Effects of acute ethanol and nicotine intake on REM sleep and its interaction with noradrenergic system in rats

Abstract

Ethanol and nicotine are the two most widely used and abused substances in the world and often are co-consumed. This study examined the effect of ethanol and nicotine co-consumption on rapid-eye-movement (REM) sleep and the role of noradrenergic system, a critical component of REM sleep control, in mediating this effect. The sleep-wake parameters were recorded for 6 hours during day-time after intraperitoneal injections of ethanol (2g/kg and 3g/kg), nicotine (0.3 and 3mg/kg), a mixture of ethanol (3gm/Kg)-nicotine (3mg/kg), and prazosin, an alpha-1 receptor antagonist (0.01 mg/kg) followed by ethanol-nicotine. The findings suggest that: a) ethanol increased NREM sleep, but suppressed REM sleep; b) nicotine suppressed both NREM and REM sleep; c) ethanol-nicotine attenuated each other’s effect on NREM sleep, but REM sleep remained depressed; and d) prazosin attenuated REM sleep suppression observed after ethanol-nicotine treatment. These findings are consistent with known interactions between ethanol and nicotine in influencing REM sleep and a role of the noradrenergic system in mediating this effect.