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 comparison between CHP and AMP was made using four separate tests known to be AMP-responsive. These include, food intake, locomotor activity, dopamine uptake and modulation of binding sites for amphetamine and mazindol. A decrease in food intake and increase in spontaneous locomotor activity and stereotypy was observed after peripheral administration of amphetamine but not CHP. Chronic CHP administration resulted into a decrease in striatal amphetamine - and increase in mazindol-binding sites; in contrast, chronic amphetamine decreased both amphetamine - and mazindol-binding sites. These results show a clear dissociation between CHP and AMP suggesting that CHP is not an amphetamine-like peptide.
Mizuma
H
H
Department of Medicine, Louisiana State University Medical Center, New Orleans 70112.
Shimizu
I
I
Hilton
C
C
Prasad
C
C
D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D003913:Dextroamphetamine / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism*; D005215:Fasting; D005247:Feeding Behavior / Q000187:drug effects*; D008297:Male; D008454:Mazindol / Q000378:metabolism; D009043:Motor Activity / Q000187:drug effects*; D014179:Neurotransmitter Uptake Inhibitors / Q000494:pharmacology*; D010456:Peptides, Cyclic / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011954:Receptors, Dopamine / Q000187:drug effects / Q000378:metabolism; D013239:Stereotyped Behavior / Q000187:drug effects
D014179:Neurotransmitter Uptake Inhibitors; D010456:Peptides, Cyclic; D010879:Piperazines; D011954:Receptors, Dopamine; D008454:Mazindol; C015924:histidyl-proline diketopiperazine; D003913:Dextroamphetamine; D004298:Dopamine