Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| the probability of quantal secretion at release sites in different calcium concentrations in toad (bufo marinus) muscle. | 1. the number of quanta secreted from visualized release sites along terminal branches at toad (bufo marinus) neuromuscular junctions in different extracellular concentrations of calcium ions. [ca2+]o, and during facilitation was determined. terminal branches were visualized by prior staining with the fluorescent dye, 3-3 diethyloxardicarbocyanine iodide (dioc2(5)). 2. increasing [ca2+]o between 0.25 and 0.4 mm gave a similar proportional increase in the mean quantal content of the end-plate pot ... | 1989 | 2576063 |
| insulin and igf i receptor-mediated na+ transport in toad urinary bladders. | we compared the concentration dependence of insulin- and insulin-like growth factor i (igf i)-stimulated na+ transport with ligand-receptor affinities in the urinary bladder of the toad bufo marinus. threshold, half-maximal, and maximal natriferic concentrations of both peptides were approximately 0.1, 1, and 10 nm, respectively. amiloride, but not ethyl isopropyl amiloride, (10(-5) m), abolished na+ transport. maximal responses to either peptide rendered the tissue insensitive to challenge with ... | 1989 | 2552816 |
| steroid metabolism determines mineralocorticoid specificity in the toad bladder. | edwards et al. (c. r. w. edwards, p. m. stewart, d. burt, l. brett, m. a. mcintyre, w. s. sutanto, e. r. de kloet, and c. monder, lancet 2: 986-989, 1988) proposed that 11 beta-hydroxysteroid-dehydrogenase (11 beta-ohsd) plays a key role in the kidney by converting glucocorticoids (cortisol or corticosterone), which display a high affinity for type 1 mineralocorticoid receptors, into their inactive metabolites (cortisone or 11-dehydroxy-corticosterone), thus preventing their illicit occupation o ... | 1989 | 2508490 |
| the effects of vagal stimulation and applied acetylcholine on the sinus venosus of the toad. | 1. the effects of vagal stimulation and applied acetylcholine were compared on the isolated sinus venosus preparation of the toad, bufo marinus. 2. the effects of applied acetylcholine and of low-frequency, or short bursts of high-frequency vagal stimulation were abolished by hyoscine. 3. when intracellular recordings were made from muscle cells of the sinus venosus, it was found that applied acetylcholine caused bradycardia and a cessation of the heart beat which was associated with membrane hy ... | 1989 | 2517987 |
| galanin-like immunoreactivity in sympathetic and parasympathetic neurons of the toad bufo marinus. | immunoreactivity (ir) to galanin (gal) was detected in a wide range of peripheral autonomic neurons in the toad bufo marinus. forty percent of adrenergic nerve cell bodies in paravertebral sympathetic ganglia had gal-ir in addition to neuropeptide y (npy)-ir. some of these neurons projected to systemic arteries. gal-ir was localized in parasympathetic neurons supplying the heart, lung, pulmonary artery, bladder, rectum and tongue. eighty-two percent of intracardiac vagal nerve cell bodies had bo ... | 1989 | 2478927 |
| an eyecup slice preparation for intracellular recording in vertebrate retinas. | this report describes a new preparation for intracellular recording from the vertebrate retina, the eyecup slice preparation. it consists of a small (2 x 5 mm) strip cut from the posterior wall of the eye and thereby keeps the sclera, pigment epithelium and neural retina in place. initial results are presented here for two vertebrates: the turtle, pseudemys scripta elegans, and the toad, bufo marinus. with conventional microscopy, the histological layers of the retina can be resolved, as well as ... | 1989 | 2755176 |
| cardiovascular responses to denervation of pulmocutaneous baroreceptors in toads. | toad pulmocutaneous arterial baroreceptors are connected to afferent fibers carried in the recurrent laryngeal nerves (rlns). bilateral rln denervation in conscious toads (bufo marinus) caused 34 and 78% increases in heart rate (fh) and systemic arterial blood pressure (pa) within 10-15 min, respectively. the variance of pa was significantly increased 2 days after denervation, but pa and fh were not. in additional chronic experiments, 5 of 17 baroreceptor-denervated toads died within the 2-wk re ... | 1989 | 2495740 |
| phospholipid changes during adaptation to acidosis in urinary bladder of bufo marinus. | the purpose of this study was to determine whether phospholipids (pl) play a role in the adaptation to metabolic acidosis by toad urinary bladder epithelium. toads were placed in an nh4cl acidosis for 48 hr. quarter bladders were removed and incubated with [32p]orthophosphate or [3h]arachidonic acid for 1 hr at 25 degrees c. pl were detected by thin layer chromatography, autoradiography, and quantitated by liquid scintillation counting or fractional amounts were determined from phosphate content ... | 1989 | 2494669 |
| innervation of the gastrointestinal canal of the toad bufo marinus by neurons containing 5-hydroxytryptamine-like immunoreactivity. | the gut of the toad, bufo marinus, was examined for evidence of enteric neurons containing 5-hydroxytryptamine-like immunoreactivity. such neurons were absent from the stomach. they were present in the small intestine, with processes confined to the myenteric plexus. immunoreactive nerve cell bodies lay on branches of the pelvic nerves supplying the large intestine; fibres were found in the submucosa of the posterior large intestine and in the muscularis external of the anterior large intestine. ... | 1989 | 2495855 |
| the development of topographical maps and fibre types in toad (bufo marinus) glutaeus muscle during synapse elimination. | 1. the toad glutaeus muscle consists of two muscle compartments. a study has been made of the topographical distribution of motor units in these compartments, in relation to the fibre types which arise during different stages of development. 2. monoclonal antibodies to myosin allowed the distribution of fibre types to be determined. in mature muscles (from toads of greater than 30 g body weight) clusters of type 5 (tonic) fibres were found exclusively at the dorsal surface of the muscle, surroun ... | 1989 | 2511295 |
| extracellular ca2+ controls outward rectification by apical cation channels in toad urinary bladder: patch-clamp and whole-bladder studies. | outward rectifying, cation channels were observed in the epithelial cells of the urinary bladder of the toad. bufo marinus. as studied in isolated cells using the patch-clamp technique, the channel has an average conductance of 24 and 157 ps for pipette potentials between 0 and +60 mv and -60 to -100 mv, respectively, when the major cation in both bath and pipette solutions is k+. the conductance of the channel decreases with increasing dehydration energy of the permeant monovalent cation in the ... | 1989 | 2469799 |
| characteristics of toad bladder urinary acidification. | 1. the urinary acification system present in the bladder of the toad bufo marinus ictericus was investigated by means of an improved technique of mounting the membrane that minimizes the edge damage when the bladder is placed as a sheet between lucite half chambers. 2. in ouabain-treated bladders in the absence of exogenous co2, acidification rates were similar to those observed for turtle bladder. 3. the presence of 1% co2 at the serosal gas phase increased proton secretion (jh). stimulation of ... | 1989 | 2561461 |
