The effect of beta-casomorphins on the apomorphine- and amphetamine-induced turning after nigral lesions in rats.
To characterize the action of derivatives of beta-casomorphin their influence on the apomorphine- or amphetamine-induced turning behaviour following unilateral lesion of the substantia nigra with 6-hydroxydopamine was investigated. The beta-casomorphins studied, (D-Pro4-beta-casomorphin1-5, D-Phe3-beta-casomorphin1-5, Des-Tyr1-D-Pro4-beta-casomorphin2-5 or Des-Tyr1-D-Phe3-beta-casomorphin2-5), did not change postsynaptic dopaminergic processes in the striatum of the rat after intraperitoneal injection of apomorphine. On the contrary, the turning induced by amphetamine was modified by beta-casomorphins. Increased amphetamine-evoked turning could be observed after intrastriatal application of tyrosine-containing beta-casomorphins (D-Pro4-beta-casomorphin1-5 or D-Phe3-beta-casomorphin1-5), whereas presynaptic dopaminergic mechanisms were inhibited by injection of the corresponding des-tyrosine beta-casomorphin analogs (Des-Tyr1-D-Pro4-beta-casomorphin2-5 or Des-Tyr1-D-Phe3-beta-casomorphin2-5) into the striatum after administration of amphetamine.
D000661:Amphetamine / Q000494:pharmacology*; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D003342:Corpus Striatum / Q000187:drug effects*; D004347:Drug Interactions; D004723:Endorphins / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013239:Stereotyped Behavior / Q000187:drug effects*; D013378:Substantia Nigra / Q000187:drug effects* / Q000502:physiology
D004723:Endorphins; C021968:beta-casomorphins; D000661:Amphetamine; D001058:Apomorphine