EXPRESSION OF STEREOTYPED BEHAVIOR REQUIRES STIMULATION OF NIGRAL D-1DOPAMINE-RECEPTORS

Dopamine receptors in the pars reticulata of the substantia nigra were inactivated following bilateral injections of N-ethoxycarbonyl-2-etho xy-1,2-dihydroquinoline (EEDQ). Loss of D-1, but not D-2, receptors wa s associated with a significant decrease in the incidence of stereotyp ed head-down sniffing elicited by the mixed D-1/D-2 receptor agonist, apomorphine. The results support the hypothesis that D-1 receptors in the substantia nigra are necessary for the expression of dopamine medi ated stereotyped behaviour.