| synthesis and characterization of a long-acting fluorescent analog of vasotocin. | this study reports the synthesis of l-desamino-7-lysine- (fluorescein)-8-arginine-vasotocin (7-lys(flu) davt), and describes its biological activity in the isolated urinary bladder of the toad bufo marinus. 7-lys(flu)davt was fully active in increasing bladder permeability to water. a half-maximal hydroosmotic response was obtained at a concentration of 3 x 10(-8) m. a unique feature of this analog was that its response was not readily reversed after removal of the analog from the serosal bathin ... | 1989 | 2508970 |
| the development and the topographic organization of the retinal ganglion cell layer in bufo marinus. | the number and distribution of neurons in the retinal ganglion cell layer were studied from the metamorphic climax to adulthood in the toad bufo marinus. retinal wholemounts stained with cresyl violet showed that total neuron numbers increased from 55,000 at metamorphic climax to about 950,000 in adult animals. during the same time the entire retinal area increased 46-fold from an average 3.4 mm2 to 157 mm2. the morphological character of the neurons and their density across the retina changed d ... | 1989 | 2498114 |
| stimulation by aldosterone of a conductive chloride pathway in toad skin. | as a rule, chloride movement (jc1-) across amphibian skin is considered to be passive; this is implied in fact for preparations incubated in ringer's fluid, since short-circuit current (isc) is the quantitative expression of net, active sodium transport (jna+). the nature of the cl- pathway(s) was investigated by incubating amphibian skin (mostly bufo marinus) with cl- present on the epithelial side only, and after blocking jna+ by combined treatment with ouabain and amiloride. in such condition ... | 1989 | 2478240 |
| interphotoreceptor retinoid-binding protein promotes rhodopsin regeneration in toad photoreceptors. | interphotoreceptor retinoid-binding protein (irbp) has been hypothesized to function as an intercellular shuttle in the vertebrate eye, serving to transport retinoids between the retinal pigment epithelium (rpe) and photoreceptors in the process by which visual pigment is regenerated after photolysis. this hypothesis was tested in preparations utilizing the toad (bufo marinus) eye and purified, initially ligand-free irbp obtained from the bovine eye. rod outer segments (ros) or neural retinas we ... | 1990 | 2118660 |
| the changing distribution of neurons in the inner nuclear layer from metamorphosis to adult: a morphometric analysis of the anuran retina. | the generation and changing distribution of neurons of the inner nuclear layer (inl) in the retina of two anuran species, bufo marinus and xenopus laevis, were studied from metamorphosis to adult. morphometric studies were undertaken at six developmental stages in bufo and four in xenopus. the number and thickness of neurons in the inl were established in 29 predetermined retinal locations from serial sections of the eyes cut vertically or horizontally. the total number of neurons in the inl inc ... | 1990 | 2118741 |
| a fluorescent analogue of hydrin 1: a new probe for vasotocin receptors. | hydrin 1 is the biosynthetic precursor of vasotocin in xenopus laevis. we have synthesized deamino and fluorescein analogues of hydrin 1 and characterized their physiological action in the urinary bladder of the toad, bufo marinus. 1-deamino-hydrin 1 (d-hydrin) was more potent than vasotocin in stimulating osmotic water flow across intact bladders and more potent than vasotocin in displacing tritium-labeled vasopressin [( 3h]avp) from cell membranes. 1-deamino-[11-lysine (fluorescein)]-hydrin 1 ... | 1990 | 2121046 |
| salmonellas from the cane toad, bufo marinus. | 1990 | 2121128 | |
| determination of intracellular ph and pco2 after metabolic inhibition by fluoride and nitrilotriacetic acid. | mean intracellular ph (phi) and pco2 (pico2) have been analysed based on ph and total co2 measurements in tissue homogenates. tissues were sampled from undisturbed worms (sipunculus nudus), squid (illex illecebrosus), trout (salmo gairdneri), toads (bufo marinus), and rats. homogenate metabolism was inhibited by the addition of potassium fluoride and nitrilotriacetic acid (nta). model calculations revealed that the influence of dilution, medium buffers, and contamination by extracellular fluids ... | 1990 | 2124717 |
| detergent-based isolation of marginal bands of microtubules from nucleated erythrocytes. | we have developed a new, detergent-based method for the isolation of marginal bands (mbs) of microtubules from non-mammalian vertebrate erythrocytes. the critical step in mb isolation is selective removal of the "membrane skeleton" network (ms), within which the mb is enclosed. to test potential ms solubilizing agents systematically, we prepared dogfish (mustelus canis) erythrocyte cytoskeletons in the presence of protease inhibitors and stored them at -20 degrees c in medium containing 50% glyc ... | 1990 | 2127917 |
| detection of n-acetylated forms of beta-endorphin and nonacetylated alpha-msh in the intermediate pituitary of the toad, bufo marinus. | steady-state analysis of the acid extracts of the intermediate pituitary of the toad, bufo marinus, revealed the presence of multiple forms of beta-endorphin and alpha-msh. approximately 98% of the immunoreactive beta-endorphin was n-acetylated. the major form of n-acetylated beta-endorphin, which represented 81.5% of the total beta-endorphin recovered from this tissue, had an apparent molecular weight of 1.2 kda and a net charge of +1 at ph 2.75. approximately 98% of the immunoreactive alpha-ms ... | 1990 | 2172945 |
| morphological classification and retinal distribution of large ganglion cells in the retina of bufo marinus. | the retrograde transport of horseradish peroxidase (hrp) and cobaltic-lysine complex (clc) was used to morphologically characterize large ganglion cells (gcs) and to determine their distribution in retinal wholemounts and in sectioned material in the retina of bufo marinus. large gcs, amounting to about 0.5% of total gc population, were defined to be those with very large dendritic field sizes varying between 0.1 mm2 to 0.6 mm2 and cell soma sizes of between 100 microns 2 to 400 microns 2. these ... | 1990 | 2108873 |
| response properties of the toad retinal pigment epithelium. | electrophysiologic responses were recorded in vitro from the retina of the toad, bufo marinus. in the isolated retinal pigment epithelium (rpe)-choroid preparation, a decrease in the k+ concentration outside the apical membrane evoked a sequence of trans-epithelial (tep) and membrane potential changes. a hyperpolarization originating at the rpe apical membrane that increased the tep was followed by a delayed hyperpolarization originating at the basal membrane that decreased the tep. this respons ... | 1990 | 2173687 |
| compensation of progressive hypercapnia in the toad (bufo marinus) and the bullfrog (rana catesbeiana). | toads (bufo marinus l.) and bullfrogs (rana catesbeiana shaw) were subjected to a series of 24 h step increases in aerial co2 (2, 4, 6 and 8%) to assess the degree of extracellular ph compensation at each co2 level and to ascertain the importance of cutaneous ion transport in this process. elevation of plasma [hco3-] occurs during the 24 h period, with the bullfrogs showing a greater ability to compensate at each step. there was no indication that a [hco3-] threshold of 30 mmol l-1 existed in ei ... | 1990 | 2106565 |
