Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
???displayArticle.abstract???
Resting potential (r.p.) and muscarinic response mechanisms were studied in Xenopus laevis oocytes using the voltage-clamp technique. Insertion of micro-electrodes into the oocyte produced a 'shunt' membrane conductance which partially sealed after a few minutes. The oocyte resting potential (measured with a single intracellular electrode) ranged from -40 to -60 mV. Ouabain and low K+ solution depolarized both follicles and denuded oocytes. The electrogenic Na+-K+ pump was more active in the latter. In the presence of ouabain, the r.p. agreed with the constant field theory. alpha (PNa+/PK+) was 0.12 in follicles and 0.24 in denuded oocytes. beta (PCl-/PK+) was 0.4 in both. At [Na+]o lower than 70 mM, the r.p. deviated considerably from the constant field predictions. The relatively large value of alpha indicated the major role of Na+ in oocyte r.p. determination. The oocyte muscarinic response was separated into four distinct components: the fast depolarizing Cl- current, 'D1'; the slow depolarizing Cl- current, 'D2'; the slow hyperpolarizing K+ current, 'H'; and the large membrane Cl- current fluctuation, 'F'. The H response reversal potential showed a Nernst relationship to [K+] and was selectively blocked by intracellular injection of tetraethylammonium (TEA). The D1 and D2 reversal potential showed a Nernst relationship to [Cl-]. In Ca2+-deficient, EGTA-containing medium, D2 and F were abolished and D1 and H were reduced. Verapamil inhibited all responses. Increasing [Ca2+]o caused a significant increase in D1, D2 and F response amplitudes. Intracellular injection of 0.6-10 pmol guanosine 3',5'-cyclic monophosphate, induced a large outward K+ current, similar to the muscarinic H response.
Baud,
Sodium channels induced by depolarization of the Xenopus laevis oocyte.
1982, Pubmed,
Xenbase
Baud,
Sodium channels induced by depolarization of the Xenopus laevis oocyte.
1982,
Pubmed
,
Xenbase Baulieu,
Steroid-induced meiotic division in Xenopus laevis oocytes: surface and calcium.
1978,
Pubmed
,
Xenbase Beam,
Cyclic nucleotides, protein phosphorylation and synaptic function.
1976,
Pubmed Bellé,
Free calcium in full grown Xenopus laevis oocyte following treatment with ionophore A 23187 or progesterone.
1977,
Pubmed
,
Xenbase Brooker,
Dissociation of cyclic GMP from the negative inotropic action of carbachol in guinea pig atria.
1977,
Pubmed Busis,
Synaptic potentials in sympathetic ganglia: are they mediated by cyclic nucleotides?
1978,
Pubmed Dascal,
Cyclic GMP mimics the muscarinic response in Xenopus oocytes: identity of ionic mechanisms.
1982,
Pubmed
,
Xenbase Dascal,
Types of muscarinic response in Xenopus oocytes.
1980,
Pubmed
,
Xenbase Dick,
The activities and concentrations of sodium and potassium in toad oocytes.
1969,
Pubmed Dumont,
Oogenesis in Xenopus laevis (Daudin). V. Relationships between developing oocytes and their investing follicular tissues.
1978,
Pubmed
,
Xenbase Dumont,
Oogenesis in Xenopus laevis (Daudin). I. Stages of oocyte development in laboratory maintained animals.
1972,
Pubmed
,
Xenbase Dun,
Muscarinic and cGMP induced membrane potential changes: differences in electrogenic mechanisms.
1978,
Pubmed Eppig,
Amino acid pools in developing oocytes of Xenopus laevis.
1972,
Pubmed
,
Xenbase Fleckenstein,
Specific pharmacology of calcium in myocardium, cardiac pacemakers, and vascular smooth muscle.
1977,
Pubmed Fleming,
Are acetylcholine-induced increases in 42K efflux mediated by intracellular cyclic GMP in turtle cardiac pace-maker tissue?
1981,
Pubmed Frank,
Potassium exchange in the whole cell, cytoplasm, and nucleus of amphibian oocytes.
1980,
Pubmed Frey,
A comparison of cyclic guanosine 3':5'-monophosphate and muscarinic excitatory responses in the superior cervical ganglion of the rat.
1981,
Pubmed Gallagher,
Cyclic nucleotides injected intracellularly into rat superior cervical ganglion cells.
1977,
Pubmed Greengard,
Possible role for cyclic nucleotides and phosphorylated membrane proteins in postsynaptic actions of neurotransmitters.
1976,
Pubmed Greengard,
Phosphorylated proteins as physiological effectors.
1978,
Pubmed HAGIWARA,
Voltage-current relations in nerve cell membrane of Onchidium verruculatum.
