The effect of TRH on ethanol-induced sedation in alcohol-preferring and -nonpreferring rats

TRH antagonism of ethanol sedation was evaluated in selectively-bred alcohol-preferring (P) and -nonpreferring (NP) rats. Intracerebroventricular (i.c.v.) infusions of TRH significantly reduced sleep time in the NP rats. In the P rats, TRH tended to reduce sleep, but this reduction was not significant. TRH had no significant effect on peripheral blood alcohol concentrations. The present results show that NP rats are more sensitive to the analeptic effect of TRH compared to P rats. These data support and extend those of others who have demonstrated a TRH antagonism on drug-induced sedation. Differential sensitivity to TRH may reflect differences in TRH receptor activity and/or TRH metabolism. Sensitivity to TRH analepsis may be associated with sensitivity to ethanol.