Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| distribution of active protein kinase c in smooth muscle. | to localize activated protein kinase c (pkc) in smooth muscle cells, an antibody directed to the catalytic site of the enzyme was used to assess pkc distribution by immunofluorescence techniques in gastric smooth muscle cells isolated from bufo marinus. an antibody to vinculin was used to delineate the cell membrane. high-resolution three-dimensional images of immunofluorescence were obtained from a series of images collected through focus with a digital imaging microscope. cells were untreated ... | 1999 | 10423442 |
| skull allometry in the marine toad, bufo marinus. | scaling predictions pioneered by a.v. hill state that isometric changes in kinematics result from isometric changes in size. these predictions have been difficult to support because few animals display truly isometric growth. an exception to this rule is said to be the toads in the genus bufo, which can grow over three orders of magnitude. to determine whether skull shape increases isometrically, i used linear measurements and geometric morphometrics to quantify shape variation in a size series ... | 1999 | 10420158 |
| does adrenaline modulate the na+-ca2+ exchanger in isolated toad pacemaker cells? | beta-adrenergic stimulation of pacemaker cells from the sinus venosus of the cane toad (bufo marinus) increases intracellular calcium ([ca2+]i) and firing rate. the increase in [ca2+]i could contribute to the increased firing rate by increasing the inward na+-ca2+ exchange current (ina-ca) during diastole. in this study we measured [ca2+]i and membrane currents in single, isolated, voltage-clamped pacemaker cells. we show that ina-ca increases during beta-adrenergic stimulation. to test whether ... | 1999 | 10398864 |
| measurement of sarcoplasmic reticulum ca2+ content in intact amphibian skeletal muscle fibres with 4-chloro-m-cresol. | single skeletal muscle fibres were isolated from the toad (bufo marinus) and isometric force and myoplasmic free calcium concentration ([ca2+]i) were measured. brief applications of 4-chloro- m-cresol (4-cmc, 0.2-5 mm) elevated [ca2+]i reversibly in a dose-dependent manner. the lowest concentration of 4-cmc which reliably gave maximal [ca2+]i was 2 mm and it was, therefore, used for measurement of sarcoplasmic reticulum (sr) ca2+ content. tetanic stimulations (100 hz) increased [ca2+]i from a re ... | 1999 | 10378084 |
| how does beta-adrenergic stimulation increase the heart rate? the role of intracellular ca2+ release in amphibian pacemaker cells. | 1. the mechanism by which sympathetic transmitters increase the firing rate of pacemaker cells was explored in isolated cells from the sinus venosus of the cane toad bufo marinus. intracellular calcium concentration ([ca2+]i) was measured with indo-1 and membrane potential and currents were recorded with the nystatin perforated-patch technique. 2. adrenaline or isoprenaline (2 microm) increased the transient rise in [ca2+]i and increased the firing rate; these effects were blocked by propranolol ... | 1999 | 10200426 |
| quantal secretion and nerve-terminal cable properties at neuromuscular junctions in an amphibian (bufo marinus). | the effect of a conditioning depolarizing current pulse (80-200 micros) on quantal secretion evoked by a similar test pulse at another site was examined in visualized motor-nerve terminal branches of amphibian endplates (bufo marinus). tetrodotoxin (200 nm) and cadmium (50 microm) were used to block voltage-dependent sodium and calcium conductances. quantal release at the test electrode was depressed at different distances (28-135 microm) from the conditioning electrode when the conditioning and ... | 1999 | 10085340 |
| responses of single neurons in the toad's caudal ventral striatum to moving visual stimuli and test of their efferent projection by extracellular antidromic stimulation/recording techniques. | previous work in anuran amphibians has shown that activity in the caudal ventral striatum correlates with visuomotor activity: orienting responses toward prey fail to occur after striatal lesions. thus it has been suggested that the striatum influences visually guided behavior. therefore, the present study investigates visual response properties from neurons recorded in the striatum. extracellular recordings of 104 single neurons of the cane toad's (bufo marinus) caudal ventral striatum (str) re ... | 1999 | 10681604 |
| an electrophoretic study of myosin heavy chain expression in skeletal muscles of the toad bufo marinus. | in this study we developed an sds-page protocol which for the first time separates effectively all myosin heavy chain (mhc) isoforms expected to be expressed in iliofibularis (if), pyriformis (pyr), cruralis (cru) and sartorius (sar) muscles of the toad bufo marinus on the basis of previously reported fibre type composition. the main feature of the method is the use of alanine instead of glycine both in the separating gel and in the running buffer. the correlation between the mhc isoform composi ... | 1999 | 10672517 |
| lung deflation stimulates fictive ventilation in decerebrated and unidirectionally ventilated toads. | we describe how the degree of lung inflation and hypercapnia influenced fictive ventilation in five toads (bufo marinus) that were decerebrated and paralysed with roccuronium. both lungs were unidirectionally ventilated and the degree of lung inflation was determined by controlling the outflow resistance of these catheters, while ventilatory motor output was assessed on the basis of nervous activity in the mandibular branch of the vth cranial nerve. the pattern of the recorded activity ('fictive ... | 1999 | 10647862 |
| salt sensitivity and hydration behavior of the toad, bufo marinus. | toads, bufo marinus, were placed on laboratory tissue saturated with water or with hyperosmotic (250 or 500 mm nacl or kcl) solutions, and their behavior was observed for 5 min. toads placed on water initially allowed their ventral skin to touch the surface without abducting the hind limbs. during this "seat patch down" (spd) behavior toads appeared to be evaluating the suitability of a hydration source prior to initiating "water absorption response" (wr) behavior with the hind limbs fully abduc ... | 1999 | 10604846 |
| intracellular calcium during fatigue of cane toad skeletal muscle in the absence of glucose. | mechanisms of fatigue were studied in single muscle fibres of the cane toad (bufo marinus) in which force, intracellular calcium ([ca2+]i), [mg2+]i, glycogen and the rapidly releasable ca2+ from the sarcoplasmic reticulum (sr) were measured. fatigue was produced by repeated tetani continued until force had fallen to 50%. two patterns of fatigue in the absence of glucose were studied. in the first fatigue run force fell to 50% in 8-10 min. fatigue runs were then repeated until force fell to 50% i ... | 2000 | 11129439 |
| polymerase chain reaction primers for polymorphic microsatellite loci in the invasive toad species bufo marinus. | 2000 | 11091334 | |
| absence of evidence for isolation by distance in an expanding cane toad (bufo marinus) population: an individual-based analysis of microsatellite genotypes. | the cane toad (bufo marinus) was introduced in 1935 in australia, where it spread rapidly. we have tested for isolation by distance by analysing at a local geographical scale a continuous population using seven microsatellite markers and an individual-based method. the matrix of pairwise individual differentiation was not significantly correlated with that of geographical distance. regression analyses gave a low positive slope of 0.00072 (all individuals) or a negative slope of 0.0017 (individua ... | 2000 | 11091326 |
