Δ9-Tetrahydrocannabinol increases brain temperature and inverts circadian rhythms

Delta (9)-tetrahydrocannabinol (THC) has been shown to protect against focal and global ischemia. Hypothermia is thought to be one mechanism for this protection. These observations are important since brain hyperthermia is known to increase ischemic damage while hypothermia is protective. To establish the effect of THC on brain and body core temperature, brain and body temperature probes were inserted for chronic temperature monitoring (n = 20). THC treated groups were administered THC at either low (0.1 mg/kg) or high (10 mg/kg) dose for 1 week. Brain temperature was recorded during this period and for I week following the discontinuation of THC. Chronic administration of THC at either dose increased brain temperature (p < 0.0001) but did not significantly change body core temperature (p = 0.4767) in the freely moving rat. NeuroReport 12:3791-3794 (C) 2001 Lippincott Williams & Wilkins.