Repeated ethanol withdrawal delays development of focal seizures in hippocampal kindling.

Clinical studies report an increase in the prevalence of alcohol withdrawal-related seizures in patients with a history of multiple detoxifications. In order to investigate the alcohol withdrawal-related alterations in neural activity that lead to this increase in seizure propensity, basic researchers have examined both spontaneous and elicited seizures in animals undergoing withdrawal from chronic ethanol. This study was designed to further examine alcohol withdrawal-related seizure activity in a rodent model by assessing the development of electrical kindling after chronic ethanol exposure administered in multiple or single treatment episodes. Laboratory rats were exposed to either five periods of 3 days of ethanol, one 15-day period of continuous ethanol, or a period of control handling with no ethanol exposure. Ten days after a final withdrawal episode, all animals were surgically prepared with recording and stimulating electrodes. Twenty days after final withdrawal from ethanol or an equivalent period of similar handling, daily electrical stimulation of hippocampal area CA3 was initiated. Animals exposed to ethanol required more daily stimulations to become fully kindled than did ethanol-naive controls, with those animals experiencing five withdrawals requiring the most stimulations overall and more stimulations to progress from focal to generalized seizure behaviors. These results indicate that chronic ethanol exposure and withdrawal alter neuronal mechanisms important for hippocampal kindling in a manner that persists long after cessation of ethanol exposure, and they indicate that this effect is increased by exposure to repeated withdrawal episodes.