| hindlimb extensor muscle function during jumping and swimming in the toad (bufo marinus). | many anurans use their hindlimbs to generate propulsive forces during both jumping and swimming. to investigate the musculoskeletal dynamics and motor output underlying locomotion in such physically different environments, we examined patterns of muscle strain and activity using sonomicrometry and electromyography, respectively, during jumping and swimming in the toad bufo marinus. we measured strain and electromyographic (emg) activity in four hindlimb muscles: the semimembranosus, a hip extens ... | 2000 | 11060216 |
| potentiation by neostigmine of responses to vagal nerve stimulation in the sinus venosus of the toad. | the effects of the cholinesterase inhibitor neostigmine on the responses to vagus nerve stimulation of isolated sinus venosus/atrial preparations of the toad, bufo marinus, were examined. in control solutions, trains of stimuli applied to the vagus nerve led to a decrease in heart rate that was susceptible to muscarinic receptor blockade. membrane potential recordings made from sinus venosus cells showed that the responses to trains of stimuli, delivered at frequencies of less than 10 hz, were l ... | 2000 | 11023616 |
| the mechanisms of sarcoplasmic reticulum ca2+ release in toad pacemaker cells. | the mechanisms of sarcoplasmic reticulum (sr) ca2+ release in pacemaker cells from the sinus venosus of the cane toad (bufo marinus) were studied. single, isolated cells were voltage clamped using a nystatin-perforated patch. ionic currents and intracellular ca2+ concentration ([ca2+]i) were recorded simultaneously. depolarizations of 300 ms duration from a holding potential of -55 mv produced an inward current which had a bell-shaped relationship with voltage. inward current first appeared at a ... | 2000 | 10856122 |
| pulmonary vagal modulation of ventilation in toads (bufo marinus). | this study examined the role of pulmonary vagal feedback on hypercapnic chemosensitivity and breathing pattern formation in cane toads (bufo marinus). decerebrate, paralysed toads were uni-directionally ventilated with air, 2.5% co(2) or 5.0% co(2) with the lungs inflated or deflated, before and after pulmonary vagotomy. motor output from the mandibular branch of the trigeminal nerve served as an index of fictive breathing. as respiratory drive was increased, breathing frequency increased and br ... | 2000 | 10828339 |
| mitochondrial ca2+ homeostasis during ca2+ influx and ca2+ release in gastric myocytes from bufo marinus. | 1. the ca(2+)-sensitive fluorescent indicator rhod-2 was used to monitor mitochondrial ca2+ concentration ([ca2+]m) in gastric smooth muscle cells from bufo marinus. in some studies, fura-2 was used in combination with rhod-2, allowing simultaneous measurement of cytoplasmic ca2+ concentration ([ca2+]i) and [ca2+]m, respectively. 2. during a short train of depolarizations, which causes ca2+ influx from the extracellular medium, there was an increase in both [ca2+]i and [ca2+]m. the half-time (t1 ... | 2000 | 10713963 |
| ca(2+) channel-mediated currents in retinal glial (müller) cells of the toad (bufo marinus). | whole-cell voltage-clamp recordings were used to detect voltage-gated ca(2+) channels in freshly isolated retinal glial (müller) cells of the toad (bufo marinus). using ca(2+) ions (2 mm) as charge carriers (in the presence of 1 mm mg(2+)), no inwardly directed currents could be observed during the application of depolarizing voltage steps. however, after omitting the divalent cations from the bath solution, large-amplitude inwardly directed currents were evoked that were carried by na(+) ions, ... | 2000 | 10704766 |
| rapid light-induced changes in near infrared transmission of rods in bufo marinus. | rapid transient changes in axial transmission of near infrared light through the outer segments of retinal rods of bufo marinus are induced by illumination. the reasons for these changes are not clear. the changes in optical transmission may be useful in the study of photoreceptor function. however, the study of photoreceptor functions through the use of indicator dyes may be confounded by the intrinsic light-induced changes of optical properties of the photoreceptor cells. | 2000 | 102035 |
| effects of 3'deoxyadenosine and actinomycin d on rna synthesis in toad bladder: analysis of response to aldosterone. | previous studies have shown that aldosterone increases transepithelial active na+ transport after a latent period of about 60 min and incorporation of 3h-uridine into polyadenylated rna (poly(a)(+)rna) (putatively poly(a)(+)mrna) as early as 30 min after aldosterone addition. to assess the physiological importance of this pathway, the effects of 3'deoxyadenosine and actinomycin d were compared in studies on the urinary bladder of the toad bufo marinus. 3'deoxyadenosine (30 microgram/ml) only par ... | 2000 | 97386 |
| surface emg-recordings using a miniaturised matrix electrode: a new technique for small animals. | a new method for multichannel surface-emg measurements in small animals is presented. the underlying scientific aim is the characterisation of the spreading and the co-ordination of skeletal muscle activation between different muscles or muscle parts, depending on various motor tasks. the myoelectrical signals were recorded monopolarly by a 16-channel matrix electrode on the muscle surface directly under the skin on the fascia of the investigated muscle, without damaging the muscle. surface-emg' ... | 2000 | 10771077 |
| whole-body systemic transcapillary filtration rates, coefficients, and isogravimetric capillary pressures in bufo marinus and rana catesbeiana. | whole-body and organ-level transcapillary filtration rates and coefficients are virtually unexamined in ectothermal vertebrates. these filtration rates appear to be greater than in mammals when plasma volume shifts and lymphatic function are analyzed. gravimetric techniques monitoring whole-body mass changes were used to estimate net systemic filtration in bufo marinus and rana catesbeiana while perfusing with low-protein ringer's and manipulating venous pressure. capillary pressures were estima ... | 2000 | 10801394 |
| bufo marinus intoxication in dogs: 94 cases (1997-1998). | to determine history, clinical and electrocardiographic abnormalities, treatment, and outcome of dogs exposed to toxins produced by the bufo marinus toad. | 2000 | 10863593 |
| structure of the 5th transmembrane segment of the na,k-atpase alpha subunit: a cysteine-scanning mutagenesis study. | to study the structure of the pathway of cations across the na, k-atpase, we applied the substituted cysteine accessibility method to the putative 5th transmembrane segment of the alpha subunit of the na,k-atpase of the toad bufo marinus. only the most extracellular amino acid position (a(796)) was accessible from the extracellular side in the native na,k-pump. after treatment with palytoxin, six other positions (y(778), l(780), s(782), p(785), e(786) and l(791)), distributed along the whole len ... | 2000 | 11018538 |
| amphibian choroid plexus lipocalin, cpl1. | choroid plexus lipocalin 1 (cpl1) has been isolated from the african clawed toad (xenopus laevis) and the cane toad (bufo marinus). xcpl1 has been used as a marker for studying early neural development. due to its retinoid binding properties and the fact that it causes dysmorphogenesis when overexpressed in the early embryo, the protein product is considered to be part of the retinoic acid signalling pathway. later in development and during adulthood, the epithelial cell sheet of the choroid ple ... | 2000 | 11058754 |
