EFFECTS OF PSYCHOTRIA-COLORATA ALKALOIDS IN BRAIN OPIOID SYSTEM

An ethnopharmacological survey showed that home remedies prepared with flowers and fruits of Psychotria colorata are used by Amazonian peasa nts as pain killers. Psychopharmacological in vivo evaluation of alkal oids obtained from leaves and flowers of this species showed a marked dose-dependent naloxone-reversible analgesic activity, therefore sugge sting an opioid-like pharmacological profile. This paper reports an in hibitory effect of P. colorata flower alkaloids on [H-3]naloxone bindi ng in rat striata as well as a decrease in adenylate cyclase basal act ivity. The alkaloids did not affect [H-3] GMP-PNP binding. These findi ngs provide a neurochemical basis for the opioid-like activity previou sly detected in vivo and point to Psychotria alkaloids as a potential source of new bioactive opiate derivatives.