Behavioral Effects of Delta-9-Tetrahydrocannabinol Under Hyperbaric Air.
Medical research progress rept.,
NAVAL MEDICAL RESEARCH INST BETHESDA MD
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As part of a continuing research program investigating drugs that may be used in hyperbaric conditions, the present study was undertaken to determine the behavioral effects of delta-9-tetrahydrocannabinol, the main psychoactive ingredient of marijuana. Operant techniques were used to establish sensitive baseline patterns of behavior in rats. Dose-response curves were determined for 0.5, 1.0, 2.0, and 4.0 mgkg at 1, 3, 5, and 7 ATA with the animals breathing compressed air. As expected, dose-dependent decrements in performance were observed at 1-ATA conditions. Under the elevated pressure conditions, however, a reversal of behavioral toxicity occurred, where performance at 5 and 7 ATA was improved over that at surface with equivalent doses of the drug. These data suggest that the pressure reversals of anesthetics and analgesics that are reported at much greater pressures may well be detected at lower levels of pressure if more sensitive measures are utilized.