| bufokinin: actions and distribution in the toad cardiovascular system. | 1. bufokinin is a substance p-like neuropeptide and potent spasmogen isolated from the intestine of the cane toad bufo marinus. in the present study, we investigated the effects of bufokinin on systemic blood pressure and heart rate in the anaesthetized toad and the distribution of bufokinin-like immunoreactivity in the toad vasculature. 2. intravenous bufokinin caused a dose-dependent fall in systemic blood pressure (maximum fall 20 mmhg) with an ed50 of 2.9 pmol. at higher doses, the effect wa ... | 2000 | 11071309 |
| atrial natriuretic peptide binding sites in the brain and pituitary gland of the toad, bufo marinus: localisation and receptor characterisation. | the distribution and nature of 125i-atrial natriuretic peptide binding sites have been examined in the brain and pituitary gland of the toad, bufo marinus, using tissue section autoradiography, affinity cross-linking and electrophoresis, guanylyl cyclase assays and molecular analysis of natriuretic peptide receptor c (npr-c) and npr-gc mrna expression. the highest density of 125i-atrial natriuretic peptide binding sites occurred in the dorsal pallium, the habenular region, the torus semicircular ... | 2000 | 11079720 |
| islet hormones from the african bullfrog pyxicephalus adspersus (anura:ranidae): structural characterization and phylogenetic implications. | the african bullfrog pyxicephalus adspersus is generally classified along with frogs of the genus rana in the subfamily raninae of the family ranidae but precise phylogenetic relationships between species are unclear. pancreatic polypeptide (pp), insulin, and glucagon-like peptide (glp-1) were isolated from an extract of p. adspersus pancreas and characterized structurally. a comparison of the amino acid sequence of pyxicephalus pp (apsepqhpgg(10)qatpeqlaqy(20)ysdlyqyitf(30)itrprf++ +. nh(2)) wi ... | 2000 | 10882553 |
| effect of temperature on ph and electrolyte concentration in air-breathing ectotherms. | the aim of this study was to determine the effects of temperature upon ph, protein charge and acid-base-relevant ion exchange in air-breathing ectotherms. plasma and skeletal muscles in cane toads (bufo marinus) and bullfrogs (rana catesbeiana) were examined at 30, 20 and 10 degrees c. in addition, skeletal muscle ion concentrations were examined in black racer snakes (coluber constrictor) at 30 and 10 degrees c. cooling the amphibians produced a reduction in most of the plasma ion concentration ... | 2000 | 10851123 |
| natriuretic peptide receptors in the central vasculature of the toad, bufo marinus. | natriuretic peptide receptors in the central vasculature of the toad, bufo marinus, were characterized using autoradiographical, molecular, and physiological techniques. specific 125i-rat anp binding sites were present in the carotid and pulmonary arteries, the lateral aorta, the pre- and post-cava, and the jugular vein, and generally occurred in each layer of the blood vessel. the 125i-rat anp binding was partially displaced by the specific natriuretic peptide receptor c ligand, c-anf, which in ... | 2001 | 11223387 |
| the blood parasites of anurans from costa rica with reflections on the taxonomy of their trypanosomes. | during may 1997, specimens of 7 species of anurans, that included 5 phrynohyas venulosa laurenti, 5 rana forreri boulenger, 7 rana vaillanti brucchi, 6 eleutherodactylus fitzingeri schimdt, 4 smilisca baudinii duméril and bibron, 1 leptodactylus melanonotus, and 3 bufo marinus linneaus, from the guanacaste conservation area, costa rica were examined for blood parasites. their hematozoan fauna included intraerythrocytic and intraleukocytic icosahedral viruses, a rickettsia (aegyptianella sp.), 2 ... | 2001 | 11227883 |
| salmonelliasis in wildlife from queensland. | during a 20 yr period (1978 to 1998), 233 isolates of salmonella spp. were cultured from 179 wildlife animals (representing 25 species), 32 crocodile (crocodylus porosus) eggs and six crocodile nesting sites, and represented 59 different serotypes. salmonella serotype virchow, the major serotype infecting humans in north queensland, (australia) was common in macropodids, but was not found in reptiles and was isolated only once from cane toads (bufo marinus). investigations of human cases of salm ... | 2001 | 11310872 |
| amphibian glucagon family peptides: potent metabolic regulators in fish hepatocytes. | peptides analogous to glucagon-like peptide-1 (glp-1) have been isolated from amphibian pancreas and intestine, and their amino acid sequences and cdna structures elucidated. just like their mammalian counterpart, these peptides are potent insulinotropins in mammalian pancreatic cells. we show here that these peptides also exert strong glycogenolytic actions when applied to dispersed fish hepatocytes. we compared the potencies of three synthetic glp-1s from xenopus laevis and two native glp-1s f ... | 2001 | 11384772 |
| glypthelmins poncedeleoni n. sp. (trematoda: macroderoididae) of amphibians from the neotropical region of méxico. | a new species of glypthelmins (trematoda: macroderoididae) is described from the intestine of bufo marinus and leptodactylus melanonotus from several localities of the neotropical region of mexico. glypthelmins poncedeleoni n. sp. can be differentiated from other species of the genus by having extracecally distributed vitellaria, ovary always larger than testes, and vitelline follicles grouped in 7 post-testicular, nonoverlapping, rosette-like clusters and 5 pretesticular overlapping clusters. | 2001 | 11426736 |
| the acute toxicity of agricultural surfactants to the tadpoles of four australian and two exotic frogs. | nonionic surfactants are frequently incorporated into pesticide formulations, and are therefore a group of chemicals to which amphibians may be exposed in agricultural or urban landscapes. however, little is known about the effects of surfactant exposure in amphibians. feeding stage tadpoles of bufo marinus, xenopus laevis and four species of australian frogs (crinia insignifera, heleioporus eyrei, limnodynastes dorsalis and litoria moorei) were exposed to nonylphenol ethoxylate (npe) and alcoho ... | 2001 | 11504342 |
| ultrastructure of developmental stages of hemolivia stellata (apicomplexa: haemogregarinidae) in the cane toad bufo marinus and in its vector tick amblyomma rotondatum. | the fine structure of the hemogregarine hemolivia stellata petit, landau, baccam and lainson, 1990 developmental stages in the cane toad bufo marinus l. and the vector tick amblyomma rotondatum koch, 1844 are described. in the liver of the toad, merozoites bound by a pellicle were located free and in the cytoplasm, and young and encased mature polynucleated meronts were located in a parasitophorous vacuole (pv). premature gametocytes in the erythrocytes were bound by a bilayered membranous wall ... | 2001 | 11510993 |
| bufo marinus bladder h-k-atpase carries out electroneutral ion transport. | bufo marinus bladder h-k-atpase belongs to the na-k-atpase and h-k-atpase subfamily of oligomeric p-type atpases and is closely related to rat and human nongastric h-k-atpases. it has been demonstrated that this atpase transports k(+) into the cell in exchange for protons and sodium ions, but the stoichiometry of this cation exchange is not yet known. we studied the electrogenic properties of b. marinus bladder h-k-atpase expressed in xenopus laevis oocytes. in a hepes-buffered solution, k(+) ac ... | 2001 | 11592945 |
