Dopaminergic agents including 3-PPP and its enantiomers on medial septal self-stimulation.
The effects of several dopamine agonists were determined on medial septal self-stimulation in rats and compared with selected dopamine antagonists and with the psychostimulants, d-amphetamine and nomifensine. Apomorphine, 3-PPP, TL-99, N,N-dipropyl-5,6-ADTN and N,N-dipropyl-6,7-ADTN inhibited self-stimulation at dose ranges selective for the dopamine autoreceptor as indicated by biochemical studies. Haloperidol and molindone produced dose-related inhibition but sulpiride increased self-stimulation. D-amphetamine and nomifensine also increased responding. The agonist-induced inhibition differed from neuroleptic-induced inhibition of self-stimulation. Both (+) and (-) 3-PPP inhibited responding by a similar amount over the dose range 0.25-1.0 mg/kg. At higher doses, (-) 3-PPP further decreased responding whereas the effects of (+) 3-PPP plateaued at approximately 55% of controls. These studies show that dopamine agonists, like neuroleptics, inhibit medial septal self-stimulation. This effect appears to be mediated via autoreceptor activation. Differences between neuroleptic- and agonist-induced inhibition and the 3-PPP stereoisomer data accord with the hypothesis that behavioural inhibitory effects caused by autoreceptor activation are less severe than those caused by dopamine postsynaptic blockade.
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001067:Appetite Depressants / Q000494:pharmacology; D001552:Benzazepines / Q000494:pharmacology; D003913:Dextroamphetamine / Q000494:pharmacology; D004347:Drug Interactions; D006220:Haloperidol / Q000494:pharmacology; D008297:Male; D009627:Nomifensine / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology*; D051381:Rats; D011954:Receptors, Dopamine / Q000187:drug effects*; D012653:Self Stimulation / Q000187:drug effects*; D013237:Stereoisomerism; D013469:Sulpiride / Q000494:pharmacology; D013764:Tetrahydronaphthalenes / Q000494:pharmacology
D001067:Appetite Depressants; D001552:Benzazepines; D010880:Piperidines; D011954:Receptors, Dopamine; D013764:Tetrahydronaphthalenes; D009627:Nomifensine; C015842:2-(N,N-dipropyl)amino-5,6-dihydroxytetralin; C037253:2-(N,N-dipropyl)amino-6,7-dihydroxytetralin; C016893:2-(N,N-dimethylamino)-6,7-dihydroxytetralin; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D013469:Sulpiride; C026539:preclamol; D006220:Haloperidol; D001058:Apomorphine; D003913:Dextroamphetamine