Chronic ethanol treatment differentially affects muscarinic receptor responses in rat hippocampus.

Sensitivity of hippocampal field potentials to local (iontophoretic) application of acetylcholine (ACh) was investigated in chronic ethanol treated (CET) and sucrose-fed (control) rats. CET and control rats were fed a liquid diet containing either ethanol or sucrose for 28 weeks. Five to six months after ethanol or sucrose was withdrawn, hippocampal slices were taken and ACh was applied in stratum pyramidale or stratum radiatum of CA1 to observe population spike facilitation or field EPSP inhibition, respectively. Population spikes were facilitated to a considerably lesser extent in CET slices relative to controls, while no treatment differences were observed for dendritic EPSP inhibition. These data suggest that ACh response properties in CA1 exhibit differential sensitivity to CET, and may reflect a distinct susceptibility of muscarinic receptor subtypes to the neurotoxic effects of ethanol.