Parameters influencing the effect of delta9-THC on activity wheel behavior

In 2 studies the effect of Δ⁹-THC on activity wheel behavior in rats was examined. The amount of laboratory acclimation prior to testing was manipulated and either 4 mg/kg or 8 mg/kg Δ⁹-THC was given intraperitoneally. Activity counts were taken 15 minutes, 1, 6, 24, 48 or 72 hr after the injection. Those animals that received 4 mg/kg Δ⁹-THC and had little laboratory acclimation were significantly more active than their controls during the first 15 min but, after 1 hr were, like the other 3 experimental groups, less active than the appropriate controls. The time course for the depressant action of the Δ⁹-THC at both dose levels was quite similar and lasted for approximately 24 hr.