D-1 dopamine receptor stimulation potentiates neurophysiological effects of bromocriptine in rats with lesions of the nigrostriatal dopamine pathway.
Neurophysiological techniques were used to examine the possibility that the effects of bromocriptine, a direct acting dopamine agonist, can be potentiated by D-1 receptor stimulation in an animal model of parkinsonism. Single unit activity of substantia nigra pars reticulata neurons was recorded in rats with 6-hydroxydopamine induced lesions of the nigrostriatal pathway. The results showed that the coadministration of bromocriptine with the selective D-1 agonist SKF 38393 greatly attenuated pars reticulata neuronal activity at doses that did not produce significant effects when administered alone. Thus, processes elicited by D-1 receptor stimulation and bromocriptine exert synergistic effects in these 6-hydroxydopamine lesioned rats. This observation may be relevant to the mechanism underlying l-DOPA's ability to potentiate the therapeutic effects of bromocriptine in parkinsonian patients.
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001552:Benzazepines / Q000494:pharmacology*; D001971:Bromocriptine / Q000494:pharmacology*; D003342:Corpus Striatum / Q000187:drug effects; D004357:Drug Synergism; D006892:Hydroxydopamines; D008297:Male; D016627:Oxidopamine; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000502:physiology*; D017447:Receptors, Dopamine D1; D013378:Substantia Nigra / Q000187:drug effects*
D001552:Benzazepines; D006892:Hydroxydopamines; D011954:Receptors, Dopamine; D017447:Receptors, Dopamine D1; D001971:Bromocriptine; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D016627:Oxidopamine