[Effect of cholinesterase inhibitors on the electrical excitability of the membrane of frog muscle fiber]

Abstract

The effects of reversible (galanthamine, eserine) and irreversible organophosphate (armine) cholinesterase inhibitors on excitable muscle fibre membrane of the frog involved elongation of the rise and the half-decay time of the AP (galanthamine and eserine), the critical level of depolarization being shifted to a more negative value. Armine decreased the rise and the half-decay time, the critical level of depolarization being shifted to the positive direction; subsequent rising of the threshold often caused blocking of neuro-muscular transmission during the first minutes of the armine action, pretreatment of preparations with galanthamine (eserine) preventing the threshold increase and armine blocking of transmission. Probably mechanism of these drugs action on the membrane channels is discussed. The negative shift of critical level seems to underlie the protective action of galanthamine and eserine in case of poisoning with irreversible cholinesterase inhibitors.