Cannabinoid modulation of prefrontal cortex and hippocampus neuronal functioning has been correlated to the disruptive action of marijuana on memory tasks. This study investigates the effects of delta(9)-tetrahydrocannabinol (delta(9)-THC) on dopamine, glutamate and GABA levels in vivo by brain microdialysis in the prefrontal cortex. Delta(9)-THC (1 mg/kg, i.v.) significantly increased extracellular dopamine and glutamate levels and decreased GABA levels. These effects were prevented by the cannabinoid antagonist SR141716A (1 mg/kg, i.v.), which per se was ineffective. These results suggest that delta(9)-THC disrupt the normal interplay between neurotransmitters in this area and may bear relevance in understanding neuronal mechanisms underlying cannabinoid-induced cognitive deficits.
Copyright 2002 Elsevier Science B.V.