Dopaminergic regulation of cortical acetylcholine release: effects of dopamine receptor agonists.
The regulation of the basal forebrain cholinergic system by D1 and D2 dopamine receptors was assessed in the rat using in vivo microdialysis of cortical acetylcholine. The D1 agonist CY 208-243 significantly increased cortical acetylcholine release; in contrast, the D2 agonists quinpirole and (+)-4-propyl-9-hydroxynaphthoxazine were without significant effects. Moreover, when administered in combination with CY 208-243, quinpirole failed to potentiate the D1 agonist-induced increases in cortical acetylcholine release. The non-selective dopamine receptor agonist apomorphine also increased cortical acetylcholine release, and this was completely blocked by the selective D1 receptor antagonist SCH 23390 and slightly, but not significantly attenuated by the D2 antagonist raclopride. The present results indicate that stimulation of D1 receptors activates cortically-projecting cholinergic neurons; however, a minor contribution of D2 receptors cannot be excluded.
Day
J
J
Department of Psychiatry, University of British Columbia, Vancouver, Canada.
Fibiger
H C
HC
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001552:Benzazepines / Q000494:pharmacology; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D003956:Dialysis; D004298:Dopamine / Q000502:physiology*; D015259:Dopamine Agents / Q000494:pharmacology*; D065127:Dopamine D2 Receptor Antagonists; D004873:Ergolines / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D008297:Male; D009411:Nerve Endings / Q000187:drug effects / Q000378:metabolism; D010078:Oxazines / Q000494:pharmacology; D010617:Phenanthridines / Q000494:pharmacology; D019257:Quinpirole; D020891:Raclopride; D051381:Rats; D017208:Rats, Wistar; D017447:Receptors, Dopamine D1 / Q000187:drug effects; D017448:Receptors, Dopamine D2 / Q000187:drug effects; D012457:Salicylamides / Q000494:pharmacology
D001552:Benzazepines; D015259:Dopamine Agents; D065127:Dopamine D2 Receptor Antagonists; D004873:Ergolines; D007211:Indoles; D010078:Oxazines; D010617:Phenanthridines; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D012457:Salicylamides; C054531:CY 208-243; D019257:Quinpirole; C042631:naxagolide; D020891:Raclopride; D001058:Apomorphine; D000109:Acetylcholine; D004298:Dopamine