| neurotensin is localized to paracrine cells in the urinary bladder of the turtle, chrysemys picta. | urinary bladder from the painted turtle, chrysemys picta, contains a substantial population of endocrine/paracrine cells scattered through the mucosal epithelium which immunostains using antisera directed toward mammalian neurotensin (nt). radiommunoassay of 0.1 n hcl extracts of chrysemys bladder indicated an immunoreactive nt (int) concentration of 161 +/- 39 pmol/g tissue (n = 9), an amount lower but comparable in magnitude to that found in mucosal scrapings of the intestine (926 +/- 125 pmol ... | 1990 | 2202609 |
| co-localization of calcitonin gene-related peptide- and substance p-like immunoreactivity in mucosal intra-epithelial nerves in the toad colon. | mucosal intra-epithelial nerve terminals have been found in the colon of the toad, bufo marinus. co-localized in the fibres are calcitonin gene-related peptide (cgrp)-like immunoreactivity (li) and substance p (sp)-li. the intraepithelial nerves are likely to be terminals of primary afferent sensory neurones. fibres with vasoactive intestinal peptide (vip)-li or neuropeptide y (npy)-li also supply the mucosa but do not penetrate the epithelium. | 1990 | 1701868 |
| effects of acetylcholine and substance p on electrical activity of intact toad gastric muscles. | by using isolated gastric muscle cells of bufo marinus, others have studied the mechanism of action of muscarinic agonists and substance p (sp). to compare responses of isolated cells with those of intact muscles, we have studied the effects of acetylcholine (ach) and sp on membrane potentials of circular muscle cells in strips of intact muscle from the toad gastric corpus region. these cells had average resting potentials of -69 +/- 0.7 mv. membrane potential rhythmically depolarized, producing ... | 1990 | 1689118 |
| dual regulation of m current in gastric smooth muscle cells: beta-adrenergic-muscarinic antagonism. | the effects of the beta-adrenergic agent isoproterenol on membrane currents were studied in freshly dissociated gastric smooth muscle cells of bufo marinus. voltage-clamp experiments were carried out with patch pipettes in the tight-seal, whole-cell recording mode or with conventional microelectrodes. isoproterenol induced a current identified as m current by the following criteria: the induced current is outward and carried by k+ ions, is suppressed by muscarine or acetylcholine, remains steadi ... | 1990 | 2177185 |
| lateral diffusion of visual pigments in toad (bufo marinus) rods and in catfish (ictalurus punctatus) cones. | 1. the lateral diffusion coefficient, d, was determined for visual pigments in red rods, green rods and red-sensitive cones with a photon-counting microspectrophotometer. 2. a novel protocol that involved the placement on a photoreceptor of a single micromeasuring/bleaching beam permitted the determination of d of the pigment. 3. demonstration that d for red rods compared very well with values obtained by other workers using other means validated the protocol. 4. applied to green rods, the proto ... | 1990 | 2128335 |
| amiloride inhibits the vasopressin-induced increase in epithelial water permeability. | the vasopressin (vp)-induced increase in water permeability in high-resistance, amphibian epithelia is not altered by the abolition of net na+ flux caused by amiloride added to the apical bathing medium. in this work we looked at the effects on water transport of amiloride added to the serosal medium at a concentration (10(-3) m) known to inhibit na+/h+ exchange. in urinary bladders of bufo marinus, amiloride partially blocked the hydrosmotic response to vp. a similar inhibition was found with c ... | 1990 | 1964723 |
| sympathetic nerve stimulation and applied transmitters on the sinus venosus of the toad. | 1. the effect of sympathetic nerve stimulation on pacemaker cells of the isolated sinus venosus of the toad, bufo marinus, were examined using intracellular recording techniques. 2. train of stimuli applied to the sympathetic outflow led to a two-component increase in heart rate. shortly after the onset of stimulation the rate of discharge of pacemaker action potentials increased. after the end of the train of stimuli, the heart rate fell and then again increased to remain high for several minut ... | 1990 | 2126042 |
| morphology and distribution of serotonin-like immunoreactive amacrine cells in the retina of bufo marinus. | using an antibody against serotonin (5-hydroxytryptamine, 5-ht), serotonin-like immunoreactive (serotonin-ir) neurons were demonstrated in the retina of adult bufo marinus. all immunoreactive neurons were identified as amacrine cells (acs). the dendrites of serotonin-ir acs branched diffusely and densely throughout all levels of the inner plexiform layer (ipl) of the retina. the great majority of these cell somata were located in the vitread part of the inner nuclear layer (inl) and a few of the ... | 1990 | 2124921 |
| slowing of velocity during isotonic shortening in single isolated smooth muscle cells. evidence for an internal load. | in single smooth muscle cells, shortening velocity slows continuously during the course of an isotonic (fixed force) contraction (warshaw, d.m. 1987. j. gen. physiol. 89:771-789). to distinguish among several possible explanations for this slowing, single smooth muscle cells were isolated from the gastric muscularis of the toad (bufo marinus) and attached to an ultrasensitive force transducer and a length displacement device. cells were stimulated electrically and produced maximum stress of 144 ... | 1990 | 2121895 |
| evidence for na+/h+ exchange in vertebrate rod photoreceptors. | in this paper, we have documented our investigation of ph regulation in the rod photoreceptor of the toad, bufo marinus. unlike other neural tissues, the retina depends upon aerobic glycolysis to meet its energy requirements. a consequence of its reliance on glycolysis is a large metabolic production of protons (h+) which must be extruded by ph regulating mechanisms. based on the work of previous authors, we propose that rods share these same characteristics with whole retina. our results in rod ... | 1990 | 2167233 |
| kinetics of local anesthetic inhibition of neuronal sodium currents. ph and hydrophobicity dependence. | this study assesses the importance of local anesthetic charge and hydrophobicity in determining the rates of binding to and dissociation from neuronal na channels. five amide-linked local anesthetics, paired either by similar pka or hydrophobicity, were chosen for study: lidocaine, two tertiary amine lidocaine homologs, a neutral lidocaine homolog, and bupivacaine. voltage-clamped nodes of ranvier from the sciatic nerve of bufo marinus were exposed to anesthetic externally, and use-dependent ("p ... | 1990 | 2166602 |
| kinetic analysis of phasic inhibition of neuronal sodium currents by lidocaine and bupivacaine. | phasic ("use-dependent") inhibition of sodium currents by the tertiary amine local anesthetics, lidocaine and bupivacaine, was observed in voltage-clamped node of ranvier of the toad, bufo marinus. local anesthetics were assumed to inhibit sodium channels through occupation of a binding site with 1:1 stoichiometry. a three-parameter empirical model for state-dependent anesthetic binding to the na channel is presented: this model includes two discrete parameters that represent the time integrals ... | 1990 | 2166601 |
