| effect of salt depletion on sodium concentration in serum and urine of bufo chilensis. evidences for increased levels of neurohypophysial principles in their plasma. | salt-depleted toads bufo chilensis were compared with animals maintained in nacl solution and a control group with respect to na+ content in serum and urine. plasma hydro-osmotic activity of the animals was measured by increased water transfer across the isolated urinary bladder of the frog (caudiverbera caudiverbera). sodium in serum is not affected by pre-adaptation in distilled water. urine na+ is markedly reduced. plasma from depleted animals increases water transfer across the isolated urin ... | 2010 | 2881665 |
| presence of ca2+-dependent k+ channels in chemosensory cilia support a role in odor transduction. | olfactory receptor neurons (orns) respond to odorants with changes in the action potential firing rate. excitatory responses, consisting of firing increases, are mediated by a cyclic amp cascade that leads to the activation of cationic nonselective cyclic nucleotide-gated (cng) channels and ca2+-dependent cl- (clca) channels. this process takes place in the olfactory cilia, where all protein components of this cascade are confined. orns from various vertebrate species have also been shown to gen ... | 2003 | 12801890 |
| membrane current of retinal rods of caudiverbera caudiverbera (amphibia: leptodactylidae): dark noise, spectral and absolute light sensitivity. | we investigated the photocurrents from isolated rods of the south american anuran, caudiverbera caudiverbera. rod outer segments were on average 66.4 +/- 11.2 microm (mean +/- s.d., n = 104) in length and 6.6 +/- 0.9 microm (mean +/- s.d.) in diameter: 40 +/- 22 photoisomerizations (mean +/- s.d., range 10-99, n = 16) were required for eliciting a half-saturating photocurrent response. the time-to-peak was 911 +/- 217 ms (mean +/- s.d., n = 14, 20 degrees c) in the linear range of the response a ... | 2001 | 11829312 |
| ionic components of the electrical response of chromaffin cells from the toad (caudiverbera caudiverbera) adrenal gland. | 1. ultra fine tip microelectrodes (300 mohm) were used to study the electrical properties of the chromaffin cell membrane in situ in the intact toad adrenal gland. 2. in the presence of physiologic [k+]o (2 mm) the resting membrane potential (vm) was -53 +/- 3.2 mv. vm depended on [k+]o as predicted by the constant field equation with pna/pk of 0.16. 3. a small fraction (20%) of the impaled cells exhibited spontaneous electrical activity, though in all the cells examined, the injection of depola ... | 1993 | 7900970 |
| [helminthological fauna of chilean anura]. | in this paper a list of the endoparasites described for the chilean frogs and toads is presented. also it is indicated the locality of the hosts, prevalence and intensity of the infection. nine species of parasites have been described; three trematodes: gorgoderina chilensis in rhinoderma darwinii, gorgoderina valdiviensis in caudiverbera caudiverbera, and rudolphitrema chilensis in eusophus roseus; two cestodes: ophiotaenia noei in c. caudiverbera, and baerietta chilensis in batrachyla taeniata ... | 1994 | 7654293 |
| partial characterization of pepsins and gastricsins and their zymogens from human and toad gastric mucosae. | 1. three zymogens have been isolated from human gastric mucosae and two from the stomachs of the toad caudiverbera caudiverbera. 2. human zymogens i and iii were immunologically related and cross-reacted with antisera prepared against porcine pepsinogen. the third, (ii), showed no cross-reactivity. 3. human zymogens i and iii and toad zymogen zii gave rise to two human pepsins and to a pepsin-like enzyme, respectively. 4. human zymogen ii (gastricsinogen) and toad zymogen zi gave rise to human g ... | 1978 | 122571 |
| substance p-like immunoreactivity in sympathetic ganglion from toad. | substance p-like immunoreactivity cellular in toad sympathetic ganglia was studied in normal and capsaicin-treated ganglia. in the eighth sympathetic ganglion substance p-like immunoreactive are found in mast cells and sif cells. the effect of substance p (0.001-0.003 mm) caused increase of compound action potential during tetanical stimulation (50 hz by 40 sec.) and post-tetanic potentiation (0.1 hz). our results show that substance p facilitates synaptic transmission in the sympathetic ganglia ... | 1989 | 2476215 |
| effects of 7-o-demethylisothalicberine, a bisbenzylisoquinoline alkaloid of berberis chilensis, on electrical activity of frog cardiac pacemaker cells. | 1. in spontaneously beating preparations of sinus venosus of the chilean frog caudiverbera caudiverbera, the electrophysiological effects of 7-o-demethylisothalicberine (7-o-di) on transitional pacemaker cells were investigated. 2. 7-o-di in concentration 1 x 10(-4) m blocked the action potential of transitional cells. this blockade was preceded by subthreshold oscillations and depolarization of membrane potential. 3. lower concentration of the drug to induce complete blockade (5 x 10(-5) m), al ... | 1989 | 2606331 |
