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. Ergotamine is a secondary metabolite (natural product) and the principal alkaloid produced by the ergot fungus, Claviceps purpurea, and related fungi in the family Clavicipitaceae. It was first isolated from the ergot fungus by Arthur Stoll at Sandoz in 1918 and marketed as Gynergen in 1921

it is used medicinally for treatment of acute migraine attacks (sometimes in combination with caffeine). Medicinal usage of ergot fungus began in the 16th century to induce childbirth, yet dosage uncertainties discouraged the use. It has been used to prevent post-partum hemorrhage (bleeding after childbirth).

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.

Formal Chemical Name (IUPAC)
(8β)-N-[(2R,5S,10aS,10bS)-5-Benzyl-10b-hydroxy-2-methyl-3,6-dioxooctahydro-8H-[1,3]oxazolo[3,2-a]pyrrolo[2,1-c]pyrazin-2-yl]-6-methyl-9,10-didehydroergoline-8-carboximidic acid

References

https://en.wikipedia.org/wiki/Ergotamine