[Stimulating action of viadryl on the frog neuromuscular synapse]. / Stimuliruiushchee deistvie viadrila na nervno-myshechnyi sinaps liagushki.

The effect of the steroid anaesthetic "Viadril G" (hydroxydione) on the frog neuromuscular synapse and the potential of action of the muscular fibre was studied. The effect of the anaesthetic was compared with the action of the well-known stimulator of myoneural synapse--4-aminopyridine. It was revealed, that viadril increases the frequency of miniature potentials of the end plate, the amplitude and latent period of the end plate potential, reduces the amplitude of end plate miniature potentials, the time of growth and half-abate of the end plate potential. In the muscle fibre viadril does not influence significantly the resting potential, decreases the amplitude and rate of growth of the action potential and increases the time of its half-abatement. Viadril effects differ from those of 4-aminopyridine and tetraethylammonium. A supposition is made on the possible significance of the obtained results for clinical practice.

[Action of ketamine and hexenal on excitable membranes of a neuromuscular preparation in the frog]. / Deistvie ketamina i geksenala na vozbudimye membrany nervno-myshechnogo preparata liagushki.

The effects of the non-inhalation anesthetics, ketamine and hexenal (25 and 100 microM/l) on excitable membranes of the frog sartorius muscle were studied with the aid of intra- and extracellular electrodes. At the concentration 100 microM the anesthetics depressed most markedly the junctional transmission and practically had no influence on motor axon function. Since ketamine did not interact evidently with tubocurarine and showed pronounced antagonism to Mg ions, it is assumed that ketamine interferes with neuronally induced transmitter release.

[Effect of sombrevin and sodium oxybutyrate on the excitable membranes of a frog neuromuscular preparation]. / Deistvie sombrevina i natriia oksibutirata na vozbudimye membrany nervno-myshechnogo preparata liagushki.

Comparative evaluation of the effect of sombrevine and sodium hydroxybutyrate on the frog neuromuscular preparation with the use of intra- and exocellular recording of the drug-induced electrophysiological effects has shown that sombrevine inhibits the function of the excitable cell membranes whatever their functional specificity at the expense of interaction with lipid matrix of the membranes. The action of sodium hydroxybutyrate is determined by diminution of anion conduction of the excitable membranes and by an increase in their electrical resistance, which determines the hyperpolarizing action and stimulation of neuromuscular transmission in the frog skeletal muscle.