title: Serotonin inhibits acetylcholine release from rat striatum slices: evidence for a presynaptic receptor-mediated effect.
abstract: Rat brain striatum slices were incubated with [3H]choline, perfused with a physiological buffer, and stimulated by perfusion with a K+-enriched buffer for 2 min. The tritium overflow evoked by K+ was decreased by 5-hydroxytryptamine (serotonin, 5-HT) (maximal inhibition 10(-6) M). This effect of 5-HT was mimicked by several agonists (5-methoxytryptamine, N,N-dimethyl-tryptamine, bufotenin) and blocked by serotonergic antagonists (methiothepin, methysergide, cinanserin) but not by haloperidol; methiothepin and methysergide alone slightly increased the K+-evoked overflow of tritium (3H). Inhibition of the tritium release by 5-HT was not suppressed in the presence of tetrodotoxin (TTX) (10(-6) M). These results suggest that 5-HT tonically inhibits acetylcholine (ACh) release from striatal cholinergic neurons by acting on a presynaptic receptor localized on cholinergic terminals.
mesh_terms: D000109:Acetylcholine / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D008297:Male; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000187:drug effects*; D012701:Serotonin / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000378:metabolism / Q000494:pharmacology
chemical_list: D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D012701:Serotonin; D000109:Acetylcholine; D011188:Potassium