Receptors involved in the modulation of 5-hydroxytryptamine release in bovine cerebral arteries

The uptake of [3H]5-hydroxytryptamine (5-HT) in bovine cerebral arteries was reduced by cocaine (1 microM), ouabain (100 microM), pretreatment with 6-hydroxydopamine (6-OHDA) (1.46 mM, 10 min) and metitepine (1 microM). Electrically-stimulated tritium release was decreased by tetrodotoxin (0.8 microM), Ca-free medium, denervation with 6-OHDA (1.46 mM, 10 min), 5-HT (10 microM), noradrenaline (1 microM) and the agonist of alpha 2-adrenoceptors B-HT 920 (0.1 and 1 microM), enhanced by metitepine (1 microM, antagonists of presynaptic 5-HT1 receptors) and rauwolscine (1 microM, antagonist at alpha 2-adrenoceptors, and also of 5-HT1D receptors) and not affected by ketanserin (1 microM, antagonist of 5-HT2 receptors), methysergide (0.1 microM, antagonist of 5-HT1 and 5-HT2 receptors) and phentolamine (1 and 3 microM antagonist of alpha-adrenoceptors and less potent of 5-HT1 receptors). The inhibitory action of 10 microM 5-HT was partially reversed by phentolamine (3 microM) and cocaine (1 microM) and completely reversed by both metitepine (1 microM) and rauwolscine (1 microM). Ketanserin (1 microM), methysergide (0.1 microM) or phentolamine (1 microM) had no effect. Rauwolscine (1 microM) antagonized the inhibition induced by both noradrenaline (1 microM) and B-HT 920 (0.1 and 1 microM). 5-HT induced tritium release which was inhibited by cocaine (an antagonist of 5-HT3 receptors) and denervation with 6-OHDA.(ABSTRACT TRUNCATED AT 250 WORDS)