Blocking of the effect of Δ 1tetrahydrocannabinol (ΔTHC) on spontaneous motor activity in the rat by immunization with a protein conjugate of Δ 1THC

Abstract

Rats actively immunized with porcine gamma globulin- hemisuccinate- Δ 1-tetrahydrocannabinol (PγG-HS-Δ 1THC) showed higher spontaneous motor activity after intraperitoneal administration of Δ 1THC at a dose of 10 mg. per kg. than did rats immunized with a control antigen, porcine gamma globulin-hemisuccinate-phenol (PγG-HS-Phenol). The capacity to neutralize the effect of Δ 1THC was found to depend on the degree of immunization; thus, the difference in mean spontaneous motor activity after injection of Δ 1THC was significant in rats which had received five injections of the immunogen over a period of 86 days, and not in those which had received only two injections over a period of 34 days. In view of the observations that Δ 1-tetrahydrocannabinol induces a decrease in spontaneous motor activity in rats, the observed neutralization of the effect of δ 1THC in animals receiving multiple injections of protein conjugates of Δ 1THC may be due to the binding of the drug by anti-THC antibodies (which are expected to be produced on active immunization with these conjugates), thus preventing Δ 1THC from reaching drug-receptor sites.