| light-induced calcium release and re-uptake in toad rods. | laser micromass analysis was used to investigate the effect of light on the ca content of rod outer segments in the isolated retina and eyecup of the toad, bufo marinus. isolated retinas were incubated in ringer for which most of the ca (normally 97% 40ca) was replaced with 44ca, so that release of internal ca (as 40ca) could be distinguished from the uptake of 44ca from the external medium. continuous illumination produced a decline in outer segment 40ca content. in bright light, the decrease i ... | 1990 | 2115909 |
| effects of vagal stimulation and applied acetylcholine on the arrested sinus venosus of the toad. | 1. the effects of vagal stimulation and applied acetylcholine were compared on sinus venosus preparations of the toad, bufo marinus, in which beating had been inhibited by adding the organic calcium antagonist nifedipine. 2. bath-applied acetylcholine and vagal stimulation each caused membrane hyperpolarizations which were abolished by hyoscine. 3. whereas the hyperpolarization that accompanied vagal stimulation was largely unaffected by barium ions, that produced by bath-applied acetylcholine w ... | 1990 | 2120424 |
| evolutionary specificity of hydrins, new hydroosmotic neuropeptides: occurrence of hydrin 2 (vasotocinyl-gly) in the toad bufo marinus but not in the viper vipera aspis. | hydrin 2 (vasotocinyl-gly), a hydroosmotic peptide resulting from differential processing of provasotocin and recently identified in frog neurohypophysis, has been looked for in the pituitary gland of an exotic toad (bufo marinus) and of a reptile (vipera aspis). hydrin 2 has been found in the amphibian but not in the reptile. this result confirms the evolutionary specificity of hydrin 2 that has been identified only in frogs and toads but not in birds and reptiles. occurrence of hydrin 2 is exp ... | 1990 | 2110910 |
| prostaglandins as mediators of acidification in the urinary bladder of bufo marinus. | experiments were performed to determine whether prostaglandins (pg) play a role in h+ and nh4+ excretion in the urinary bladder of bufo marinus. ten paired hemibladders from normal toads were mounted in chambers. one was control and the other hemibladder received pge2 in the serosal medium (10(-5) m). h+ excretion was measured by change in ph in the mucosal fluid and reported in units of nmol (100 mg tissue)-1 (min)-1. nh4+ excretion was measured colorimetrically and reported in the same units. ... | 1990 | 2158109 |
| recovery from bleaching in photoreceptors promoted by biotin, pyruvate, and glucose. | in the rods of bufo marinus and other species, bleaching of the rhodopsin in isolated cells leads to a loss of sensitivity and response amplitude and to a shortened response duration. these changes are permanent for cells bathed in ringer's solution. they are due to as yet unknown modulations in the transduction biochemistry. in this paper, we report that these changes can be partly or completely reversed by supplying biotin, pyruvate, and elevated glucose to the rod. the time course of this rev ... | 1990 | 2125464 |
| weber and noise adaptation in the retina of the toad bufo marinus. | responses to flashes and steps of light were recorded intracellularly from rods and horizontal cells, and extracellularly from ganglion cells, in toad eyecups which were either dark adapted or exposed to various levels of background light. the average background intensities needed to depress the dark-adapted flash sensitivity by half in the three cell types, determined under identical conditions, were 0.9 rh*s-1 (rods), 0.8 rh*s-1 (horizontal cells), and 0.17 rh*s-1 (ganglion cells), where rh* d ... | 1990 | 2110969 |
| signal transmission through the dark-adapted retina of the toad (bufo marinus). gain, convergence, and signal/noise. | responses to light were recorded from rods, horizontal cells, and ganglion cells in dark-adapted toad eyecups. sensitivity was defined as response amplitude per isomerization per rod for dim flashes covering the excitatory receptive field centers. both sensitivity and spatial summation were found to increase by one order of magnitude between rods and horizontal cells, and by two orders of magnitude between rods and ganglion cells. recordings from two hyperpolarizing bipolar cells showed a 20 tim ... | 1990 | 2110968 |
| mechanical transients of single toad stomach smooth muscle cells. effects of lowering temperature and extracellular calcium. | smooth muscle's slow, economical contractions may relate to the kinetics of the crossbridge cycle. we characterized the crossbridge cycle in smooth muscle by studying tension recovery in response to a small, rapid length change (i.e., tension transients) in single smooth muscle cells from the toad stomach (bufo marinus). to confirm that these tension transients reflect crossbridge kinetics, we examined the effect of lowering cell temperature on the tension transient time course. once this was co ... | 1990 | 2110967 |
| effect of hematocrit on behavioral thermoregulation of the toad bufo marinus. | this study tested the hypothesis that the oxygen capacity of blood, indexed by hematocrit, affects the body temperature (tb) selected by toads (bufo marinus) in a thermal gradient. anesthetized toads (brevital sodium; 40 mg/kg im) were fitted with a cloacal thermistor and femoral artery cannula. after recovery, they were placed in a thermal gradient ranging from approximately 10 to 40 degrees c. tb was measured for 24 h. then 1-2 ml blood were withdrawn and replaced with an equal volume of eithe ... | 1990 | 2109945 |
| effect of temperature on cardiac vagal action in the toad bufo marinus. | the effect of temperature on the action of the vagus nerve on the heart was studied in the toad bufo marinus. experiments were performed on two groups of toads, in one the heart was perfused at a constant rate with oxygenated ringer's solution and in the other the circulation was left intact. in all toads there was a linear relationship between pulse interval (pi) and the frequency of vagal stimulation (fv) at any one temperature. the slope of this relationship changed with temperature, the effe ... | 1990 | 2109033 |
| k(+)-evoked müller cell depolarization generates b-wave of electroretinogram in toad retina. | we tested the hypothesis that a light-evoked increase in [k+]o produces a depolarization of the müller cell membrane, which in turn generates the electroretinogram b-wave current. using bufo marinus isolated retinas and k(+)-selective microelectrodes, we recorded two distinct light-evoked increases in extracellular k+ concentration: one in the inner plexiform layer and the other near the outer plexiform layer; the "distal" k+ increase was found over only 10-microns depth and had a maximum amplit ... | 1990 | 2107544 |
| compartmental and topographical specificity of reinnervation of the glutaeus muscle in the adult toad (bufo marinus). | the extent to which the compartmental and topographical innervation patterns were re-established in the mature glutaeus muscle after nerve cut was determined by hrp retrograde labelling procedures and single motor unit glycogen depletion experiments. glutaeus muscle axons normally cluster together along the length of the sciatic nerve and enter the triceps femoris nerve along with axons to the cruralis and tensor fasciae latae muscles. glutaeus axons did not specifically reinnervate the glutaeus ... | 1990 | 2111337 |
| the effects of aldehydes on the inward rectifier of skeletal muscle fibres from the toad bufo marinus. | a comparative study of the effects of formaldehyde and glutaraldehyde on the inward rectification in skeletal muscle fibre of the toad bufo marinus was made using two different techniques. in whole sartorius muscle fibres formaldehyde produced a transient increase in conductance, followed by a decrease while glutaraldehyde only produced the second effect, with a rather fast time course. in cut end single fibres both aldehydes produced only a reduction of conductance and eventually the abolition ... | 1990 | 2152375 |
