Striatal cannabinoid CB1 receptor mRNA expression is decreased in the reserpine-treated rat model of Parkinson's disease

High levels of both endocannabinoids and endocannabinoid receptors are pres ent in the basal ganglia. Attention has recently focused on the role of end ocannabinoids in the control of movement and in movement disorders of basal ganglia origin such as Parkinson's disease. We investigated CB1 cannabinoi d receptor mRNA expression in the reserpine-treated rat model of Parkinson' s disease using in situ hybridization. Reserpine treatment caused a topogra phically organized reduction in CB1 receptor mRNA expression in the striatu m (ranging from 11.6% medially to 53.6% laterally and dorsally). No change in CB1 receptor mRNA expression was observed in the cerebral cortex or sept um. This reduction in CB1 receptor mRNA expression may be secondary to incr eased endocannabinoid stimulation of the receptor as increased basal gangli a endocannabinoid levels have been shown to occur in this model of Parkinso n's disease. The data support the idea that cannabinoid receptor antagonist s may provide a useful treatment for the symptoms of Parkinson's disease. ( C) 2001 Academic Press.