ergotamine brands

Molecular formula: C33H35N5O5

Ergotamine acts on migraine by one of two proposed mechanisms: 1) activation of 5-HT_1D receptors located on intracranial blood vessels, including those on arterio-venous anastomoses, leads to vasoconstriction, which correlates with the relief of migraine headache, and 2) activation of 5-HT_1D receptors on sensory nerve endings of the trigeminal system results in the inhibition of pro-inflammatory neuropeptide release. Ergotamine has complex pharmacologic effects. In therapeutic doses, ergotamine causes peripheral vasoconstriction (if the vascular tone is low) primarily by stimulating alpha-adrenergic receptors; however, the drug causes vasodilation in very hypertonic vessels. With higher doses, ergotamine is also a competitive alpha-adrenergic blocker, but this effect is somewhat masked by the drug's alpha-adrenergic agonist activity. With therapeutic doses, ergotamine also inhibits reuptake of norepinephrine, thereby maintaining a high concentration of circulating norepinephrine and increasing ergotamine's vasoconstrictor action. Ergotamine has greater vasoconstrictor activity than the other ergot alkaloids but less alpha-adrenergic blocking activity than dihydroergotamine. Ergotamine is a weaker antagonist of serotonin (5-hydroxytryptamine) than is methysergide, but ergotamine does reduce the increased rate of platelet aggregation induced by serotonin. The mechanism by which ergotamine aborts vascular headaches is probably direct vasoconstriction of the dilated carotid artery bed with a concomitant decrease in the amplitude of pulsations; the drug's effects on catecholamines and serotonin are also at least partly involved. Sumatriptan, dihydroergotamine and methysergide inhibit 1% formalin-induced nociception by activation of peripheral 5-HT1B/1D receptors. This study set out to investigate the pharmacological profile of the antinociception produced by intrathecal and intraplantar administration of ergotamine (a 5-HT1B/1D and 5-HT5A/5B receptor agonist) and valerenic acid (a partial agonist at 5-HT5A receptors). Intraplantar injection of 1% formalin in the right hind paw resulted in spontaneous flinching behavior of the injected hindpaw of female Wistar rats. Intrathecal ergotamine (15 nmol) or valerenic acid (1 nmol) blocked in a dose dependent manner formalin-induced nociception. The antinociception by intrathecal ergotamine (15 nmol) or valerenic acid (1 nmol) was partly or completely blocked by intrathecal administration of the antagonists: (i) methiothepin (non-selective 5-HT5A/5B; 0.01-0.1 nmol); (ii) SB-699551 (selective 5-HT5A; up to 10 nmol); (iii) anti-5-HT5A antibody; (iv) SB-224289 (selective 5-HT1B; 0.1-1 nmol); or (v) BRL-15572 (selective 5-HT1D; 0.1-1 nmol). Likewise, antinociception by intraplantar ergotamine (15 nmol) and valerenic acid (10 nmol) was: (i) partially blocked by methiothepin (1 nmol), SB-699551 (10 nmol) or SB-224289 (1 nmol); and (ii) abolished by BRL-15572 (1 nmol). The above doses of antagonists (which did not affect per se the formalin-induced nociception) were high enough to completely block their respective receptors. Our results suggest that ergotamine and valerenic acid produce antinociception via 5-HT5A and 5-HT1B/1D receptors located at both spinal and peripheral sites. This provides new evidence for understanding the modulation of nociceptive pathways in inflammatory pain. It has previously been suggested that ergotamine produces external carotid vasoconstriction in vagosympathectomised dogs via 5-HT1B/1D receptors and alpha2-adrenoceptors. The present study has reanalyzed this suggestion by using more selective antagonists alone and in combination. Fifty-two anesthetized dogs were prepared for ultrasonic measurements of external carotid blood flow. The animals were divided into thirteen groups (n=4 each) receiving an i.v. bolus injection of, either physiological saline (0.3 mL/kg; control), or the antagonists SB224289 (300 ug/kg; 5-HT1B), BRL15572 (300 ug /kg; 5

Source: PubChem (NCBI) · compound 8223