| cellular cl content and concentration of amphibian skeletal and heart muscle. | toads (bufo marinus) and frogs (rana pipiens pipiens) were given intraperitoneal injections of na36cl and na235so4. after in vivo equilibration for 20--180 min, the animals were pithed, and their ventricular and semitendinosus muscles were excised. measurements of total cl (by titrimetry) and 36cl (by radioassay) showed that specific radioactivities of plasma and mus les approached equality within 1 h after injection for toad skeletal and heart muscle and frog ventricles, indicating complete exc ... | 2001 | 100012 |
| reversible inhibition by lanthanum of the hydrosmotic response to serosal hypertonicity in toad urinary bladder. | in the urinary bladder of amphibia, hypertonicity of the serosal bath (sh) evokes an increase in transepithelial water permeability, the characteristics of which resemble the response to antidiuretic hormone (adh). the ionic dependency, in particular for ca2+, appears very similar for sh- and adh-induced water fluxes. in the present experiments la3+ was used as a probe to study the ca2+-dependency of the hydrosmotic response to sh in isolated urinary bladder of the toad bufo marinus. addition of ... | 2001 | 114663 |
| sympathetic innervation of the spleen of the cane toad, bufo marinus. | 2001 | 30569 | |
| molecular activity of na(+)/k(+)-atpase from different sources is related to the packing of membrane lipids. | the activity of the ubiquitous na(+)/k(+)-atpase represents a substantial portion of the resting metabolic activity of cells, and the molecular activity of this enzyme from tissues of different vertebrates can vary several-fold. microsomes were prepared from the kidney and brain of the rat (rattus norvegicus) and the cane toad (bufo marinus), and na(+)/k(+)-atpase molecular activity was determined. the membrane lipids surrounding this enzyme were isolated and phospholipids prepared. 'surface pre ... | 2001 | 11815651 |
| short-term storage of cane toad (bufo marinus) gametes. | the responses of cane toad (bufo marinus) gametes, used as a model for the development of assisted reproduction techniques for rare and endangered amphibians, to short-term storage at temperatures > 0 degrees c were studied. whole excised testes were stored at 0 degrees or 4 degrees c for 15 days, and sperm motility was measured at excision and after storage for 2, 5, 7, 10, 12 and 15 days. spermatozoa showed > 50% motility for 7 days at 0 degrees c and for 5 days at 4 degrees c. at 15 days, onl ... | 2001 | 11226040 |
| structural and mechanical aspects of the skin of bufo marinus (anura, amphibia). | specific biomechanical characters and some structures possibly related to them were investigated in the skin of the toad bufo marinus using tensile testing techniques (at constant strain till rupture) as well as morphological methods (histological, immunohistochemical and electronmicroscopical). mechanical parameters of the native skin varied considerably according to sex, individual variability and/or site of specimen collection. in skin strips of males and females excised from different parts ... | 2001 | 11949790 |
| [new observations on the structure of the lingual filiform papillae epithelium of the toad bufo marinus l.: light and transmission electron microscopy study]. | there are several inconsistencies and confusions about the microscopic structure in the anurans dorsal, non-sensory, mucosal epithelium of the tongue. the aim of this work was to differentiate the structure of the epithelium covering filiform papillae from the glandular epithelium. for this, samples of the dorsal distal mucosa of bufo marinus tongue were processed for light microscopy (lm) and transmission electron microscopy (tem). for lm, stained 1 micron sections were used. the results showed ... | 2001 | 11915447 |
| inferring population history from microsatellite and enzyme data in serially introduced cane toads, bufo marinus. | much progress has been made on inferring population history from molecular data. however, complex demographic scenarios have been considered rarely or have proved intractable. the serial introduction of the south-central american cane toad bufo marinus in various caribbean and pacific islands involves four major phases: a possible genetic admixture during the first introduction, a bottleneck associated with founding, a transitory population boom, and finally, a demographic stabilization. a large ... | 2001 | 11779806 |
| the dynamics of venous return and response to hypervolemia in the toad, bufo marinus (l.). | venous return from the posterior region of amphibians travels by either two renal portal veins to the kidney or a central abdominal vein that drains into the hepatic portal system. the relative proportions of blood flow in these vessels has never been measured nor has a modification of flow been determined when venous return increases by changes in blood volume during hypervolemia or during increased volume input from the posterior lymph hearts. | 2001 | 11696249 |
| parallel metabotropic pathways in the heart of the toad, bufo marinus. | this study examined the transduction pathways activated by epinephrine in the pacemaker region of the toad heart. recordings of membrane potential, force, and intracellular ca(2+) concentration ([ca(2+)](i)) were made from arrested toad sinus venosus. sympathetic nerve stimulation activated non-alpha-, non-beta-adrenoceptors to evoke a membrane depolarization and a transient increase in [ca(2+)](i). in contrast, the beta-adrenoceptor agonist isoprenaline (10 microm) caused membrane hyperpolariza ... | 2001 | 11557570 |
| effects of ozone on evaporative water loss and thermoregulatory behavior of marine toads (bufo marinus). | ozone (o(3)) is a strong pulmonary irritant and causes a suite of respiratory tract inflammatory responses in humans and other mammals. in addition to lung injury, rodents exposed to o(3) exhibit a pronounced decrease in core body temperature at rest, which may offer a protective effect against o(3) damage. the effects of o(3) on other vertebrates have not been studied. compared to individuals exposed to air (n=34), bufo marinus toads exposed to o(3) (n=32) for 4 h lost 3.78 g body mass (adjuste ... | 2001 | 11453678 |
| the use of the indicator fluo-5n to measure sarcoplasmic reticulum calcium in single muscle fibres of the cane toad. | 1. single fibres from the lumbrical muscles of the cane toad (bufo marinus) were incubated in fluo-5n am for 2 h at 35 degrees c in order to load the indicator into the sarcoplasmic reticulum. fluo-5n is a low-affinity calcium indicator (k(ca) 90 microm). successful sarcoplasmic reticulum (sr) loading was indicated by a fluorescence signal that declined during contraction. 2. confocal microscopy showed that the dye loaded principally in lines perpendicular to the long axis of the fibre that repe ... | 2001 | 11432994 |
| effects of membrane cholesterol manipulation on excitation-contraction coupling in skeletal muscle of the toad. | 1. single mechanically skinned fibres and intact bundles of fibres from the twitch region of the iliofibularis muscle of cane toads were used to investigate the effects of membrane cholesterol manipulation on excitation-contraction (e-c) coupling. the cholesterol content of membranes was manipulated with methyl-beta-cyclodextrin (mbetacd). 2. in mechanically skinned fibres, depletion of membrane cholesterol with mbetacd caused a dose- and time-dependent decrease in transverse tubular (t)-system ... | 2001 | 11432993 |
