Acute effects of alcohol on photic evoked potentials of rats: lateral geniculate nucleus and reticular formation.

This study examined the effects of ethanol on photic evoked potentials recorded from the dorsal lateral geniculate nucleus (LGN) and midbrain reticular formation (MRF) of chronically implanted albino rats. Animals were given intraperitoneal injections of saline, or of 0.5, 1.0, 1.5 or 2.5 g ethanol/kg body weight on separate days. Evoked potentials were recorded at 5, 20, 40 and 60 min following injection. An early positive component recorded from each structure was depressed in amplitude by only the 2.5 g/kg alcohol dose, while the succeeding negative component was depressed by both the 1.5 and 2.5 g/kg doses. Latencies of both early components in each structure were increased by the 1.5 and 2.5 g/kg alcohol doses. Alcohol doses of 1.0-2.5 g/kg depressed the amplitude of a later positive component in the LGN (latency of 78 msec), but latency was not altered. In contrast, a late positive component in the MRF (latency of 150 msec) was both decreased in amplitude and increased in latency by only the 2.5 g/kg dose. These results on subcortical structures are discussed in relation to alcohol's effects on cortical evoked potentials.