Dopamine autoreceptor reserve in vitro: Possible role of dopamine D-3 receptors

Receptor alkylation in vivo with N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) decreased the potency, but not the efficacy, of the dopamine D-3 receptor-preferring agonist 7-hydroxy-N, N-di-n-propyl-2-aminotetralin (7-OH DPAT) at synthesis modulating dopamine autoreceptors in striatal and olfactory tubercle slices stimulated by 30 mM K+. In contrast, 7-OH-DPAT was ineffective in slices exposed to forskolin (10 mu M). The results support the presence of autoreceptor reserve in vitro, and the partial involvement of dopamine D, receptors in the autoregulation of dopamine synthesis.