| effects of temperature and oxygen availability on circulating catecholamines in the toad bufo marinus. | the release of catecholamines during hypoxia has received limited attention in amphibians and the adrenergic regulation of cardio-pulmonary functions is, therefore, not well understood at the organismic level. to describe the changes in plasma catecholamine concentrations, we exposed toads (bufo marinus) to different levels of hypoxia at two temperatures (15 and 25 degrees c). in addition, blood oxygen binding properties were determined in vitro at 15 and 25 degrees c at two different ph values. ... | 2001 | 11423317 |
| lymph osmolality and rehydration from nacl solutions by toads, bufo marinus. | toads, bufo marinus, allowed to maintain an ad libitum state of hydration were dehydrated by 10 15% of their standard weight and allowed to rehydrate from either deionized water or from 10 or 50 mmol l(-1) nacl solutions. toads rehydrating from the dilute salt solutions recovered a larger fraction of their standard weight than did toads rehydrating from deionized water despite there being a reduced osmotic gradient. amiloride did not reduce water gain from these solutions. water uptake from 100 ... | 2001 | 11409625 |
| alpha2 adrenergic receptors and the central control of breathing in the cane toad, bufo marinus. | the effect of adrenergic agents on the central control of breathing in the cane toad, bufo marinus, was tested by applying adrenergic agents to the ventral medullary surface of decerebrate adult toads. toads were unidirectionally ventilated while recording lung, buccal, and artery blood pressures (bpi), as well as heart rate (hr). following a control period, filter paper pledgets soaked in the appropriate solution (epinephrine - 0.023, 0.05, 0.10, and 0.23 mm; norepinephrine - 0.002, 0.016, 0.03 ... | 2001 | 11282388 |
| involvement of cholinergic mechanisms in the central control of respiration in the cane toad, bufo marinus. | chemical substrates, central sites and central mechanisms underlying the regulation of breathing in lower vertebrates have not been well characterized. the present study was undertaken to determine the effect of ph changes and cholinergic agents on the central control of respiration in the cane toad, bufo marinus. adult toads were anesthetized, catheterized and unidirectionally ventilated before exposing the brainstem. an airtight buccal cannula was also inserted through the tympanum to record b ... | 2001 | 11282326 |
| formation and function of synapses with respect to schwann cells at the end of motor nerve terminal branches on mature amphibian (bufo marinus) muscle. | a study has been made of the formation and regression of synapses with respect to schwann cells at the ends of motor nerve terminal branches in mature toad (bufo marinus) muscle. synapse formation and regression, as inferred from the appearance and loss of n-(3-triethylammoniumpropyl)-4-(4-(dibutylamino)styryl) pyridinium dibromide (fm1-43)-stained vesicle clusters, occurred at the ends of terminal branches over a 16 hr period. multiple microelectrodes placed in an array about fm1-43 blobs at th ... | 2001 | 11264312 |
| cysteine-scanning mutagenesis study of the sixth transmembrane segment of the na,k-atpase alpha subunit. | the accessibility of the residues of the sixth transmembrane segment (tm) of the bufo marinus na,k-atpase alpha subunit was explored by cysteine scanning mutagenesis. methanethiosulfonate reagents reached only the two most extracellular positions (t803, d804) in the native conformation of the na,k-pump. palytoxin induced a conductance in all mutants, including d811c, t814c and d815c which showed no active electrogenic transport. after palytoxin treatment, four additional positions (v805, l808, d ... | 2002 | 11904164 |
| effects of anaesthesia on blood gases, acid-base status and ions in the toad bufo marinus. | it is common practice to chronically implant catheters for subsequent blood sampling from conscious and undisturbed animals. this method reduces stress associated with blood sampling, but anaesthesia per se can also be a source of stress in animals. therefore, it is imperative to evaluate the time required for physiological parameters (e.g. blood gases, acid-base status, plasma ions, heart rate and blood pressure) to stabilise following surgery. here, we report physiological parameters during an ... | 2002 | 11867289 |
| bidder's organ in the toad bufo marinus: effects of orchidectomy on the morphology and expression of lamina-associated polypeptide 2. | the bidder's organ is an undeveloped ovary located anterior to the testis in male true toads (bufonidae). the presence of sperm and oocytes, derived from the primordial germ cells of the male toad, provides an exceptional condition for the study of germ cell differentiation in vertebrates. in this study, the effects of orchidectomy on morphology and on lamina-associated polypeptide 2 (lap2) expression were investigated in the bidder's organ of bufo marinus. to characterize bidderian oocytes, oog ... | 2002 | 12492511 |
| storage of cane toad (bufo marinus) sperm for 6 days at 0 degrees c with subsequent cryopreservation. | we investigated the recovery of motility of cane toad (bufo marinus) sperm after storage for 6 days at 0 degree c (on ice) and after subsequent cryopreservation. sperm suspensions were prepared from testes macerated in either simplified amphibian ringer (sar) or 10% (w/v) sucrose diluents, with 15% or 20% (v/v) glycerol or me2so as cryoprotectants, and were stored for 6 days. alternatively, suspensions were prepared in either sar or 10% (w/v) sucrose diluent and stored for 6 days, after which so ... | 2002 | 12467350 |
| limb preference and skeletal asymmetry in the cane toad, bufo marinus (anura: bufonidae). | two forms of skeletal asymmetry were identified in a population of cane toads, bufo marinus, an exotic species in australia. fluctuating asymmetry characterised the lengths and weights of the long bones of the forelimbs and hindlimbs. directional asymmetry was observed in the structure of the pectoral girdle of the toads, with the right epicoracoid positioned ventral to the left epicoracoid in 88% of the skeletons examined. morphological data from a cohort of individuals were correlated with lim ... | 2002 | 15513201 |
| [suggestive evidences for a microanatomical relationship between mast cells and nerve in the tongue of the toad bufo marinus demonstrated by means of high resolution light microscopy]. | mast cells are connective tissue cells, present in all vertebrates and characterized by the metachromatic stain of their granules. nowadays mast cells have been recognized as a potent cellular source of multiple cytokines, suggesting an important role in immunoregulation and host defense. these cells have been described as preferentially located around blood vessels but more recently close spatial relationship between mast cells and nerves has been reported mostly in mammalian species. the micro ... | 2002 | 12945491 |
| lymph heart scintigraphy in the toad. | to our knowledge, there are no reports on the use of radionuclide labeled agents to image the lymphatic system of anuran amphibia. lymphoscintigraphy was performed in 18 toads bufo marinus l, after the injection of tc-99m-serum albumin within the ventral lymph sac. images were obtained with a rectilinear scanner immediately after tracer administration. scintigrams were digitalized and densitometric profiles were obtained. one or more lymph hearts were demonstrated on all 18 scans. scintigrams sh ... | 2002 | 12570327 |
