Role of globus pallidus GABA and opiate receptors in apomorphine circling in nigro-striatal lesioned rats.
The effect of lesioning the ipsilateral globus pallidus (GP) on apomorphine-induced circling in nigro-striatal lesioned rats was investigated. A GP electrolesion almost abolished circling whereas a kainic acid lesion partly antagonized circling. Drugs that affect GABA and opiate receptors were injected in GP through a cannula. Circling was antagonized by the GABA antagonists picrotoxin and bicuculline, the GABA agonist muscimol and by baclofen. Opiate receptor agonists including morphine, levorphanol, [D-Ala2, D-Leu5]-enkephalin and beta-endorphin had no effect on circling in GP. Ethylketazocine caused a pronounced, naloxone-reversible slowing of apomorphine circling. Apomorphine-induced circling behaviour may be modulated by GP GABA receptors and kappa-type opiate receptors.
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D003342:Corpus Striatum / Q000502:physiology; D004298:Dopamine / Q000502:physiology; D004558:Electric Stimulation; D005260:Female; D005917:Globus Pallidus / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000187:drug effects*; D011963:Receptors, GABA-A; D011957:Receptors, Opioid / Q000187:drug effects*; D013238:Stereotaxic Techniques; D013239:Stereotyped Behavior / Q000187:drug effects*; D013378:Substantia Nigra / Q000502:physiology
D011956:Receptors, Cell Surface; D011963:Receptors, GABA-A; D011957:Receptors, Opioid; D001058:Apomorphine; D004298:Dopamine