| hyperbaric oxygen effect on active na+ transport across isolated toad skin. | the effect of hyperbaric oxygen (hbo) on na+ transport across the isolated toad (bufo marinus) skin was studied by measuring the transepithelial short-circuit current (isc) and resistance (r) at 5, 8, and 10 ata po2 and 15 ata normoxia during steady state conditions. the imposition of 5, 8, and 10 ata po2 for 2 h resulted in 45, 52, and 85% decrease in isc, respectively. this decrease in isc was always accompanied by an increase in r. when amiloride (10(-4) m) was added to the bathing medium, is ... | 1990 | 2107615 |
| dendritic morphology and retinal distribution of tyrosine hydroxylase-like immunoreactive amacrine cells in bufo marinus. | tyrosine hydroxylase-like immunoreactive (th-ir) amacrine cells (acs) in the retina of metamorphosing and adult bufo marinus were visualized, and their retinal distribution established, using immunohistochemistry on retinal wholemount and sectioned material. the somata of th-ir acs were located in the innermost part of the inner nuclear layer (inl). their dendrites branched predominantly in the scleral sublamina of the inner plexiform layer (ipl), with sparse branching also in the vitreal sublam ... | 1990 | 1971740 |
| prostaglandin regulation of h+ secretion in amphibian epithelia. | the role of prostaglandins in regulating h+ excretion in amphibian epithelia was investigated. the abdominal skin of the southern leopard frog rana pipiens and the urinary bladder of the toad bufo marinus were used to measure proton excretion across their mucosal surface. prostaglandin f2 alpha (pgf2 alpha) produced a dose-dependent inhibition of h+ excretion across the frog skin. frogs pretreated with ibuprofen (30 mg.kg-1.day-1 for 3 days) showed an enhanced proton excretion similar to that ob ... | 1991 | 1903604 |
| amiloride blockage of na+ channels in amphibian epithelia does not require external ca2+. | noise analysis was used to study the influence of external ca2+ on the blockage of na+ transport by amiloride. experiments were done using frog skin (rana temporaria and rana catesbeiana), toad urinary bladder (bufo marinus) and epithelia of a6 cells. in nondepolarized skins and bladders, removal of ca2+ from the mucosal bath diminished markedly the inhibitory effect of amiloride. ca2+ depletion also gave rise to the appearance of an additional noise component related to cation movement through ... | 1991 | 1664939 |
| blockage of na+ currents through poorly selective cation channels in the apical membrane of frog skin and toad urinary bladder. | the blockage of na+ movements through the poorly selective cation channels in the apical membrane of frog skin (rana temporaria) and toad urinary bladder (bufo marinus) was investigated with noise, impedance analysis and microelectrode techniques. na+ currents through this pathway were studied with nacl ringer solutions on both sides. after removal of ca2+ and other divalent cations from the mucosal compartment, a considerable part of isc became insensitive to amiloride. in frog skin, the inhibi ... | 1991 | 1649987 |
| polymorphism in purified guanylate cyclase from vertebrate rod photoreceptors. | guanylate cyclase from rod photoreceptors of amphibian (toad, bufo marinus, and frog, rana catesbeiana) and bovine retinas was solubilized and purified by a single chromatography step on a gtp-agarose column. silver staining of purified amphibian enzymes in sds/polyacrylamide gels disclosed a doublet band (110 and 115 kda), while the bovine enzyme appeared as a singlet band (110 kda). the identification of these guanylate cyclases was confirmed using three chromatography systems with the purifie ... | 1991 | 1675787 |
| leptospires isolated from toads and frogs on the island of barbados. | four pathogenic strains of leptospires were isolated from the kidneys of toads (bufo marinus) and seven from frogs (eleutherodactylus johnstonei). isolates from two toads and one frog belonged to serovar bim, the causative agent of most cases of severe leptospirosis on barbados. the other eight strains belonged to a new serovar within the australis serogroup. the name bajan is proposed for this new serovar of leptospira interrogans. | 1991 | 1741925 |
| functional properties of interphotoreceptor retinoid-binding protein. | it has been hypothesized that interphotoreceptor retinoid-binding protein (irbp) functions as a two-way carrier of retinoid between the retinal pigment epithelium (rpe) and rod photoreceptors in the vertebrate eye. this hypothesis has been tested in recent studies that have employed purified, initially ligand-free, bovine irbp and the "rpe-eyecup" obtained from the toad (bufo marinus) eye. the present experiments further characterize the irbp/rpe-eyecup system with respect to (i) the solubilizat ... | 1991 | 1775528 |
| m-wave of the toad electroretinogram. | 1. in the retina, two distinct, light-evoked releases of k+ have been described. one takes place in the outer plexiform layer (opl) and is termed the "distal k+ increase." the other takes place in the inner plexiform layer (ipl) and is termed the "proximal k+ increase." although the distal k+ increase generates the electroretinogram (erg) b-wave, the contribution of the much larger proximal k+ increase to the erg is less well understood. in this paper we detail our investigation of the proximal ... | 1991 | 1812226 |
| a method for the demonstration of nadph-diaphorase activity in anuran species using unfixed retinal wholemounts. | the presence of nadph-diaphorase enzyme has been previously revealed in fixed mammalian retinal tissue (sagar, 1986). fixed retinae of bufo marinus and xenopus laevis failed to yield selective staining when reacted for nadph-diaphorase. satisfactory staining of retinal neurons was attained when the histochemical reaction was carried out in unfixed retinal wholemounts. the applied method included the following steps: 1) dissection of the fresh retina and the separation of the neural retina from a ... | 1991 | 1908262 |
| a possible iridovirus in erythrocytes of bufo marinus in costa rica. | icosahedral viral particles were found in the cytoplasm of erythrocytes and splenic reticular cells of a marine toad (bufo marinus) collected from costa rica. capsids had a maximum diameter of 312 nm and a spherical core with biphasic electron density. viruses in erythrocytes were associated with cytoplasmic assembly areas and vacuoles in cytoplasm. nuclei had finely granular material of decreased electron density located centrally, but contained no viral particles. a group of unenveloped viral ... | 1991 | 1920667 |
| an epidemiological study of snake bite envenomation in papua new guinea. | we report a study of 347 patients with snake bite envenomation in papua new guinea. the male: female ratio of the victims was 1.6:1 and their mean age was 24.5 years; 26% were children less than 15 years old. in all cases in which the bite site was known (334) the snake had bitten the extremities of the victim, with 71.3% of these bites being on the ankle or below. the patients came from three regions: urban papua, rural papua and (mostly rural) new guinea. snake bites occurred more frequently d ... | 1991 | 1994203 |
