Effects of Δ9-THC on the Synaptosomal Uptake of 3H-Tryptophan and 3H-Choline

Abstract

The in vitro addition of (–)-Δ⁹-tetrahydrocannabinol (Δ⁹-THC) resulted in a dose-responsive inhibition of the high-affinity specific synaptosomal uptake of both ³H-tryptophan and ³H-choline in mouse forebrain crude synaptosomal preparations. The approximate concentrations of Δ⁹-THC required to cause a 50% inhibition of the uptake of ³H-tryptophan and ³H-choline were 33 and 16 μM, respectively. Kinetic analysis showed that inhibition of both compounds were consistent with a noncompetitive mechanism. The pretreatment of mice with doses of 10, 30 or 100 mg/kg Δ⁹-THC had no effect on the subsequent in vitro synaptosomal uptake of either ³H-tryptophan or ³H-choline into forebrain synaptosomes.