| myosin heavy chain isoform expression and ca2 +-stimulated atpase activity in single fibres of toad rectus abdominis muscle. | segments of single fibres from the rectus abdominis (ra) muscles of adult and juvenile cane toads (bufo marinus) were examined for myosin heavy chain (mhc) isoform expression and ca2+-stimulated mgatpase activity. mhc isoform analyses were carried out using the recently developed alanine-sds-page method, which separates one tonic (bmhct) and three twitch (bmhc1, bmhc2, bmhc3) mhc isoforms in toad skeletal muscle. ca2+-stimulated mgatpase activity was measured by spectrophotometric determination ... | 2002 | 12416721 |
| a comparison of sucrose, saline, and saline with egg-yolk diluents on the cryopreservation of cane toad (bufo marinus) sperm. | previous studies on cane toad (bufo marinus; bufonidae; anura) sperm cryopreservation were extended to compare the effects of cryopreservation in established sucrose (non-ionic) diluents with cryopreservation in ionic diluents containing amphibian ringer solutions (with and without egg-yolk). in addition, methanol was tested as a cryoprotectant for b. marinus sperm for the first time. twenty-seven cryoprotective solutions were trialled, with each containing one of the three diluents [10% (w/v) s ... | 2002 | 12237090 |
| [the glands of the dorso-distal mucosa of the toad bufo marinus (amphibia: anura) tongue: histology and ultrastructure ]. | frequently, the studies on the lingual epithelium ultrastructure in anurans do not show differences between filiform papilae and glandular epithelia in the non-sensory dorsal epithelium. to accomplish the study of glandular epithelium, samples of dorso-distalis mucosae of bufo marinus tongue were processed for transmission electron microscopy and also semithin sections of the same material were used for light microscopy study. the results showed that the glandular epithelium is constituted by th ... | 2002 | 12216500 |
| atp suppresses activity in slowly adapting but not rapidly adapting mechanoreceptors in toad skin. | to test the possible role of atp in transducing or modulating touch sensation, an isolated skin-nerve preparation from the toad, bufo marinus, perfused on the inner side, was used to examine the effects of atp on slowly adapting (sa) and rapidly adapting (ra) mechanoreceptors, identified by ramp and hold indentation of the skin. atp (1-50 mm) did not generate impulse activity in either sa or ra mechanoreceptors nor increase their responses to mechanical stimulation. instead, atp (> or =5 mm) rev ... | 2002 | 12167770 |
| electrophysiological properties of the tongue epithelium of the toad bufo marinus. | the dorsal lingual epithelium from the tongue of the toad bufo marinus was mounted in an ussing-type chamber, and the short-circuit current (i(sc)) was measured using a low-noise voltage clamp. with nacl ringer bathing the mucosal and serosal surfaces of the isolated tissue, an outwardly directed (mucosa-positive) i(sc) was measured that averaged -10.71+/-0.82 microa cm(-2) (mean +/- s.e.m., n=24) with a resistance of 615+/-152 omega cm(2) (mean +/- s.e.m., n=10). substitution of chloride with s ... | 2002 | 12077171 |
| cladistic analysis of anuran pomc sequences. | procedures for performing cladistic analyses can provide powerful tools for understanding the evolution of neuropeptide and polypeptide hormone coding genes. these analyses can be done on either amino acid data sets or nucleotide data sets and can utilize several different algorithms that are dependent on distinct sets of operating assumptions and constraints. in some cases, the results of these analyses can be used to gauge phylogenetic relationships between taxa. selecting the proper cladistic ... | 2002 | 11835993 |
| functional analysis of natriuretic peptide receptors in the bladder of the toad, bufo marinus. | this study aimed to localize and characterize natriuretic peptide binding sites in the urinary bladder of bufo marinus and to then examine the effect of natriuretic peptides on the bladder vascular tone and water reabsorption in isolated perfused bladder preparations. specific (125)i-rat atrial natriuretic peptide ((125)i-ranp) binding sites were present on blood vessels, muscle, and epithelium. in tissue sections and/or isolated membranes, the binding was completely displaced by frog anp, rat a ... | 2002 | 11884066 |
| lamina-associated polypeptide 2 (lap2) expression in fish and amphibians. | somatic and germinal cells of 15 fish and 33 amphibian species were examined by sds-page followed by immunoblotting to determine the expression of lap2 (lamina-associated polypeptide 2). lap2 expression in frogs, salamanders and fish does not vary with the mode of reproduction. in fish and frog cells, a rim-like lap2 positive region was detected around the nucleus by indirect immunofluorescence microscopy. the cell distribution and expression patterns of lap2 in fish, frogs and salamanders are c ... | 2002 | 11934151 |
| the short-term storage and cryopreservation of spermatozoa from hylid and myobatrachid frogs. | the short-term storage (at 0 degrees c) and cryopreservation of spermatozoa may be useful for providing gametes for fertilisations performed in programmes for the conservation and management of endangered amphibians. the current study was undertaken to examine the applicability of amphibian spermatozoa storage protocols developed with the cane toad (bufo marinus) to a wider range of amphibian species, with a view to ultimately using these protocols for endangered species. in australia, at least ... | 2002 | 12050781 |
| identification of a fourth opioid core sequence in a prodynorphin cdna cloned from the brain of the amphibian, bufo marinus: deciphering the evolution of prodynorphin and proenkephalin. | in mammals, prodynorphin codes for three c-terminally extended forms of leu-enkephalin. this is not the case for the anuran amphibian, bufo marinus. a combination of 3'race, rt-pcr and 5'race protocols was used to clone and characterize a prodynorphin cdna from the brain of this amphibian that contained two met-enkephalin sequences. one met-enkephalin sequence was located at the n-terminal of met(5)-dynorphin a(1-17), and the other met-enkephalin sequence was located in the n-terminal region of ... | 2002 | 12097817 |
| nitric oxide regulation of the central aortae of the toad bufo marinus occurs independently of the endothelium. | nitric oxide (no) signalling pathways were examined in the lateral aortae and dorsal aorta of the cane toad bufo marinus. nadph diaphorase histochemistry and nitric oxide synthase (nos) immunohistochemistry found no evidence for endothelial nos in the endothelium of toad aortae, but it could be readily demonstrated in rat aorta that was used as a control. immunohistochemistry using a specific neural nos antibody showed the presence of neural nos immunoreactivity in the perivascular nerves of the ... | 2002 | 12200412 |
| the primary structures and myotropic activities of two tachykinins isolated from the african clawed frog, xenopus laevis. | two peptides with limited structural similarity to mammalian substance p (sp) and neurokinin a (nka) have been isolated from extracts of the intestine of the african clawed frog (xenopus laevis). the primary structure of an sp-like peptide was established as: lys-pro-arg-pro-asp-gln-phe-tyr-gly-leu-met.nh(2), which is identical to the previously characterized peptide, bufokinin isolated from the toad bufo marinus. the primary structure of an nka-related peptide was established as thr-leu-thr-thr ... | 2002 | 12220734 |
