Dopaminergic activity of some apomorphine analogs.

The dopaminergic activity of ten apomorphine analogs was studied in rats lesioned unilaterally with 6-hydroxydopamine in the nigro-striatal system. Of these ten compounds, N,N-dimethyl-5,6-dihydroxy-2-amino-tetralin (M-7), N-methyl-5,6-dihydroxy-2-aminotetralin (M-8) and N,N-dimethyl-4,5-dihydroxy-2-aminoindan (DDAI) exhibited potent dopaminergic stimulant activity by causing the rat to turn to the unoperated side. The turning behavior of apomorphine, M-7, DDAI and d-amphetamine were antagonized by haloperidol. M-7 and DDAI also induced pecking in pigeons and their effects were also blocked by haloperidol. It is concluded that M-7, M-8 and DDAI are direct acting central dopaminergic agents.