1959,
Pubmed Hashiguchi,
Does cyclic GMP mediate the slow excitatory synaptic potential in sympathetic ganglia?
1978,
Pubmed Hermann,
Effects of tetraethylammonium on potassium currents in a molluscan neurons.
1981,
Pubmed Hille,
The selective inhibition of delayed potassium currents in nerve by tetraethylammonium ion.
1967,
Pubmed HODGKIN,
The effect of sodium ions on the electrical activity of giant axon of the squid.
1949,
Pubmed HODGKIN,
The influence of potassium and chloride ions on the membrane potential of single muscle fibres.
1959,
Pubmed Imaizumi,
The effect of tetraethylammonium chloride on potassium permeability in the smooth muscle cell membrane of canine trachea.
1981,
Pubmed Kusano,
Acetylcholine receptors in the oocyte membrane.
,
Pubmed
,
Xenbase Kusano,
Cholinergic and catecholaminergic receptors in the Xenopus oocyte membrane.
1982,
Pubmed
,
Xenbase Lee,
pH changes associated with meiotic maturation in oocytes of Xenopus laevis.
1981,
Pubmed
,
Xenbase Lotan,
Adenosine-induced slow ionic currents in the Xenopus oocyte.
1982,
Pubmed
,
Xenbase MAENO,
Electrical characteristics and activation potential of Bufo eggs.
1959,
Pubmed Masui,
Oocyte maturation.
1979,
Pubmed Masui,
Relative roles of the pituitary, follicle cells, and progesterone in the induction of oocyte maturation in Rana pipiens.
1967,
Pubmed McAfee,
Adenosine 3',5'-monophosphate: electrophysiological evidence for a role in synaptic transmission.
1972,
Pubmed Merriam,
Progesterone-induced maturational events in oocytes of Xenopus laevis. I. Continuous necessity for diffusible calcium and magnesium.
1971,
Pubmed
,
Xenbase Miledi,
A calcium-dependent transient outward current in Xenopus laevis oocytes.
1982,
Pubmed
,
Xenbase Moreau,
[Early changes in the electric properties of the oocyte plasma membrane of Xenopus laevis during the reinitiation of meiosis induced by progesterone, para chloromercuribenzoate (PCMB) or the ionophore A 23187].
1976,
Pubmed
,
Xenbase Morrill,
An analysis of transport, exchange, and binding of sodium and potassium in isolated amphibian follicles and denuded oocytes.
1977,
Pubmed Nachshen,
The effects of some organic "calcium antagonists" on calcium influx in presynaptic nerve terminals.
1979,
Pubmed Nawrath,
Does cyclic GMP mediate the negative inotropic effect of acetylcholine in the heart?
1977,
Pubmed Nawrath,
Cyclic AMP and cyclic GMP may play opposing roles in influencing force of contraction in mammalian myocardium.
1976,
Pubmed O'Connor,
Calcium, potassium, and sodium exchange by full-grown and maturing Xenopus laevis oocytes.
1977,
Pubmed
,
Xenbase Poggioli,
Net calcium fluxes in rat parotid acinar cells: evidence for a hormone-sensitive calcium pool in or near the plasma membrane.
1982,
Pubmed Putney,
Stimulus-permeability coupling: role of calcium in the receptor regulation of membrane permeability.
1978,
Pubmed Richelson,
The molecular basis of neurotransmission at the muscarinic receptor.
1981,
Pubmed Robinson,
Electrical currents through full-grown and maturing Xenopus oocytes.
1979,
Pubmed
,
Xenbase Schultz,
The importance of calcium ions for the regulation of guanosine 3':5'-cyclic monophosphage levels.
1973,
Pubmed Stone,
Cyclic AMP and cyclic GMP may mediate opposite neuronal responses in the rat cerebral cortex.
1975,
Pubmed Thomas,
Electrogenic sodium pump in nerve and muscle cells.
1972,
Pubmed Trautwein,
The effect of intracellular cyclic nucleotides and calcium on the action potential and acetylcholine response of isolated cardiac cells.
1982,
Pubmed Tupper,
The ionic permeability of the amphibian oocyte in the presence or absence of external calcium.
1973,
Pubmed Vitto,
Maturation of Xenopus oocytes. I. Facilitation by ouabain.
1976,
Pubmed
,
Xenbase Wallace,
Protein incorporation by isolated amphibian oocytes. 3. Optimum incubation conditions.
1973,
Pubmed
,
Xenbase Wallace,
Maturation of Xenopus oocytes. II. Observations on membrane potential.
1977,
Pubmed
,
Xenbase Ziegler,
Regulation of the amphibian oocyte plasma membrane ion permeability by cytoplasmic factors during the first meiotic division.
1977,
Pubmed
