Mechanisms of ethanol tolerance at a cholinergic nerve terminal

In vitro rat phrenic nerve-diaphragm preparations illustrated a concentration-dependent increase in the spontaneous release (miniature end-plate potentials, MEPPs) of acetylcholine following acute administration of ethanol. In phrenic nerve terminals from rats subjected to long-term ethanol treatmet, ethanol in vitro was significantly less effective in increasing the frequency of MEPPs. The capacity of ethanol administration to change membrane viscosity and alter sequestration of intracellular Ca2+ is discussed as a possible explanation for the observed effects.