Effects of alcohols upon pacemaker activity in neurons of Aplysia californica.

1. Alcohols have been used as pharmacological tools to probe the nature of action-potential gates and channels. In this study, we examine the effects of alcohols upon activity patterns in Aplysia neurons. 2. Ethanol at concentrations of 0.4-0.6 M induces bursting pacemaker activity (BPA) in previously silent cells. The same effect is produced with 40-60 mM concentrations of butanol, suggesting that this induction is not due to osmotic effects. 3. Voltage-clamp measurements indicate that the induction of BPA is accompanied by the appearance of a negative-slope resistance (NSR) region in the steady-state current-voltage relationship of the cell. The induction of BPA and a NSR region in silent cells is antagonized by lowered temperatures. 4. Ethanol concentrations which produce BPA and a NSR region in silent cells abolish both of these normally present characteristics in endogenous bursters. This suggests that whatever membrane components are moved into optimal configuration for the expression of BPA in silent cells are shifted out of optimal configuration in endogenous bursters, by similar ethanol concentrations.