Ethanol Withdrawal Alters Carbachol Responses in Selective Components of the Hippocampal Network.
L. P. Gonzalez, K. D. Marshall, and P.D. Holla.
Univ. of Oklahoma Health Sciences Center, Dept. of Psychiatry & Behavioral Sciences POB 26901, OKC, OK 73190.
Alcoholism: Clinical and Experimental Research, 25(5, Suppl.), 94A. (2003)
Previous in vivo studies in our laboratory have indicated that the responsiveness of neurons within the hippocampus is altered during withdrawal from chronic ethanol treatment, and these effects appear to be cholinergically mediated. In the current study we have begun to investigate the spatial distribution of these effects in an in vitro hippocampal slice preparation that uses a substrate- imbedded multi-electrode array (Med64) to simultaneously record extracellular field potentials from 64 electrodes across each slice. For the study reported here, male and female rats received 14 days exposure to ethanol through vapor inhalation. Five to six hours after withdrawal from ethanol treatment, hippocampal tissue slices were obtained using a standard protocol. Extracellular field potentials were recorded in response to brief electrical stimulation to several sites within the hippocampal network (perforant path, mossy fibers, and Schaffer collaterals), before and after perfusion with the cholinergic agonist carbachol. Responses in slices from ethanol-treated subjects were similar to those of controls except in the effect of carbachol on paired-pulse potentiation, and this effect was only observed in the CA1 region of the hippocampus. These results provide further support for a role of cholinergic, hippocampal mechanisms in the mediation of ethanol withdrawal.
Supported in part by NIAAA grants AA09959 & AA12283 to LPG
