Ergotamine (EG)

Ergotamine is an ergopeptine and part of the ergot family of alkaloids; it is structurally and biochemically closely related to ergoline. It possesses structural similarity to several neurotransmitters, and has biological activity as a vasoconstrictor. The mechanism of action of ergotamine is complex.

The molecule shares structural similarity with neurotransmitters such as serotonin, dopamine, and epinephrine and can thus bind to several receptors acting as an agonist. The anti-migraine effect is due to constriction of the intracranial extracerebral blood vessels through the 5-HT1B receptor, and by inhibiting trigeminal neurotransmission by 5-HT1D receptors. Ergotamine also has effects on the dopamine and norepinephrine receptors. Its side effects are due mainly to its action at the D2 dopamine and 5-HT1A receptors.