Effects of mescaline, [ Δ9]-tetrahydrocannabinol and pentobarbital on the auditory evoked responses in the cat

Abstract

Effects of mescaline, [ Δ 9]-tetrahydrocannabinol ([ Δ 9]-THC) and pentobarbital were studied on the peak latency, area and amplitude of the waves (positive P 1 and negative N 1) of the averaged auditory evoked potentials in restrained conscious cats. Mescaline (5–15 mg/kg i.p.) caused a significant increase in peak latency (8–13%), area (77–195%) and amplitude (38–128%) of these waves. The onset of these changes was within 10–40 min and their duration ranged between 90–180 min. [ Δ 9]-THC (0.5–2 mg/kg in 4% Tween 80 i.p.) also caused a marked increase in peak latency, area and amplitude (10–25%, 113–370% and 66–310% respectively), while Tween 80 caused slight and variable effects. The effects of [ Δ 9]-THC had its onset within 40–105 min and lasted for more than 120–180 min. Pentobarbital (20 mg/kg i.p.) also caused an increase in the peak latency (8–23%), area (94–121%) and amplitude (119–132%) of these waves within 5–7 min. The peak effect occurred within 10–15 min and lasted for more than 100–120 min. These effects of the hallucinogens, mescaline and [ Δ 9]-THC thus appear to resemble those of pentobarbital, a central nervous system depressant; however the mechanism of their actions differs.