A naturally occurring ergot alkaloid with vasoconstrictor and analgesic property. Ergotamine selectively binds and activates serotonin (5-HT) 1D receptors located on intracranial blood vessels, including those on arterio-venous anastomoses, thereby resulting in vasoconstriction and reducing the blood flow in cerebral arteries that may lead to relieve of vascular headaches. This agent also selectively binds to alpha-adrenergic receptors, thereby stimulating vascular smooth muscle and causing vasoconstriction in both arteries and veins, which also contributes to the relief of headaches. Furthermore, the activation of 5-HT1D receptors on sensory nerve endings of the trigeminal system results in the inhibition of pro-inflammatory neuropeptide release.

A vasoconstrictor found in ergot of Central Europe. It is a serotonin agonist that has been used as an oxytocic agent and in the treatment of MIGRAINE DISORDERS.