Pharmacological interaction of the effects of delta 9-trans-tetrahydrocannabinol and cannabidiol on serum corticosterone levels in rats.

The pharmacological interaction of the effects of delta 9-trans-tetrahydrocannabinol (delta 9-THC) and cannabidiol (CBD) on serum corticosterone levels in rats was studied in two experimental situations: simultaneous administration of the two cannabinoids, or administration of one followed by the other 24 hr later. Forty-five min after administration, both delta 9-THC (1, 2 and 4 mg/kg) and CBD (10, 30 and 60 mg/kg) induced a dose-dependent increase in corticosterone levels. The effect of the mixture delta 9-THC (2 mg/kg) with CBD (10, 30 and 60 mg/kg) did not differ significantly from that produced by CBD alone. We also observed that CBD (30 mg/kg), 24 hr after administration, potentiated the effect of delta 9-THC (2 mg/kg) even though it had no effect on corticosterone levels. This delayed interference of CBD with delta 9-THC effects was attributed to a pharmacokinetic interaction between the two cannabinoids.