[abstract] BEHAVIORAL EFFECTS OF THE INTERACTION OF MARIJUANA AND INCREASING PARTIAL PRESSURES OF N2 and O2.

Abstract

Previous research has indicated that the behaviorally toxic effects of delta-9-tetrahydrocannabinol (THC), the main psychoactive ingredient in marijuana, can be attentuated by increased pressures of air. The present study sought to separate out the effects of the increased partial pressures of nitrogen and oxygen in an attempt to determine what influences the apparent drug antagonism. Long-Evans rats were trained by operant techniques to emit steady-state performance baselines on a difficult task involving three different behaviors. To determine the specific effect of each of the principal gases involved (N2, O2), we generated dose-response curves by injecting 1.0, 2.0, or 4.0 mg/kg THC and evaluated behavior at 0.8, 2.7, 4.0, and 5.6 ATA N2 with the PO2 maintained at either 0.2, 0.4, or 0.8 ATA O2. Results indicate a complex interaction between the dose of the drug and increasing partial pressures of both nitrogen and oxygen. In general, the greatest attentuation of drug effects results from moderate increases in partial pressures of both nitrogen and oxygen.