D2 dopamine receptor activation inhibits basal and forskolin-evoked acetylcholine release from dissociated striatal cholinergic interneurons.
We tested whether D2 ligands inhibit basal and forskolin-stimulated [3H]ACh release from dissociated striata, as opposed to striatal slices. Quinpirole inhibited both basal (40% maximal inhibition; IC50 approximately 50 nM) and 10 microM forskolin-stimulated release (80% inhibition; IC50 approximately 25 nM quinpirole) and both actions were blocked by a D2 antagonist. Vesamicol prevented the quinpirole and forskolin actions. The ability of D2 agonists to inhibit basal and cyclase-stimulated acetylcholine release emanating from vesamicol-sensitive vesicles appears to be tonically suppressed by inhibitory elements within striatal circuitry.
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Department of Neurology, University of Virginia Health Sciences Center, Charlottesville 22908, USA. ivan@nerve.med.virginia.edu
D000109:Acetylcholine / Q000378:metabolism*; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D005576:Colforsin / Q000494:pharmacology*; D018491:Dopamine Agonists / Q000494:pharmacology*; D018492:Dopamine Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D007395:Interneurons / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D017072:Neostriatum / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009467:Neuromuscular Depolarizing Agents / Q000494:pharmacology; D010275:Parasympathetic Nervous System / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010880:Piperidines / Q000494:pharmacology; D019257:Quinpirole / Q000037:antagonists & inhibitors / Q000494:pharmacology; D051381:Rats; D017448:Receptors, Dopamine D2 / Q000187:drug effects / Q000378:metabolism*; D012457:Salicylamides / Q000037:antagonists & inhibitors / Q000494:pharmacology
D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D009467:Neuromuscular Depolarizing Agents; D010880:Piperidines; D017448:Receptors, Dopamine D2; D012457:Salicylamides; D005576:Colforsin; D019257:Quinpirole; C006189:vesamicol; D000262:Adenylyl Cyclases; C045989:eticlopride; D000109:Acetylcholine