Changes in physostigmine-induced hippocampal seizures during ethanol withdrawal

Hippocampal cholinergic neurons are sensitive to acute ethanol administration, and specific alterations are seen in the functioning of these neurons following chronic ethanol. The present study examined the effects of chronic ethanol exposure and withdrawal on the sensitivity of the hippocampus to local injection of physostigmine, an inhibitor of acetylcholine metabolism. While intrahippocampal physostigmine elicited hippocampal seizure activity in 80% of the animals tested during withdrawal from chronic exposure to low levels of ethanol, seizure activity was elicited in only 30% of ethanol-naive subjects. These results suggest that chronic ethanol exposure may increase the sensitivity of hippocampal neurons to cholinergic stimulation, and that some of the symptoms of ethanol withdrawal may be related to this change.