tfp acts by increasing the na ... | 1986 | 3014818 |
| mauthner neurons survive metamorphosis in anurans: a comparative hrp study on the cytoarchitecture of mauthner neurons in amphibians. | giant medullary neurons were revealed in adult xenopus laevis and rana esculenta following hrp injections to the spinal cord. these neurons were identified as mauthner neurons because (1) they have the same position and orientation as the larval mauthner neurons, i.e., they lie at the level of the viiith nerve root. (2) they have two large dendritic trees that for each species are similar to those of the larval mauthner neurons, (3) they are clearly distinguishable from other large reticular neu ... | 1986 | 3081602 |