Presynaptic 5-hydroxytryptamine receptors modulating noradrenaline release in bovine cerebral arteries

The electrical stimulation of bovine cerebral arteries preincubated with [ super(3)H]-noradrenaline (NA) evoked tritium overflow, which was reduced by tetrodotoxin, Ca super(2+)-free medium and denervation by pretreatment with 6-hydroxydopamine. The evoked tritium overflow was reduced by non-selective, 5-hydroxytryptamine (5-HT), and selective, 5-carboxamidotryptamine (5-CT) and sumatriptan, agonists of 5-HT sub(1)-like receptors, the latter with certain preference for the 5-HT sub(1D) subtype. The results suggest: the evoked NA release is modulated by 5-HT sub(1)-like receptors, likely to be of 5-HT sub(1D) subtype; and metitepine has also the ability to block NA uptake and to antagonize presynaptic alpha sub(2)-adrenoceptors.