Hayakawa K, Mishima K, Abe K, Hasebe N, Takamatsu F, Yasuda H, Ikeda T, Inui K, Egashira N, Iwasaki K, Fujiwara M.
Cannabidiol, a non-psychoactive constituent of cannabis, has been
reported as a neuroprotectant. Cannabidiol and
Delta(9)-tetrahydrocannabinol, the primary psychoactive constituent of
cannabis, significantly decreased the infarct volume at 4 h in the mouse
middle cerebral artery occlusion model. The neuroprotective effects of
Delta(9)-tetrahydrocannabinol but not cannabidiol were inhibited by
SR141716, a cannabinoid CB1 receptor antagonist, and were abolished by
warming of the animals to the levels observed in the controls.
Delta(9)-Tetrahydrocannabinol significantly decreased the rectal
temperature, and the hypothermic effect was inhibited by SR141716. These
results surely show that the neuroprotective effect of
Delta(9)-tetrahydrocannabinol are via a CB1 receptor and
temperature-dependent mechanisms whereas the neuroprotective effects of
cannabidiol are independent of CB1 blockade and of hypothermia.