| catecholamine secretion from adrenal chromaffin cells of the toad (caudiverbera caudiverbera): effect of monensin. | 1. stimulus-secretion coupling studies were carried out on adrenal chromaffin tissue from the toad. catecholamine (ca) secretion was generated in response to acetylcholine (ach) or high k+. 2. the response to ach was found to be dependent on the presence of external ca2+. the secretion induced by ach or high k+ was inhibited by the ca-channel blockers cocl2 and nifedipine. 3. the specific na+/h+ ionophore, monensin, induced a strong secretory response only if na+ was present in the ringer. monen ... | 1992 | 1354094 |
| is sodium necessary for stimulus-secretion coupling in toad (caudiverbera caudiverbera) adrenal chromaffin cells? | 1. chromaffin cells of the toad were used to investigate the effects of total replacement of extracellular na+ by monovalent cations or sucrose on secretion of catecholamine (ca). 2. k+, rb+ or cs+ in place of na+ produced an immediate secretory response, which are dependent on extracellular ca2+ and it was blocked by co2+. li+ or choline+ did not affect basal secretion. 3. isosmotic replacement of na+ by sucrose caused ca secretion even in the absence of external ca2+ or in the presence of ca-c ... | 1992 | 1355040 |
| effects of bekanamycin and dibekacin on the electrical activity of cardiac pacemaker cells. | in spontaneously beating sinus venosus of the frog caudiverbera caudiverbera the effects of bekanamycin and dibekacin, two aminoglycoside antibiotics, on action potentials of cardiac primary pacemaker cells were studied by intracellular recording. bekanamycin and dibekacin induced a concentration-dependent decrease of the amplitude, overshoot and the rate of rise of the action potential. both also flattened the slow diastolic depolarization leading to a marked decrease in beat rate. at the highe ... | 1993 | 8118157 |
| properties of whole cell currents in isolated olfactory neurons from the chilean toad caudiverbera caudiverbera. | isolated olfactory neurons from the chilean toad caudiverbera caudiverbera were found to possess a same set of currents. outward currents, made of a delayed rectifier and a ca(2+)-dependent component, were blocked by replacing k+ by cs+ in the patch pipette, in the presence of millimolar concentrations of tetraethylammonium and 4-aminopyridine in the external solution. inward currents were made of a transient and a maintained component. the transient was abolished in the absence of external na+ ... | 1993 | 8333496 |
| pentachlorophenol (pcp) inhibits ion transport in the isolated toad cornea. | 1. active chloride transport from the stroma to the epithelial surface (tear side) accounts for 80% of the amphibian cornea short-circuit current (scc). 2. the effect of pentachlorophenol (pcp, a wood preservative) on the bioelectric parameters of the toad caudiverbera caudiverbera isolated cornea was studied. 3. pcp applied to the epithelial surface in the concentration range 0.3-4.3 microm caused a dose-dependent inhibition of the pd and of the scc in 7 corneas. this inhibition was irreversibl ... | 1993 | 8224741 |
| calcium channel blockers apparently decrease noradrenaline release from nerve-skin terminals in caudiverbera caudiverbera. | 1. the effects of three calcium channel blockers, verapamil, diltiazem and nifedipine were examined on the response of the skin neuroepithelial synapse of the toad caudiverbera caudiverbera to electrical stimulation. 2. the stimulus induced a significant rise in potential difference (pd) and short-circuit current (scc). the three calcium antagonists reduced the responses in a dose-dependent manner. the greatest reduction was induced by verapamil followed by diltiazem and nifedipine. 3. amiloride ... | 1993 | 8224750 |
| fructose-1,6-bisphosphatase in stage vi frog oocytes: evidence for an active enzyme in vivo. | the characterization of fructose-1,6-bisphosphatase in stage vi oocytes from the frog caudiverbera caudiverbera, as well as the in vivo activity, is reported. the enzyme has a subunit molecular weight of approximately 43,500, has an apparent km value of 17 microm for fructose-1,6-bisp, and is inhibited by substrate concentrations beyond 100 microm. amp and fructose-2,6-bisp are strong inhibitors of oocyte fructose-1,6-bisphosphatase activity with ki values of 9 and 2 microm respectively. inhibit ... | 1995 | 7840666 |