| properties of the vertebrate skeletal muscle tubular system as a sealed compartment. | confocal imaging of impermeant fluorescent dyes trapped in the tubular (t-) system of skeletal muscle fibres of rat and cane toad was used to examine changes in the morphology of the t-system upon mechanical skinning, the time course of dye loss from the sealed t-system in mechanically skinned fibres and the influence of rapid application and removal of glycerol on the morphology of the sealed t-system. in contrast to intact fibres, which have a t-system open to the outside, the sealed t-system ... | 2002 | 12421583 |
| effects of meal size, meal type, body temperature, and body size on the specific dynamic action of the marine toad, bufo marinus. | specific dynamic action (sda), the accumulated energy expended on all physiological processes associated with meal digestion, is strongly influenced by features of both the meal and the organism. we assessed the effects of meal size, meal type, body temperature, and body size on the postprandial metabolic response and calculated sda of the marine toad, bufo marinus. peak postprandial rates of o(2) consumption (.v(o2)) and co(2) production (.v(co2)) and sda increased with meal size (5%-20% of bod ... | 2002 | 12601612 |
| toad atrial natriuretic peptide: cdna cloning and functional analysis in isolated perfused kidneys. | a complementary dna (cdna) encoding bufo marinus (toad) preproatrial natriuretic peptide (preproanp) was isolated by reverse-transcription polymerase chain reaction. sequence analysis of toad preproanp cdna revealed an open reading frame of 150 amino acid residues, which shared 72% and 66% identity with rana catesbeiana and xenopus laevis preproanp, respectively. the deduced amino acid sequence of toad anp that corresponded to anp 1-24 of r. catesbeiana and rana ridibunda was identical, but it d ... | 2002 | 12601618 |
| lateralisation of predator avoidance responses in three species of toads. | lateralisation of responses to presentation of a simulated predator was investigated in three species of toads: two european species (the common toad, bufo bufo, and the green toad, bufo viridis) and one species introduced to australia from south america, the cane toad bufo marinus . first a simulated snake was presented moving rapidly towards the toad in the frontal field of vision and the toad's escape responses, including jumps to the right and to the left, were recorded. no significant bias ... | 2002 | 15513195 |
| [the tongue mast cells of bufo marinus l. toad: characterization of glycoconjugates with conventional and lectin methods]. | mast cell populations in mammals have been recognized as morphologically and functionally heterogeneous. in situ characterization of these cell type carbohydrates with conventional histochemical techniques and with lectin histochemistry has not been afforded in amphibian species. different conventional staining methods for complex carbohydrates and 18 different, biotin or peroxidase conjugated, lectins were used in paraffin embedded rossman fluid-fixed sections of mid-central region of the toad ... | 2002 | 12658867 |
| temperature effects on spectral properties of red and green rods in toad retina. | temperature effects on spectral properties of the two types of rod photoreceptors in toad retina, "red" and "green" rods, were studied in the range 0-38 degrees c. absorbance spectra of the visual pigments were recorded by single-cell microspectrophotometry (msp) and spectral sensitivities of red rods were measured by electroretinogram (erg) recording across the isolated retina. the red-rod visual pigment is a usual rhodopsin (lambda(max) = 503.6 nm and 502.3 nm at room temperature (21degrees c) ... | 2002 | 12688672 |
| isolation and characterization of cardiotonic steroid conjugates from the skin of bufo marinus (l.) schneider. | 2002 | 120230 | |
| tubular system volume changes in twitch fibres from toad and rat skeletal muscle assessed by confocal microscopy. | the volume of the extracellular compartment (tubular system) within intact muscle fibres from cane toad and rat was measured under various conditions using confocal microscopy. under physiological conditions at rest, the fractional volume of the tubular system (t-sys(vol)) was 1.38 +/- 0.09 % (n = 17), 1.41 +/- 0.09 % (n = 12) and 0.83 +/- 0.07 % (n = 12) of the total fibre volume in the twitch fibres from toad iliofibularis muscle, rat extensor digitorum longus muscle and rat soleus muscle, res ... | 2002 | 11790823 |
| structure-activity studies of bufokinin, substance p and their c-terminal fragments at bufokinin receptors in the small intestine of the cane toad, bufo marinus. | bufokinin is a substance p-related tachykinin peptide with potent spasmogenic actions, isolated from the intestine of the cane toad, bufo marinus. bufokinin acts via a tachykinin receptor with similarities to the mammalian nk(1) receptor. in this structure-activity study of bufokinin, substance p (sp) and their c-terminal fragments, we have used isolated segments and homogenates of toad small intestine to compare the contractile potencies and abilities to compete for the binding of [125i]-bolton ... | 2002 | 11841796 |
| purification, characterization, and biological activity of a substance p-related peptide from the gut of the australian lungfish, neoceratodus forsteri. | a peptide with mammalian substance p (sp)-like immunoreactivity was isolated from an extract of the spiral intestine of the australian lungfish, neoceratodus forsteri. the primary structure of this peptide was established as lys-pro-arg-pro-asp-glu-phe-tyr-gly-leu-met . nh2, showing 64% identity with mammalian sp. in isolated preparations of lungfish foregut circular muscle, lungfish sp produced a slow, long-lasting tonic contraction, with a pd2 value of 8.19. lungfish midgut circular muscle pre ... | 2002 | 11825039 |
| comparison of isometric contractile properties in hindlimb extensor muscles of the frogs rana pipiens and bufo marinus: functional correlations with differences in hopping performance. | the leopard frog (rana pipiens) is an excellent jumper that can reach high take-off velocities and accelerations. it is diurnal, using long, explosive jumps to capture prey and escape predators. the marine toad (bufo marinus) is a cryptic, nocturnal toad, typically using short, slow hops, or sometimes walking, to patrol its feeding area. typical of frogs with these different locomotor styles, rana has relatively long hindlimbs and large (by mass) hindlimb extensor muscles compared to bufo. we st ... | 2002 | 11835367 |
| an endocrinological update in toads: disparity between the cardiovascular effects of two angiotensin ii analogs. | this study was undertaken to test the hypothesis that, in toads, the pressor effects of angiotensin ii (ang ii) are partly due to the secondary effects of catecholamines. in bufo marinus, blood pressure responses to bullfrog ([val(5)]) ang ii administration were measured in animals pretreated (experimental group) and not pretreated (control group) with phentolamine, an alpha-adrenergic antagonist. at 1, 2, and 4 min following ang ii administration (50 ngkg(-1)), mean arterial pressure (map) of t ... | 2003 | 12765652 |
| a novel signalling pathway originating in mitochondria modulates rat skeletal muscle membrane excitability. | single skeletal muscle fibres from rat and cane toad were mechanically skinned and stimulated either electrically by initiating action potentials in the sealed transverse (t-) tubular system or by ion substitution causing depolarisation of the t-system to pre-determined levels. depression of mitochondrial atp-producing function with three diverse mitochondrial function antagonists (azide: 1-10 mm; oligomycin 1 microg ml-1 and carbonyl cyanide 4-trifluoromethoxyphenylhydrazone (fccp) 1 microm), u ... | 2003 | 12611917 |
