Effects of D1 and D2 antagonists on apomorphine-induced responses of ventral pallidal neurons.
The ventral pallidum with the adjacent substantia innominata (VP) has been described as a dopaminoceptive brain region. Repeated systemic injections of the dopamine agonist, apomorphine, induce dose-dependent alterations in VP neuronal activity. The present studies evaluated the contribution of D1 and D2 receptor subtypes to apomorphine-induced alterations in extracellularly recorded VP neuronal activity. Both sulpiride (D2 antagonist) and SCH23390 (D1 antagonist) attenuated many of these responses; however, pretreatment with either antagonist did not alter the number of responding neurons, or the maximal effect induced by apomorphine. Thus, activation of either receptor subtype by apomorphine is sufficient to initiate the observed responses, and both may be involved in dopaminergic modulation of VP neurons.
Maslowski
R J
RJ
Department of Pharmacology and Experimental Therapeutics, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153.
Napier
T C
TC
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D001552:Benzazepines / Q000494:pharmacology*; D005071:Evoked Potentials / Q000187:drug effects; D005917:Globus Pallidus / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects / Q000502:physiology*; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D013469:Sulpiride / Q000494:pharmacology*
D001552:Benzazepines; D011954:Receptors, Dopamine; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D013469:Sulpiride; D001058:Apomorphine