| probabilistic secretion of quanta from the release sites of nerve terminals in amphibian muscle modulated by seasonal changes. | the number of quanta secreted from release sites along visualized terminal branches at toad (bufo marinus) neuromuscular junctions during different seasons was determined. terminal branches were visualized by prior staining with the fluorescent dye, 3,3'-diethyloxadicarbocyanine iodide (dioc2(5)). the average number of quanta secreted by release sites and recorded with an extracellular electrode was determined at different positions along terminal branches in winter and summer. there was a decre ... | 1991 | 1687704 |
| transport-related modulation of the membrane properties of toad urinary bladder epithelium. | impedance analysis and transepithelial electrical measurements were used to assess the effects of the apical membrane na+ channel blocker amiloride and anion replacement on the apical and basolateral membrane conductances and areas of the toad urinary bladder (bufo marinus). mucosal amiloride addition decreased both apical and basolateral membrane conductances (ga and gbl, respectively) with no change in membrane capacitances (ca and cbl). consequently, the specific conductances of these membran ... | 1991 | 1661156 |
| intracellular ph in the toad bufo marinus following hypercapnia. | we investigated the effects of hypercapnia on intracellular acid-base regulation in brain and liver of the toad bufo marinus l. after 1 h at 5% co2, arterial pco2 increased significantly, from 1.6 +/- 0.04 to 5.7 +/- 0.23 kpa, while brain and liver intracellular ph (phi) decreased significantly. reductions in phi of both tissues were partially compensated by increased levels of bicarbonate. surprisingly, however, compensation was lower than expected in brain and higher than expected in liver. we ... | 1991 | 1757774 |
| effects of putative modulators of relaxation microinjected into intact amphibian smooth muscle cells. | 1. single smooth muscle cells were isolated intact from the stomach of the toad bufo marinus. the relaxation of cells following cessation of electrical stimulation was compared with those relaxed by pressure microinjection of either metal ion chelators or cyclic nucleotides. 2. injection of either a ca2+ chelator or 3',5'-cyclic amp slowed or halted shortening and promoted re-extension of a cell or collapse of membrane evaginations (blebs) in a manner similar to that following cessation of elect ... | 1991 | 1665860 |
| tyrosine hydroxylase-immunoreactive elements in the distal retina of bufo marinus: a light and electron microscopic study. | tyrosine hydroxylase-immunoreactive elements in the distal retina of bufo marinus were investigated using light and electron microscopic immunocytochemistry. at the light microscopic level, immunoreactive somas were seen in the proximal part of the inner nuclear layer, and immunoreactive processes projected both to the inner and outer plexiform layers. in some instances stained axon-like processes traveled from the inner plexiform layer, across the inner nuclear layer to the distal retina. immun ... | 1991 | 1686574 |
| physiological significance of behavioral hypothermia in hypoxic toads (bufo marinus). | we tested the hypotheses that hypoxic toads (bufo marinus) in a thermal gradient would select a lower than normal temperature and that this behavioral response would be beneficial. under normoxic conditions, selected body temperature was 24.2 +/- 3.6 degrees c. when inspired o2 was 10% or less, mean selected temperature decreased to 15.3 +/- 2.4 degrees c. the theoretical advantages of hypoxia-induced hypothermia we tested include (1) a reduction of oxygen uptake (vo2) by a q10 effect; (2) incre ... | 1991 | 1940767 |
| retinal distribution of ganglion cells which project to the ipsilateral optic tectum in bufo marinus. | the retinotectal projection in anura is mainly crossed, although a small proportion of optic axons projects to the ipsilateral tectum. using the fluorescent carbocyanide dye, dii, we mapped the retinal topography of ganglion cells which project to the ipsilateral tectum in adult bufo marinus. dii was injected into particular locations in the right tectum. after 10 days survival both the right and the left retinals were wholemounted and the number and retinal position of retrogradely filled gangl ... | 1991 | 1933341 |
| potassium-evoked responses from the retinal pigment epithelium of the toad bufo marinus. | changes in the apical and basal membrane potentials and the resultant changes in the transepithelial potential were recorded from the isolated retinal pigment epithelium of the toad bufo marinus while the potassium concentration superfusing the apical membrane was changed. lowering apical potassium caused an initial apically-generated hyperpolarization that increased the transepithelial potential which was usually followed by a delayed basally-generated hyperpolarization that decreased the trans ... | 1991 | 1915678 |
| clinostomum attenuatum (digenea) from the eye of bufo marinus. | two specimens of the cane toad, bufo marinus, were found with single worm infestations of the eye. one worm was excysted in the eye chamber, the other still encysted in the choroid layer; both worms were identified as clinostomum attenuatum. this finding is both a new host record and a new site of development for this amphibian parasite. | 1991 | 1907655 |
| acid-base regulation in the toad bufo marinus during environmental hypoxia. | gas exchange and the correlated changes in blood and tissue metabolic and acid-base status were investigated during long term exposure of the toad bufo marinus to graded levels of hypoxia. during hypoxia, pco2 values in blood and tissues fell, leading to a transient alkalosis in the extracellular but not in the intracellular space. a reduction in blood perfusion of the skin during hypoxia may explain why pco2 was low in sartorius muscle under normoxia, but approached the pco2 values found in oth ... | 1991 | 1658901 |
| position- and fibre type-dependent selectivity by regenerating motor axons in reformation of the topographical projection to the glutaeus muscle in the adult toad (bufo marinus). | the toad glutaeus magnus muscle receives a topographical innervation dependent on the rostrocaudal origins of glutaeus motor axons on the spinal cord. the same projection is re-established in adult animals after cutting the glutaeus muscle nerve and allowing regenerating axons to reinnervate the muscle (brown and everett (1990) j. comp. neurol. 292:363-372). to determine whether the topographically selective reinnervation of the glutaeus muscle comes about because of genuine positional qualities ... | 1991 | 1655833 |
| behavioral thermoregulation of the toad, bufo marinus: effects of air humidity. | two experiments were performed. the first tested the hypothesis that the toad, bufo marinus, will select a lower ambient temperature under dry environmental conditions. this behavioral response would reduce evaporative water loss and facilitate survival on land. the second experiment measured the effects of temperature on evaporative water loss. in the first experiment, toads were placed in a thermal gradient (11-40 degrees c) for 3 days. on days 1 and 3, water-filled dishes were placed along th ... | 1991 | 1909745 |
| prolonged depolarization in rods in situ. | intracellular recordings were made from rods in the superfused retina of the marine toad (bufo marinus). it was found that injection of a brief depolarizing current pulse (0.04-1 na) evoked a distinctive, long-lasting response, here called "the prolonged depolarization." the response appears to be regenerative, has a stereotypical waveform, is typically about 6 mv in amplitude and 3 s in duration, and has a relatively long recovery period (10-60 s). as a rule, the response cannot be directly evo ... | 1991 | 1909172 |
