Delta(9)-tetrahydrocannabinol enhances cortical and hippocampal acetylcholine release in vivo: a microdialysis study

The intravenous administration of synthetic cannabinoid agonists was recent ly shown to dose dependently increase acetylcholine release from the rat pr efrontal cortex and hippocampus (Eur. J. Pharmacol. 401 (2000) 179]. We rep ort here that the active ingredient of cannabis preparations, Delta (9)-tet rahydrocannabinol, administered at 10, 37.5, 75 and 150 mug/kg, dose depend ently stimulated acetylcholine release from rat prefrontal cortex and hippo campus estimated by means of in vivo brain microdialysis with vertical conc entric probes. At these doses, Delta (9)-tetrahydrocannabinol induced behav ioural stimulation. The administration of the CB1 receptor antagonist, ((N- (piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyra zole-3-carboxamidie)HCl) SR 141716A (200 mug/kg i.p.) significantly reduced the effect of Delta (9)-tetrahydrocannabinol (75 mug/kg i.v.) on acetylcho line release from rat prefrontal cortex and hippocampus. (C) 2001 Published by Elsevier Science B.V.