[Effects of allapinin on sodium currents in isolated neurons of the trigeminal ganglia and cardiomyocytes of rats]. / Vliianie allapinina na natrievye toki izolirovannykh neironov trigeminal'nykh gangliev i kardiomiotsitov krys.

Block of sodium currents by allapinin (diterpene alkaloid with strong antiarrhythmic properties) was investigated in isolated, voltage clamped rat trigeminal neurons and cultured neonatal rat single ventricular myocytes. Allapinin produces a decrease in sodium current amplitude without any changes in voltage dependent properties. Possible differences between the mechanisms of antiarrhythmic effect of diterpene alkaloids and classic antiarrhythmic agents have been analysed.

[Pentobarbital interaction with the GABA-activated ion channels of the neurons in the rat cerebellum]. / Vzaimodeistvie pentobarbitala s GAMK-aktiviruemymi ionnymi kanalami neironov mozzhechka krys.

GABA and barbiturate-activated currents of isolated single neurons in the rat cerebellum were studied by means of the concentration clamp, voltage clamp and intracellular perfusion methods. The dissociation constant (Kd) was 3 +/- 0.8.10(-5) M. Pentobarbital potentiated the GABA-induced conduction of isolated neurons. The dose-effect for GABA shifted along the abscissa axes. Optimal concentrations which potentiated the GABA effect were within 10(-6)-10(-4) M. The pentobarbital concentrations above 5.10(-4) M without GABA activated the Cl conductance. The short-time conductance during fast pentobarbital washing off was found to increase.

[Taurine-activated currents in isolated neurons of the rat cerebellum]. / Toki, aktiviruemye taurinom, v izolirovannykh neironakh mozzhechka krys.

Taurine-activated currents in isolated neurons of the rat cerebellum were studied by voltage and "concentration" clamp methods. They were transmitted by potassium and chloride ions. The dose-response curve with the dissociation constant 2 x 10(-3) mol/l was obtained. The cross-desensitization between taurine and GABA, but not between taurine and glycine was shown. These currents were also blocked by bicucullin and strychnine, but in a different manner.

[The effect of allapinine on the sodium currents of isolated trigeminal ganglion neurons and cardiomyocytes of rats]. / Vliianie allapinina na natrievye toki izolirovannykh neironov trigeminal'nogo gangliia i kardiomiotsitov krys.

Block of sodium currents by allapinine (diterpene alkaloid with strong antiarrhythmic properties) was investigated in isolated, voltage-clamped trigeminal neurons of a rat and single ventricular myocytes of a neonatal rat. Allapinine (in micromolar concentrations) produced a 70-90% decrease of the sodium current amplitude without any changes in voltage-dependent properties of INa in both neurons and cardiomyocytes. Allapinine also blocked the aconitine-modified sodium current. An increase of depolarization frequencies (0.5 to 5.0 Hz) produced no additional block of sodium currents in allapinine-bathed neurons and ventricular myocytes.

[Gaba-activated conductance of isolated neurons of rat cerebellum and sensory ganglia]. / GAMK-aktiviruemaia provodimost' izolirovannykh neironov mozzhechka i sensornykh gangliev krys.

Results of the study of GABA-activated ion currents on single isolated neurons of rat were obtained by means of voltage-clamp, intracellular perfusion and "concentration clamp" methods. The reversion potential of GABA-activated current corresponded to the equilibrium potential for Cl ions as it was determined by the Nernst equation. The dose-response relationship was activated by a single GABA molecule (Kd = 1.4.10(-4) mol/l). GABA-activated currents were blocked by bicuculline methoiodide and isocoryne.

[Izokorin--a new blockader of gamma-aminobutyric acid receptors in the mammalian nervous system]. / Izokorin--novyi blokator retseptorov gamma-aminomaslianoi kisloty v nervnoi sisteme mlekopitaiushchikh.

Experiments on isolated neurons of sensory ganglions of rats aimed to find physiologically active plant drugs were carried out by means of voltage-clamp, intracellular perfusion and "concentration-clamp" methods. Izokorin was shown to exert blocking action on GABA-activated currents as bicuculline and korlumin. It is suggested that other bicuculline-like alkaloids corresponding to isomers can exert the same effect on GABA-activated currents.

[Interaction of anemone toxin BgTX8 with the ion channels of isolated mammalian neurons]. / Vzaimodeistvie anemonotoksina BgTX8 s ionnymi kanalami izolirovannykh neironov mlekopitaiushchikh.

Interaction between anemone toxin BgTX8 and sodium channels in isolated single neurons of rat sensory ganglia was studied by voltage-clamp and intracellular perfusion techniques. It was shown that BgTX8 in external and internal solutions induced a dose-dependent slowdown of inactivation kinetics. Dissociation constant for receptor-toxin complex was found to be 4.10(-6) mol/l.

[Benzodiazepine receptors in the central nervous system of mammals]. / Retseptory benzodiazepinov v tsentral'noi nervnoi sisteme mlekopitaiushchikh.

The review describes benzodiazepine receptor in CNS of mammalians. There are two types of benzodiazepine receptors--"central" and "peripheral" with different pharmacological properties. Besides, it is possible to consider that "central" benzodiazepine receptors are not homogeneous, and are presented by two populations which fulfil different physiological role.

[Gamma-aminobutyric acid receptors in the central nervous system of mammals]. / Retseptory gamma-aminomaslianoi kisloty v tsentral'noi nervnoi sisteme mlekopitaiushchikh.

The review describes properties of gamma-aminobutyric acid (GABA) receptors in the central nervous system of mammalians. Two pharmacologically different receptors--GABAA and GABAB--are involved into GABA-ergic inhibition. GABA receptors (bicuculline-sensitive) regulate chloride permeability of membranes and can be functionally enhanced by benzodiazepine and barbiturate. GABA receptors (bicuculline-insensitive) are suggested to regulate calcium permeability.

[GABA-activated conductance of mammalian cerebellar neurons]. / GAMK-aktiviruemaia provodimost' neironov mozzhechka mlekopitaiushchikh.

GABA-activated ionic currents were studied on isolated neurons from rat cerebellum. Ions taking part in the transfer of current, potential dependence and concentration dependence of ionic channels were determined.

[Effect of the alkaloid lappaconitine on ion currents through the somatic membrane of Helix pomatia neurons]. / Vliianie alkaloida lappakonitina na ionnye toki cherez somaticheskuiu membranu neironov Helix pomatia.

The effect of alkoloid lappaconitine on ionic currents through the somatic membrane of identified neurons of the mollusc Helix pomatia was studied under voltage-clamp conditions. It is shown that 4 mM lappaconitine causes a reversible blocking action on the calcium channels. Concentration exceeding 4 mM causes irreversible changes. Lappaconitine had either an insignificant or no effect on sodium currents.

[Mechanisms of prolonged action potential generation in barium solutions]. / Mekhanizmy generatsii prodlennykh potentsialov deistviia v barievykh rastvorakh.

The membrane currents were recorded under voltage clamp from identified nerve cells of the Helix pomatia. The replacement of the external Ca ions in normal solution by Ba ions produced a shift in the potassium conduction-voltage curve along the voltage axis in the positive direction. The decrease in the limiting value of the potassium conduction was also observed. In Na-Ca-free solutions containing Na ions but no other divalent cations the inward membrane current was recorded. This current was separated into two components: an early fast inactivating (I) and a smaller long lasting component (II). It seems that the prolongation of the action potential in barium solution is due to the suppression of K conduction by Ba ions and to the existence of the long-lasting inward current.