Effects of intraaccumbens dopamine agonist SK&F38393 and antagonist SCH23390 on locomotor activities in rats.

The present study examined the effects of the dopamine D1 and D5 subtype receptors agonist, R(+)-1-phenyl-2,3,4,5-tetrahydro-(1H)-3-benzazepine-7,8-diol (SK&F38393), and antagonist, R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-ben zaz epine (SCH23390), on locomotor activities after bilateral microinjection into the nucleus accumbens (Acb). SK&F38393 (0.1-10.0 micrograms) significantly potentiated and SCH23390 (0.01-1.0 microgram) significantly attenuated locomotor activity as measured by horizontal distance in cm. The data were supportive of the hypothesis that dose-related locomotor activities induced by microinjections of SK&F38393 into the Acb are independently mediated by D1 and D5 subtype receptors.