Effect of Acute and Chronic Pretreatment with Δ1-Tetrahydrocannabinol on Motor Impairment by Ethanol in the Rat

Abstract

Pretreatment with Δ1-tetrahydrocannabinol (THC) in doses of 3–15 mg/kg produced a biphasic effect on the degree of impairment caused by ethanol (1.4 g/kg) in the performance of a motor task by the rat. Small doses of THC increased the impairment, but larger doses reversed the trend. The point of inflection occurred at a lower dose, and therefore a lower impairment, when THC was given 15 min rather than 45 min before the alcohol. None of the doses of THC had any effect on test performance in the absence of ethanol. Daily treatment with 12 mg/kg THC for 17 days caused a reversible development of tolerance to the THC augmentation of ethanol impairment, without any apparent cross-tolerance to ethanol alone.