NITRENDIPINE PREVENTS THE DECREASE CAUSED BY CHRONIC ETHANOL INTAKE IN THE MAINTENANCE OF TETANIC LONG-TERM POTENTIATION

Prolonged ethanol consumption has previously been reported to decrease long-term potentiation (LTP) in isolated hippocampal slices. Dihydrop yridine calcium channel antagonists, such as nitrendipine, have been p reviously found to prevent some of the adaptive responses to chronic e thanol intake. The present study investigated the effects of concurren t in vivo administration of nitrendipine and ethanol on LTP in isolate d mouse hippocampal slices. LTP was produced by either one or two teta nic stimuli or by increased calcium. When one tetanus was used, althou gh the potentiation of the population spike height was less after the ethanol treatment, the difference was not quite significant. However, the potentiation after in vivo administration of ethanol plus nitrendi pine was significantly greater than after ethanol alone. When two teta nic stimuli were applied, the maintenance of the potentiation of the p opulation spike height was significantly decreased by the chronic etha nol treatment. This decrease was not seen when nitrendipine was given with the ethanol. When LTP was produced by a transient increase in the calcium concentration in the bathing medium, the chronic ethanol trea tment did not alter the potentiation of the population spike height, b ut in vivo treatment with ethanol plus nitrendipine decreased the pote ntiation.