(-)-Norpseudoephedrine, but not (+/-)-amphetamine, prevents the increase in fluid intake associated with ethanol presentation in rats.

The effects of daily intraperitoneal administration of (+/-)-amphetamine (AMPH: 4 mg/kg) and (-)-norpseudoephedrine (NPE: 15 or 30 mg/kg) on drinking were evaluated in rats allowed to drink water or a 5% ethanol solution during the 5 h following drug administration. AMPH, but not NPE, significantly increased water intake. Substitution of ethanol for water produced a significant increase in fluid intake in the control group, whereas drinking levels remained unchanged in both AMPH and NPE treated rats. Discontinuation of drug treatment during the regimen of ethanol presentation produced a prompt increase in fluid intake in the NPE, but not AMPH, treated groups. Finally, substitution of water for ethanol led to a significant reduction of fluid intake in all the groups. These results suggest that a light (i.e. NPE), but not a strong (i.e. AMPH) psychomotor stimulant, is able to weaken rewarding properties of diluted ethanol.