| a ciliary k+ conductance sensitive to charibdotoxin underlies inhibitory responses in toad olfactory receptor neurons. | in olfactory neurons from caudiverbera caudiverbera, a mixture of putrid odorants trigger an inhibitory, k(+)-selective current and a hyperpolarizing receptor potential. the current-voltage relation resembles that of a ca(2+)-activated k+ conductance; their amplitude depends on extracellular ca2+. 10 nm charibdotoxin, a blocker of k(+)-selective channels, including ca(2+)-activated ones, reversibly abolished inhibitory currents and receptor potentials. focal stimulation demonstrates that the und ... | 1995 | 7531652 |
| diazepam decreases the response to the electrical stimulation of the nerve-skin preparation of the toad caudiverbera caudiverbera. | 1. the effect of diazepam was examined in the nerve skin preparation of the toad caudiverbera caudiverbera. 2. nerve stimulation was followed immediately by a transient increase in short-circuit current (scc) and in the potential difference (pd), which consisted of a rapid and then a slow component. 3. diazepam concentrations from 5.0 x 10(-5)m to 5.1 x 10(-4)m caused a dose-dependent block of both components to a 30% of their control values and also reduced the stimulatory responses to noradren ... | 1995 | 8690254 |
| toxic action of the herbicide 2,4-d on the neuroepithelial synapse and on the nonstimulated skin of the frog caudiverbera caudiverbera. | | 1999 | 10227836 |
| cytoarchitecture of caudiverbera caudiverbera stage vi oocytes: a light and electron microscope study. | the general characteristics and salient features of the full-grown stage vi caudiverbera caudiverbera oocyte at the light and electron microscopy level are described. the oocyte is a huge cell with radial symmetry and distinct polarity. a black animal hemisphere, rich in pigment granules and containing the nucleus, is clearly distinguished from the unpigmented white-yellowish vegetal hemisphere. the cell is surrounded by a highly invaginated plasma membrane, with numerous microvilli. the cortex ... | 1999 | 10350129 |
| the toxicity of exposure to the organochlorine, dieldrin, at a sympathetic junction and on the skin of the frog, caudiverbera caudiverbera. | the effects of the organochlorine, dieldrin, were tested on a noradrenergic synapse of the frog, caudiverbera caudiverbera. nerve stimulation induced a transient increase in short circuit current (scc) and in the potential difference (pd), which consisted of a rapid and then a slow component. dieldrin in the concentration range 0.01-1.0 mm caused a concentration-dependent block of both components to 32% of their control values, which was partially reversed by washout. in some experiments, this b ... | 2002 | 12507253 |
| digestive plasticity in tadpoles of the chilean giant frog (caudiverbera caudiverbera): factorial effects of diet and temperature. | anuran metamorphosis is one of the most spectacular processes in nature. metamorphosis entails morphological transformations and extensive changes in feeding habits, such as transforming from an herbivore to a carnivore. this phenomenon is especially sensitive to environmental cues. we studied the phenotypic plasticity of intestinal morphology and enzyme activity in tadpoles of the chilean giant frog caudiverbera caudiverbera. we tested the effects of diet and temperature using a factorial desig ... | 2006 | 16927238 |
| energy requirements of odor transduction in the chemosensory cilia of olfactory sensory neurons rely on oxidative phosphorylation and glycolytic processing of extracellular glucose. | the mechanisms that power the physiological events occurring in cilia, flagella, and microvilli are of fundamental importance for the functions of these important and ubicuous organelles. the olfactory epithelium is mostly populated by ciliated olfactory sensory neurons (osns) and surrounding sustentacular cells (scs) with apical microvilli. the only osn dendrite extends to the surface forming a knob projecting several chemosensory cilia of ∼50 × 0.2 μm, devoid of inner membranes embedded in a m ... | 2017 | 28500222 |
| odor suppression of voltage-gated currents contributes to the odor-induced response in olfactory neurons. | olfactory chemotransduction involves a signaling cascade. in addition to triggering transduction, odors suppress ion conductances. by stimulating with brief odorant pulses, we observed a current associated with odor-induced suppression of voltage-gated conductances and studied its time dependence. we characterized this suppression current in isolated caudiverbera caudiverbera olfactory neurons. all four voltage-gated currents are suppressed by odor pulses in almost every neuron, and suppression ... | 1999 | 10600760 |
