Pre-synaptic Sympathetic Inhibition and 5-Hydroxytryptamine-induced Vasodilatation

Within 5 years of the isolation of the serum vasoconstrictor factor, 5-hydroxytryptamine (5-HT), its vasodilating properties had been recognized; Haddy (1953) described 5-HT-induced vasodilation in the forelimb in anaesthetized dogs. A real understanding of the mechanisms responsible for the vasodilator effects of 5-HT, however, has taken a much longer time to emerge.