DOES CYCLO(HIS-PRO) ACT LIKE AMPHETAMINE

In many pharmacologic tests, cyclo(His-Pro) (CHP) appears to act like a dopaminergic agonist and augments the actions of amphetamine (AMP). Therefore, to determine whether CHP is an AMP-like peptide, a comparis on between CHP and AMP was made using four separate tests known to be AMP-responsive. These include, food intake, locomotor activity, dopami ne uptake and modulation of binding sites for amphetamine and mazindol . A decrease in food intake and increase in spontaneous locomotor acti vity and stereotypy was observed after peripheral administration of am phetamine but not CHP. Chronic CHP administration resulted into a decr ease in striatal amphetamine - and increase in mazindol-binding sites; in contrast, chronic amphetamine decreased both amphetamine - and maz indol-binding sites. These results show a clear dissociation between C HP and AMP suggesting that CHP is not an amphetamine-like peptide.