Cannabinoid Receptor Type 1 - Expression - Brain - Basal Ganglia

Basal Ganglia

CB₁ receptors are expressed throughout the basal ganglia and have well established effects on movement in rodents. As in the hippocampus, these receptors inhibit the release of glutamate or GABA transmitter, resulting in decreased excitation or reduced inhibition based on the cell they are expressed in. Consistent with the variable expression of both excitatory glutamate and inhibitory GABA interneurons in both the basal ganglia's direct and indirect motor loops, synthetic cannabinoids are known to influence this system in a dose-dependent triphasic pattern. Decreased locomotor activity is seen at both higher and lower concentrations of applied cannabinoids, while an enhancement of movement may occur upon moderate dosages. However, these dose-dependent effects have been studied predominately in rodents and the physiological basis for this triphasic pattern warrants future research in humans. Effects may vary based on the site of cannabinoid application, input from higher cortical centers, and whether drug application is unilateral or bilateral.