Functional serotonin and histamine receptor subtypes in porcine ciliary artery in comparison with middle cerebral artery

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• 作者：Shingo Nagai ; Tatsuru Tsurumaki ; Haruki Abe ; Hiroshi Higuchi
• 关键词：Serotonin ; Histamine ; Middle cerebral artery ; Ciliary artery ; Receptor
• 刊名：European Journal of Pharmacology
• 出版年：2007
• 出版时间：10 September 2007
• 年：2007
• 卷：570
• 期：1-3
• 页码：159-166
• 全文大小：346 K

文摘

Functional serotonin (5-HT) and histamine receptor subtypes were investigated in porcine middle cerebral and ciliary arteries. An H₁ antagonist, mepyramine, antagonized histamine-induced responses with pK_B values of 8.91–9.10. In the presence of 1 μM mepyramine, however, histamine caused dilation through H₂ receptors in the middle cerebral but not in the ciliary artery. A 5-HT_2A antagonist, ketanserin, antagonized 5-HT-induced responses, causing rightward shifts in the concentration–response curves with pK_B values of 8.52–8.71. A 5-HT_1B antagonist, SB224289, produced rightward shifts of the concentration–response curves to sumatriptan with pK_B values (6.66) only in the middle cerebral artery. In contrast, a 5-HT_1D antagonist, BRL15572, had no effect in either artery. An RT-PCR study demonstrated the gene expression of the mRNAs of all three receptors (5HT_1B, 5HT_1D and 5HT_2A) in both arteries. These results suggest that histamine-induced contraction is mediated only through functional H₁ receptor in these arteries. Interestingly, there are functional 5-HT_2A and 5-HT_1B receptor subtypes in the middle cerebral artery, whereas the only functional receptor is 5-HT_2A in the ciliary artery. The difference may be important for treatment with 5-HT_1B/1D agonists (e.g. for migraine) without ocular side effect.