Characterization of the 5-hydroxytryptamine receptor which mediates contraction of the human isolated basilar artery.
This paper reports part of a study which investigated the identity of the receptor involved in 5-hydroxytryptamine (5-HT) mediated contraction of the human basilar artery in vitro. 5-HT and a variety of 5-HT receptor agonists contracted human isolated basilar artery with a rank order of agonist potency: 5-carboxamidotryptamine greater than 5-HT greater than GR43175 much much greater than 2-methyl-5-HT. The maximum response produced by these agonists differed. The contractile responses to both 5-HT and GR43175 were resistant to antagonism by the 5-HT2 antagonist ketanserin and the 5-HT3 antagonist GR38032, indicating that neither 5-HT nor GR43175 activate 5-HT2 and 5-HT3 receptors in this tissue. In striking contrast, methiothepin (an antagonist at 5-HT1-like receptors) proved a potent antagonist of the contractile actions of both 5-HT and GR43175. Methiothepin did not antagonize the contractile response to the thromboxane-A2 mimetic U-46619. It is concluded that 5-HT and GR43175 contract the human isolated basilar artery by activating 5-HT1-like receptors. It is suggested that the antimigraine action of GR43175 may reflect its ability to constrict certain cranial arteries via 5-HT1-like receptor activation.
Parsons
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Department of Physiological Sciences, University of Manchester, UK.
Whalley
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D001488:Basilar Artery / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007211:Indoles / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000031:analogs & derivatives / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology; D018170:Sumatriptan
D007211:Indoles; D011985:Receptors, Serotonin; D013449:Sulfonamides; D012701:Serotonin; D018170:Sumatriptan; C047087:5-carboxamidotryptamine