Studies on some new indirect dopaminergic receptor agonists

The effect of some lupinyl and quinuclidinyl derivatives were examined 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-thioxantene, quinuclidinyl-phenothiazine and lupinyl-phenothiazine produce a significant increase of 3H-DA release from striatal synaptosomes while the other compounds tested were inactive. These three drugs were also able to decrease the 3H-ACh release on electrically-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.