Psychopharmacological studies on (--)-nuciferine and its Hofmann degradation product atherosperminine.

(--)-Nuciferine and its Hofmann degradation product atherosperminine showed divergent psychopharmacological effects. Because nuciferine has been reported to be a neuroleptic and atherosperminine has some chemical resemblance to dopamine, they were investigated for their dopamine-receptor activities. Nuciferine had a pharmacologic profile of action associated with dopamine-receptor blockade; i.e., it induced catalepsy, inhibited spontaneous motor activity, conditioned avoidance response, amphetamine toxicity and stereotypy. On the other hand, atherosperminine produced effects associated with dopamine receptor stimulation, i.e., stereotypy, increase in spontaneous motor activity and amphetamine toxicity, reversal of haloperidol-induced catalepsy and inhibition of conditioned avoidance response, inhibition of morphine analgesia, and potentiation of the anticonvulsant action of diphenylhydantoin. The results are discussed on the basis of the chemical configuration of the two compounds.