Correlation between the dose and development of acute tolerance to the hypothermic effect of THC.

ABSTRACT

The administration of 0.3-40 mg/kg delta 9-tetrahydrocannabinol (THC) produced a dose-dependent hypothermia in rats. The maximal hypothermic effect was obtained with the dose of 2.5 mg/kg of THC. When the same doses of THC were repeated on days 2 and 3, tolerance to the hypothermic effect of THC was apparent. Doses of THC higher than 2.5 mg/kg induced a significant and dose-dependent tolerance after the first administration whereas with the lower doses, tolerance was only apparent after the second injection. The possible mechanism of these effects of THC is discussed.