Muricide induced by single injection of delta9-tetrahydrocannabinol

Male rats were subjected to 22 hr of food deprivation and 24 hr of isolated housing and then Δ⁹-tetrahydrocannabinol (THC) was intraperitoneally injected. One hour after treatment, the dose-related muricide was observed. Next, the relationship between the duration of isolated housing and muricide was investigated. Regardless of the time at which THC was injected during periods of isolation ranging from 2 hr to 30 days, or even the animals were isolated concurrently to THC injection, muricide appeared at an incidence of 60–80%, and was unrelated to the duration of isolated housing. Muricide was not induced in communally housed rats treated with THC, but by placing these animals in isolation 1 hr after treatment, the time of peak effect of THC, muricide occurred in 70% of the rats. These results demonstrate that if the rat is placed in isolation within the period of the effect of THC, muricide is induced.