| 14744615 |
Villalon CM, Centurion D, Willems EW, Arulmani U, Saxena PR, Valdivia LF: 5-HT1B receptors and alpha 2A/2C-adrenoceptors mediate external carotid vasoconstriction to dihydroergotamine. Eur J Pharmacol. 2004 Jan 26;484(2-3):287-90.
Dihydroergotamine produces external carotid vasoconstriction in vagosympathectomized dogs by 5-HT (1B/1D) receptors and alpha (2)-adrenoceptors. This study identified the specific subtypes involved in this response. One-minute intracarotid infusions of dihydroergotamine (5.6-10 microg/min) dose-dependently decreased external carotid blood flow without affecting blood pressure or heart rate. This response was: (1) partly blocked in dogs pretreated intravenously with the antagonists SB224289 (5-HT (1B); 2,3,6,7-tetrahydro-1'-methyl-5-[2'-methyl-4' (5-methyl-1,2,4-oxadiazol-3-yl) biphenyl-4-carbonyl] furo [2,3-f] indole-3-spi ro-4'-piperidine hydrochloride), rauwolscine (alpha (2)), BRL44408 (alpha (2A); 2-[2H-(1-methyl-1,3-dihydroisoindole) methyl]-4,5-dihydroimidazole) or MK912 (alpha (2C); (2S,12bS)-1'3'-dimethylspiro (1,3,4,5',6,6',7,12b-octahydro-2Hbenzo [b] furo [ 2,3-a] quinazoline)-2,4'-pyrimidin-2'-one); (2) markedly blocked after SB224289 plus rauwolscine; and (3) unaffected after BRL15572 (5-HT (1D); 1-(3-chlorophenyl)-4-[3,3-diphenyl (2-(S,R) hydroxypropanyl) piperazine] hydrochloride) or imiloxan (alpha (2B)). Therefore, the above response involves 5-HT (1B) receptors and alpha (2A/2C)-adrenoceptors. |
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