5-hydroxytryptamine: its facilitative action on [3H]dopamine release from the retina.
5-Hydroxytryptamine (5-HT) at 5 X 10(-4) M caused a two-fold increase in [3H]dopamine (DA) release from retinal particulate fractions of the carp (Cyprinus carpio). The 5-HT action was dose- and Ca2+-dependent. The three 5-HT agonists examined (5-methoxytryptamine, 5-methoxy-N,N-dimethyltryptamine and tryptamine) were more effective than 5-HT on [3H]DA release. 5,6-Dihydroxytryptamine was the strongest competitor among drugs tested for [3H ]DA uptake, but did not evoke any significant release of [3H]DA. Noradrenaline (or DA) at 5 X 10(-4) M produced a large increase in [3H]DA release from the particulate fractions, but its action was Ca2+-independent. The 5-HT-induced DA release could be seen in the frog retina but not in the rat retina, which does not contain indoleamine-accumulating cells. The results obtained strongly suggest that 5-HT stimulates [3H ]DA release through a receptor mechanism on DAergic terminals and modifies the DA-cell's function in the retina.
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002347:Carps / Q000378:metabolism*; D003530:Cyprinidae / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D066298:In Vitro Techniques; D009638:Norepinephrine / Q000494:pharmacology; D012160:Retina / Q000187:drug effects / Q000378:metabolism*; D012701:Serotonin / Q000494:pharmacology*; D013045:Species Specificity; D014363:Tryptamines / Q000494:pharmacology
D014363:Tryptamines; D012701:Serotonin; C030820:tryptamine; D002118:Calcium; D004298:Dopamine; D009638:Norepinephrine