| toad venom poisoning: resemblance to digoxin toxicity and therapeutic implications. | a healthy man developed gastrointestinal symptoms after ingesting purported aphrodisiac pills. he had severe unrelenting bradycardia, hyperkalaemia, and acidosis. he rapidly developed severe life threatening cardiac arrhythmias and died after a few hours. he was found to have positive serum digoxin concentrations, although he was not taking digoxin. toad venom poisoning is similar to digitalis toxicity and carries a high mortality. cardiac glycoside poisoning can occur from ingestion of various ... | 2003 | 12639891 |
| the effect of saccharides on the post-thaw recovery of cane toad (bufo marinus) spermatozoa. | the effect of monosaccharides (glucose, fructose) and disaccharides (maltose, sucrose, trehalose) as diluents, in cryoprotective additives containing 15% (v/v) dmso or glycerol as cryoprotectants, were investigated on the recovery of sperm motility after cryopreservation of cane toad (bufo marinus) spermatoazoa at low (approximately 5 degrees c/min(-1)) and high cooling rates (approximately 35 degrees c/min(-1)). the results show that: 1. recovery of percentage motility was higher with slow cool ... | 2003 | 12050780 |
| cardiovascular responses to hypoxia and anaemia in the toad bufo marinus. | amphibians exhibit cardiorespiratory responses to hypoxia and, although several oxygen-sensitive chemoreceptor sites have been identified, the specific oxygen stimulus that triggers these responses remains controversial. this study investigates whether the cardiovascular response to oxygen shortage correlates with decreased oxygen partial pressure of arterial blood (pa(o(2))) or reduced oxygen concentration ([o(2)]) in toads. toads, equipped with blood flow probes and an arterial catheter, were ... | 2003 | 12547940 |
| schwann cell dynamics with respect to newly formed motor-nerve terminal branches on mature (bufo marinus) muscle fibers. | a study has been made of the formation of synaptic terminals from long processes formed at the end of motor nerve branches of endplates in mature amphibian (bufo marinus) muscle. injection of fluorescent dyes into individual motor axons showed the full extent of their branches at single endplates. synaptic vesicle clusters at these branches were identified with styryl dyes. some terminal branches consisted of well separated varicosities, each possessing a cluster of functioning synaptic vesicles ... | 2003 | 14724381 |
| resting respiratory behavior in minimally instrumented toads--effects of very long apneas on blood gases and ph. | resting respiratory behavior of bufo marinus in minimally instrumented toads is described for a period of 24 hours in which the animals are left undisturbed. torpor-related long apneas are described and their implications for blood gas levels are investigated. results show that the resting ventilation rate of bufo marinus is much lower than that reported so far. levels of arterial oxygen, carbon dioxide, and ph are monitored during artificial long apneas induced by anesthesia. the toads showed a ... | 2003 | 12914413 |
| ventilatory behaviors of the toad bufo marinus revealed by coherence analysis. | breathing in amphibians is a remarkably complex behavior consisting of irregular breaths that may be taken singly or in bouts that are used to deflate and inflate the lungs. the valves at the two outlets of the buccal cavity (nares and glottis) need to be finely controlled throughout the bout for the expression of these complex respiratory behaviors. in this study, we use a technique based on the calculation of the coherence spectra between respiratory variables (buccal pressure; narial airflow; ... | 2003 | 12914412 |
| effects of inhibition gastric acid secretion on arterial acid-base status during digestion in the toad bufo marinus. | digestion affects acid-base status, because the net transfer of hcl from the blood to the stomach lumen leads to an increase in hco3(-) levels in both extra- and intracellular compartments. the increase in plasma [hco3(-)], the alkaline tide, is particularly pronounced in amphibians and reptiles, but is not associated with an increased arterial ph, because of a concomitant rise in arterial pco2 caused by a relative hypoventilation. in this study, we investigate whether the postprandial increase ... | 2003 | 12829050 |
| role of environmental pollutants on immune functions, parasitic infections and limb malformations in marine toads and whistling frogs from bermuda. | soil, water, and amphibian tissues collected between 1995 and 1999 from 15 study sites in bermuda were analysed for pesticides and heavy metals. the most abundant pesticide residue in soil was p,p'-dichlorodiphenyldichloroethylene (dde) which was found at all sites in concentrations ranging from 0.003 to 4.023 p.p.m. no pesticide residues were found in water. dde was also recovered from the livers and fat bodies of marine toads (bufo marinus) and whistling frogs (eleutherodactylus johnstonei). a ... | 2003 | 12745335 |
| early effects of metabolic inhibition on intracellular ca2+ in toad pacemaker cells: involvement of ca2+ stores. | the early effects of metabolic inhibition on intracellular ca(2+) concentration ([ca(2+)](i)), ca(2+) current, and sarcoplasmic reticulum (sr) ca(2+) content were studied in single pacemaker cells from the sinus venosus of the cane toad. the amplitude of the spontaneous elevations of systolic [ca(2+)](i) (ca(2+) transients) was reduced after 5-min exposure to 2 mm nacn from 338 +/- 30 to 189 +/- 37 nm (p < 0.005, n = 9), and the spontaneous firing rate was reduced from 27 +/- 2 to 12 +/- 4 beats ... | 2003 | 12595299 |
| metabolic costs induced by lactate in the toad bufo marinus: new mechanism behind oxygen debt? | the mechanism of an increase in metabolic rate induced by lactate was investigated in the toad bufo marinus. oxygen consumption (vo(2)) was analyzed in fully aerobic animals under hypoxic conditions (7% o(2) in air), accompanied by measurements of catecholamines in the plasma, and was measured in isolated hepatocytes in vitro under normoxia by using specific inhibitors of lactate proton symport [alpha-cyano-4-hydroxycinnamate (chc)] and sodium proton exchange (eipa). the rise in metabolic rate i ... | 2003 | 12433869 |
| atp modulates intracellular ca2+ and firing rate through a p2y1 purinoceptor in cane toad pacemaker cells. | the effect of extracellular atp (10-100 microm) on intracellular ca2+ concentration ([ca2+]i) and firing rate has been studied in single pacemaker cells isolated from the sinus venosus of cane toads. in spontaneously firing cells, atp initially increased peak [ca2+]i by 43 +/- 5 %, increased diastolic [ca2+]i by 20 + 3 % and increased the firing rate by 58 +/- 8 %. these early effects were followed by a late phase in which both the peak [ca2+]i and the firing rate declined. adenosine, and utp (r ... | 2003 | 12949218 |
| modulation of breathing by phasic pulmonary stretch receptor feedback in an amphibian, bufo marinus. | this study examined the role of phasic pulmonary stretch receptor (psr) feedback in ventilatory control, breath clustering and breath timing in decerebrate, paralysed and artificially-ventilated cane toads (bufo marinus) under conditions designed to minimise tonic psr feedback. fictive breathing was recorded as trigeminal motor output to the buccal musculature. artificial tidal ventilation, with hypercarbic gas mixtures, was either continuous or activated by the fictive breaths and was manipulat ... | 2004 | 15450478 |