| nadph-diaphorase positive neurons in the retina of bufo marinus: selective staining of bipolar and amacrine cells. | unfixed retinal tissues of adult bufo marinus were reacted for nadph-diaphorase histochemistry that resulted in selective staining of populations of bipolar and amacrine cells. the number of stained bipolar cells in the retina was estimated to be 233,600 +/- 38,900 (mean +/- s.d.). these cells were non-uniformly distributed across the retina with the highest density of 4,308 cells/mm2 along the visual streak decreasing to lowest density of 1,378 cells/mm2 at the dorsal and ventral poles of the r ... | 1991 | 1908263 |
| effect of neuropeptide-y and galanin on autonomic control of heart rate in the toad, bufo marinus. | the effects of neuropeptide-y (npy) and galanin (gal) on the autonomic control of heart rate were investigated in the anaesthetised toad, bufo marinus. both vagosympathetic trunks were sectioned to prevent reflex changes in heart rate, and the cardiac responses to electrical stimulation of either the vagal or sympathetic fibres to the heart assessed. intravenous, bolus doses of 10 or 20 micrograms (2 or 4 nmol) npy and 5 or 10 micrograms (1.5 or 3 nmol) gal caused pronounced pressor responses bu ... | 1991 | 1717535 |
| multiple types of ca2+ channels in visceral smooth muscle cells. | single-channel currents were recorded from two classes of ca2+ channels in visceral smooth muscle cells isolated from the stomach of the toad, bufo marinus: a class of small-conductance channels (approximately 11 ps) and a class of large-conductance channels (approximately 26 ps). small-conductance channels were present in a majority of patches and gave rise to a slowly inactivating current (t1/2 approximately 250 ms at 0 mv). openings of large-conductance channels could be unequivocally resolve ... | 1991 | 1710335 |
| contribution from a ph- and tonicity-sensitive k+ conductance to toad translens short-circuit current. | studies of toad (bufo marinus) lenses mounted in ussing-type chambers revealed that: (1) the translens short-circuit current (isc) across the posterior surface is primarily carried by the movement of na+ from the posterior bathing solution to the lens; (2) across the anterior face the majority of the isc is mediated by ba(2+)-sensitive channels and the remaining current is rapidly reduced by ouabain; (3) most of the anterior k+ conductance is of the tonicity-sensitive, quinidine-inhibitable type ... | 1991 | 1901798 |
| effects of central and peripheral chemoreceptor stimulation on ventilation in the marine toad, bufo marinus. | the contributions of central and peripheral chemoreceptors to respiratory control in lightly anesthetized bufo marinus, were assessed by measuring the ventilatory responses to unidirectional ventilation (udv) of the lungs at several concentrations of co2 or o2, during intracranial perfusion (icp) with hypercapnic acidic (5% co2, ph 7.2) or hypocapnic alkaline (0% co2, ph 8.3) mock csf solutions. peripheral chemoreceptor stimulation alone (hypoxia or hypercapnia during icp with hypocapnic alkalin ... | 1991 | 1906195 |
| effects of environmental conditions on mitochondrial-rich cell density and chloride transport in toad skin. | chloride flux across amphibian skin is usually passive, yet largely conductive; previous reports have suggested that aldosterone influences this pathway. the conductive cl- pathway and its regulation were examined further, across the abdominal skin of toads (bufo marinus) adapted to various environments. short-circuit current (isc), total conductance (gt) and cl- influx (jcl) were measured in conditions such that there was net cl- movement in absence of na+ transport. in salt-deprived animals co ... | 1991 | 1905398 |
| probabilistic secretion of quanta from nerve terminals in toad (bufo marinus) muscle modulated by adenosine. | 1. a study has been made of the effect of blocking endogenous adenosine on the statistics of quantal secretion at nerve terminals in toad (bufo marinus) muscle during summer and winter. 2. exogenous adenosine (10-50 microm) reduces the mean quantal content of the endplate potential (epp) recorded with an intracellular microelectrode (m) by 36 +/- 6% (mean +/- s.e.m.), independent of the control value of m in both summer and winter. the variance of the epp (s2) was reduced by adenosine in proport ... | 1991 | 1841950 |
| hyperpolarization-activated cationic channels in smooth muscle cells are stretch sensitive. | the properties of hyperpolarization-activated channels were studied in single smooth muscle cells from the stomach of the toad, bufo marinus, using the patch-clamp technique. in cell-attached patches, inward channel currents were activated by hyperpolarizing pulses from a holding potential of -20 mv to potentials more negative than -60 mv. the activity of the channels increased and their latency of activation decreased as the hyperpolarization was increased. the slope conductance of the channels ... | 1991 | 1707158 |
| calcium homeostasis in single intact smooth muscle cells. | we have demonstrated that iso produces part of its negative inotropic action through activation of the plasmalemmal na+/k+ pump, and reduction of [na+]i. this action is mediated by the beta-adrenergic receptor through activation of adenylate cyclase. the reduction of [na+]i is most probably translated to a change in the contractile state of the cell through activation of the na+/ca2+ exchanger. while the exchanger is at equilibrium when the cell is at rest, after iso it would extrude ca2+ at the ... | 1991 | 1803898 |
| nitric oxide synthase immunoactivity and nadph diaphorase enzyme activity in neurons of the gastrointestinal tract of the toad, bufo marinus. | the presence of nitric oxide synthase (nos) was demonstrated immunohistochemically, and nadph diaphorase was demonstrated by enzyme histochemistry in neurons throughout the gastrointestinal tract of the anuran amphibian, bufo marinus. successive staining showed that nos immunoreactivity and nadph diaphorase activity occurred in precisely the same subgroup of enteric neurons. subsequent detailed studies of the distribution of these neurons were made using nadph diaphorase histochemistry. numerous ... | 1992 | 1282824 |
| phosphorylation of na,k-atpase alpha-subunits in microsomes and in homogenates of xenopus oocytes resulting from the stimulation of protein kinase a and protein kinase c. | the phosphorylation of the alpha-subunit of na+/k(+)-transporting atpase (na,k-atpase) by camp-dependent protein kinase (pka) and protein kinase c (pkc) was characterized in purified enzyme preparations of bufo marinus kidney and duck salt gland and in microsomes of xenopus oocytes. in addition, we have examined camp and phorbol esters, which are stimulators of pka and pkc, respectively, for their ability to provoke the phosphorylation of alpha-subunits of na,k-atpase in homogenates of xenopus o ... | 1992 | 1331053 |
| the beta subunit modulates potassium activation of the na-k pump. | we recently cloned the alpha 1 and the beta 1 and beta 3 subunits of the na,k-atpase of the toad bufo marinus. to investigate possible functional differences between beta 1 and beta 3, we studied the potassium activation of na-k pumps expressed in the oocyte of xenopus laevis. na-k pump activity was measured as k(+)-induced current in voltage-clamped oocytes. we could take advantage of the relative resistance to ouabain conferred by the bufo alpha subunit to study specifically the exogenously ex ... | 1992 | 1337667 |
