Ergotamine: 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.Dihydroergotamine: A 9,10alpha-dihydro derivative of ERGOTAMINE. It is used as a vasoconstrictor, specifically for the therapy of MIGRAINE DISORDERS.Ergotamines: A series of structurally-related alkaloids containing the ergotaman backbone structure.Ergotism: Poisoning caused by ingesting ergotized grain or by the misdirected or excessive use of ergot as a medicine.Ergonovine: An ergot alkaloid (ERGOT ALKALOIDS) with uterine and VASCULAR SMOOTH MUSCLE contractile properties.Arteriovenous Anastomosis: A vessel that directly interconnects an artery and a vein, and that acts as a shunt to bypass the capillary bed. Not to be confused with surgical anastomosis, nor with arteriovenous fistula.Dihydroergocornine: A 9,10alpha-dihydro derivative of ERGOTAMINE that contains isopropyl sidechains at the 2' and 5' positions of the molecule.Migraine Disorders: A class of disabling primary headache disorders, characterized by recurrent unilateral pulsatile headaches. The two major subtypes are common migraine (without aura) and classic migraine (with aura or neurological symptoms). (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)Sumatriptan: A serotonin agonist that acts selectively at 5HT1 receptors. It is used in the treatment of MIGRAINE DISORDERS.Ergot Alkaloids: Alkaloids originally isolated from the ergot fungus Claviceps purpurea (Hypocreaceae). They include compounds that are structurally related to ergoline (ERGOLINES) and ergotamine (ERGOTAMINES). Many of the ergot alkaloids act as alpha-adrenergic antagonists.Suppositories: Medicated dosage forms that are designed to be inserted into the rectal, vaginal, or urethral orifice of the body for absorption. Generally, the active ingredients are packaged in dosage forms containing fatty bases such as cocoa butter, hydrogenated oil, or glycerogelatin that are solid at room temperature but melt or dissolve at body temperature.Ergolines: A series of structurally-related alkaloids that contain the ergoline backbone structure.Dibenzylchlorethamine: An alpha adrenergic antagonist.Methysergide: An ergot derivative that is a congener of LYSERGIC ACID DIETHYLAMIDE. It antagonizes the effects of serotonin in blood vessels and gastrointestinal smooth muscle, but has few of the properties of other ergot alkaloids. Methysergide is used prophylactically in migraine and other vascular headaches and to antagonize serotonin in the carcinoid syndrome.Methiothepin: A serotonin receptor antagonist in the CENTRAL NERVOUS SYSTEM used as an antipsychotic.Moxisylyte: An alpha-adrenergic blocking agent that is used in Raynaud's disease. It is also used locally in the eye to reverse the mydriasis caused by phenylephrine and other sympathomimetic agents. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1312)Receptors, Serotonin: Cell-surface proteins that bind SEROTONIN and trigger intracellular changes which influence the behavior of cells. Several types of serotonin receptors have been recognized which differ in their pharmacology, molecular biology, and mode of action.Vasoconstrictor Agents: Drugs used to cause constriction of the blood vessels.