SENSITIVITY TO STRYCHNINE SEIZURES IS UNALTERED DURING ETHANOL WITHDRAWAL

Previous research from this laboratory has indicated that animals chro nically exposed to ethanol and then withdrawn exhibit a variety of sym ptoms of central nervous system hyperexcitability that occur in unique clusters. These clusters of symptoms were observed to differ in their duration and in the time of onset relative to the time of ethanol wit hdrawal. In addition, the observed clusters of spontaneous seizure eve nts in these animals were seen to correlate with differences in sensit ivity to seizure-inducing treatments. These results suggest that seizu re sensitivity during ethanol withdrawal may indicate the involvement of multiple, independent, neuronal mechanisms. To investigate this pos sibility further, the following study examined the sensitivity of etha nol-withdrawn animals to seizures induced by the glycine antagonist st rychnine. Seizure sensitivity to strychnine was evaluated at the same times following ethanol withdrawal when animals were previously seen t o show the differential occurrence of spontaneous seizure events and a lso differences in sensitivity to picrotoxin-induced seizures. Ethanol -withdrawn animals did not differ in their responses to strychnine com pared with ethanol-naive controls at any of the times tested. This lac k of change in seizures induced by antagonism of glycine inhibition oc curred in spite of the increased sensitivity of similarly treated anim als to picrotoxin-induced seizures at the same test times. These data suggest that chronic ethanol exposure and withdrawal may not significa ntly alter the function of glycinergic inhibitory neurotransmission an d that the ethanol withdrawal syndrome is indicative of alterations in specific neuronal mechanisms rather than of a generalized state of ce ntral nervous system hyperexcitability.