| primary sequence and functional expression of a novel ouabain-resistant na,k-atpase. the beta subunit modulates potassium activation of the na,k-pump. | in order to understand the molecular mechanism of ouabain resistance in the toad bufo marinus, na,k-atpase alpha and beta subunits have been cloned and their functional properties tested in the xenopus laevis oocyte expression system. according to sequence comparison between species, alpha 1, beta 1, and beta 3 isoforms were identified in a clonal toad urinary bladder cell line (tbm 18-23). the sequence of the alpha 1 isoform is characterized by two positively charged amino acids (arg, lys) at t ... | 1992 | 1380956 |
| serotonin synthesis and accumulation by neurons of the anuran retina. | serotonin-synthesizing and serotonin-accumulating neurons were studied in the retinas of xenopus laevis and bufo marinus. all previously identified cell types exhibiting serotonin-like immunoreactivity (sli) were labeled by intravitreal injection of 5,7-dihydroxytryptamine (5,7-dht). they included two amacrine cell types (large and small) in both species, and one bipolar cell type in xenopus. incubation of retinas in culture medium in the ambient light reduced sli in amacrine cells and enhanced ... | 1992 | 1390395 |
| neuron-specific enolase-like immunoreactivity in the vertebrate retina: selective labelling of müller cells in anura. | neuron-specific enolase (nse) immunocytochemistry was carried out in retinae of goldfish, axolotl, clawed frog, cane toad, lizard, chick, guinea-pig, rabbit, rat, cat and human. with the exception of anura, strong immunoreactivity was seen in the large ganglion, amacrine cells and horizontal cells of the retina in all of the other species. photoreceptors were found to be labelled in the rat and human retina and only one cone type in rabbit. photoreceptor pedicles and ellipsoids were stained in t ... | 1992 | 1459864 |
| effect of carbenoxolone sodium on steroid-induced sodium transport in the toad bladder: further studies. | the licorice derivative, carbenoxolone sodium, is a potent inhibitor of the enzyme 11 beta-hydroxysteroid dehydrogenase. when this enzyme is suppressed or is absent, endogenous glucocorticoids induce mineralocorticoid-like sodium retention by the kidney. carbenoxolone sodium administered in vivo to an adrenalectomized rat has also recently been shown to enhance the mineralocorticoid response to submaximal concentrations of aldosterone, deoxycorticosterone (doc) and 11-dehydrocorticosterone (comp ... | 1992 | 1525050 |
| haematopoietic malignancies in zoo animals. | myelogenous leukaemia was found in a russell's viper, a honduran milk snake, a marine toad, a byrne's marsupial mouse and an african hedgehog. lymphocytic leukaemia was present in a broad banded copperhead and an indian lion. visceral lymphomatosis was observed in a snowy owl. | 1992 | 1556254 |
| distribution patterns and coexistence of neurohormonal peptides (anp, bnp, npy, sp, cgrp, enkephalins) in chromaffin cells and nerve fibers of the anuran adrenal organ. | immunohistochemical techniques were used to study the adrenal organs of the anuran species rana esculenta, caldula pulchra and bufo marinus with respect to the distribution and coexistence of atrial natriuretic peptide (anp), brain natriuretic peptide (bnp), substance p (sp), calcitonin gene-related peptide (cgrp), neuropeptide y (npy), leu-enkephalin (leu-enk). met-enkephalin-arg-phe (meap) and dynorphin a 1-17 (dyn). antisera against enzymes involved in catecholamine synthesis, i.e., dopamine- ... | 1992 | 1377603 |
| the role of hypoglossal sensory feedback during feeding in the marine toad, bufo marinus. | behavioral observations demonstrate that bilateral deafferentation of the hypoglossal nerves in the marine toad (bufo marinus) prevents mouth opening during feeding. in the present study, we used high-speed videography, electromyography (emg), deafferentation, muscle stimulation, and extracellular recordings from the trigeminal nerve to investigate the mechanism by which sensory feedback from the tongue controls the jaw muscles of toads. our results show that sensory feedback from the tongue ent ... | 1992 | 1431785 |
| the effect of adenosine on spontaneous and evoked quantal secretion from different release sites of amphibian motor-nerve terminals. | the effects of adenosine on the spontaneous quantal secretion from different release sites along terminal branches of toad (bufo marinus) motor-nerve terminals was studied. terminal branches were visualized using 3,3-diethyloxardicarbocyanine iodide (dioc2(5))-fluorescence to assist in the placement of extracellular electrodes along different release sites of terminal branches. the maximum rate of spontaneous secretions (fe) observed with an extracellular electrode within any 10 microns length o ... | 1992 | 1480323 |
| tissue distribution, elimination, and metabolism of [3h]leukotriene c4 by the conscious marine toad, bufo marinus. | tissue distribution, elimination, and metabolism of 3h-labelled leukotriene (lt) c4 were studied in ureter-catheterized conscious marine toads, bufo marinus. six and 24 h after injection, organs containing the highest percent of injected radioactivity were small intestine, liver, and kidney. radioactivity declined in these organs at 24 h by approximately threefold. peak elimination time for radioactivity in the urine was between 2 and 4 h after the injection. during the 24-h collection period, 5 ... | 1992 | 1338372 |
| spatial buffering of extracellular potassium by müller (glial) cells in the toad retina. | we examined the role of müller (glial) cells in buffering light-evoked changes in extracellular k+ concentration, [k+]o, in the isolated retina of the toad, bufo marinus. we found evidence for two opposing müller cell current loops that are generated by a light-evoked increase in [k+]o in the inner plexiform layer. these current loops, which are involved in the generation of the m-wave of the electroretinogram (erg), prevent the accumulation of k+ in the inner plexiform layer by transporting k+ ... | 1992 | 1483500 |
| insulin and igf1 receptors in a model renal epithelium: receptor localization and characterization. | insulin and igf1 stimulate transepithelial na+ transport in the urinary bladder of the toad bufo marinus, a model renal epithelium. the signal transduction mechanisms for the natriferic action are unknown. ultrastructural techniques were used to localize both receptors and ligands in the epithelium. electron microscopy using gold-labelled anti-insulin or anti-igf1 receptor antibodies demonstrated the majority of the insulin receptors were associated with the basolateral membrane while igf1 recep ... | 1992 | 1445387 |
| acid-base regulation in response to hypercapnia in the lymphatic and circulatory systems of the toad bufo marinus. | 1992 | 1402611 | |
| posterior lymph heart pressure and rate and lymph flow in the toad bufo marinus in response to hydrated and dehydrated conditions. | posterior lymph heart pressure, rate and flow were measured in chronically cannulated bufo marinus during normal hydrated and dehydrated conditions. a new surgical technique was developed which allowed direct and constant measurement of the functioning of the posterior lymph hearts with minimal disruption to normal lymph drainage. the mean intra-lymph-heart systolic pressure was 2.29 +/- 0.12 kpa for hydrated animals at rest, decreasing to 1.01 +/- 0.10 kpa after 24 h of dehydration. similarly, ... | 1992 | 1402607 |