| nitric oxide activates a potassium current in olfactory receptor neurons from caudiverbera caudiverbera and xenopus laevis. | the putative role of nitric oxide (no) in the physiology of olfactory receptor neurons (orns) is controversial. here we report that pulses of no caused an outward current in voltage-clamped isolated olfactory neurons. the i-v relation of this effect, its sensitivity to charybdotoxin and its dependence on external potassium suggest that no activates a k(+)-conductance. as blockers of soluble guanylyl cyclases failed to affect the current, we conclude that no opens k(+)-channels in a cgmp-independ ... | 1999 | 10434016 |
| inhibitory k+ current activated by odorants in toad olfactory neurons. | odorant responses of isolated olfactory neurons from the toad caudiverbera caudiverbera were monitored by using patch-clamp techniques. depending on the stimulus, the same neuron responded with an increase or a decrease in action potential firing. odorants that activate the camp cascade in olfactory cilia increased electrical activity, caused membrane depolarization, and triggered inward currents. in contrast, odorants that do not activate the camp cascade inhibited electrical activity, produced ... | 1994 | 7991632 |
| some morphological, cytological and histochemical characteristics of eighth sympathetic ganglia from caudiverbera caudiverbera. | | 1981 | 7326704 |
| electrophysiological effects of verapamil on primary and transitional pacemaker cells of the frog heart. | 1. in spontaneously beating preparations of sinus venosus of the frog caudiverbera caudiverbera the electro-physiologic effects of verapamil on action potential parameters of both primary and transitional pacemaker cells were investigated. 2. verapamil in concentrations ranging from 5 x 10(-8)m to 2 x 10(-6)m slowed the sinus rate and blocked impulse initiation. action potential blockade was accompanied by oscillations of membrane potential and depolarization. 3. during blockade of primary pacem ... | 1988 | 3417105 |
| use of selective toxins to separate surface and tubular sodium currents in frog skeletal muscle fibers. | the interaction between toxin gamma from the venom of the scorpion tityus serrulatus and sodium channels in skeletal muscle membranes from the frog caudiverbera caudiverbera was studied. sodium current from cut sartorius muscle fibers is a complex signal in which early and late components are difficult to separate. external application of tityus gamma toxin initially blocked the early component in a voltage-dependent manner. longer exposure to the toxin induced a complete blockade of the two com ... | 1988 | 2451210 |
| electrophysiological effects of bupivacaine on transitional pacemaker cells of the frog heart. | the effects of bupivacaine, a long-acting local anesthetic, were studied on action potentials of spontaneously beating sinus venosus of the frog caudiverbera caudiverbera. the study was accomplished by recording transmembrane potentials of pacemaker transitional cells. action potentials of these cells are known to have both a fast and a slow ionic component. bupivacaine (1 x 10(-5) m to 1 x 10(-4) m) caused a reversible negative chronotropic effect accompanied by decrease of diastolic depolariza ... | 1987 | 2821942 |
| electrophysiological characteristics of cardiac pacemaker cells of the frog caudiverbera caudiverbera. | 1. the cardiac pacemaker cells of the frog caudiverbera caudiverbera are centrally located in the sinus venosus. these cells are rounded, smaller than contractile fibres and have large nuclei. 2. intracellular recording confirmed the existence of primary and transitional pacemaker cells. 3. action potentials from primary cells were resistant to blockade by tetrodotoxin (ttx), but were abolished by verapamil suggesting that their bioelectric activity is dependent on a slow inward current. 4. tran ... | 1987 | 2887351 |
| electrophysiological effects of 4-aminoquinoline on frog atrial contractile fibres. | the effects of 4-aminoquinoline (4-aq), a drug structurally related to 4-aminopyridine, were studied on atrial contractile fibres from the amphibian caudiverbera caudiverbera by means of intracellular electrodes. in concentrations that did not change resting potential, 4-aq (0.25-1.5 mm) reduced upstroke velocity, action potential amplitude (apa) and overshoot in a dose-dependent manner. 4-aq also prolonged action potential duration (apd) and the fibre effective refractory period (erp), making t ... | 1984 | 6466010 |
| effects of 4-aminoquinoline on action potentials of the frog sinus venosus. | the electrophysiological effects of 4-aminoquinoline (4-aq), a drug structurally related to 4-aminopyridine, were studied on the sinus venosus of the frog caudiverbera caudiverbera with standard microelectrode techniques. 4-aq in concentrations (0.01-1.5 mm) that did not modify membrane resting potential, reversibly depressed pacemaker activity and the rate of diastolic depolarization. these effects were not prevented by atropine. 4-aq also reduced maximum diastolic potential, whereas action pot ... | 1982 | 7181584 |