**7.3** *Picralima nitida* **Stampf Th. et H. Dur.**

*Picralima nitida* is the only species of the genus Picralima and it is related to Hunteria and Pleiocarpa. it belongs to the apocynaceae family. *P. nitida* has widely varied applications in West Africa folk medicine. The indole alkaloid alstonine was identified as the major component of the fruit rind of *P. nitida*, a plant-based treatment administered to psychotic patients in Nigeria [34]. Alstonine was given prior to apomorphine/ amphetamine administration and observed for climbing behavior and stereotypy, the effect of the alkaloid on haloperidol-induced catalepsy was also assessed [89]. Further studies of alstonine showed a clear antipsychotic profile in rodents, closer to atypical than to typical antipsychotics. Apparently, apomorphine induced stereotypy and amphetamine-induced lethality were significantly reduced by alstonine, suggesting a decrease in mesolimbic dopamine, alstonine reversed haloperidol-induced catalepsy, indicating that nigrostriatal dopamine transmission is not lessened [89]. Alstonine was found to reduce negative symptoms, through a mechanism involving 5HT2A,C receptors, and reverses interaction deficits induced by MK801 [90]. Further studies by Linck et al. [35] indicated that alstonine indirectly modified DA receptors, precisely by modifying DA uptake. This unique mechanism for DA transmission modulation backs the antipsychoticlike effects of alstonine and is attuned with its behavioral profile in mice and apparent effects in patients. These findings may signify an innovation in the antipsychotic development field [35].
