Studies on some new indirect dopaminergic receptor agonists

The effects of some lupinyl and quinuclidinyl derivs. were examd. on the release of dopamine (DA) and acetylcholine (ACh) and on the dopaminergic receptors in the rat corpus striatum in comparison with promazine. All the drugs tested were inactive on the spontaneous release of 3H-ACh from striatal synaptosomes. Lupinyl-thioxanthene, quinuclidinyl-phenothiazine and lupinyl-phenothiazine produced a significant increase of 3H-DA release from striatal synaptosomes whereas the other compds. tested were inactive. These 3 drugs decreased the 3H-ACh release on elec.-evoked striatal slices throughout the activation of the release of endogenous DA, but they did not possess antagonistic effects on the dopaminergic receptors which modulate ACh release. The potential use of these agents in parkinsonism therapy is discussed.