- 著者
- Masatoshi OKUBO Yoh-ichi SATOH Masato HIRAKAWA Kana SASAKI Kazuki MASU Gabriel J. MCHONDE Chika IKEDA-KUROSAWA Daijiro KUROSAKA Tomoyuki SAINO
- 出版者
- Biomedical Research Press
- 雑誌
- Biomedical Research (ISSN:03886107)
- 巻号頁・発行日
- vol.37, no.2, pp.101-115, 2016-04-01 (Released:2016-04-23)
- 参考文献数
- 87
- 被引用文献数
- 3 3
5-hydroxytriptamine (5-HT: serotonin) is an important transmitter that causes vessel constriction, although few studies have examined the effect of 5-HT on venous smooth muscles. The intracellular Ca2+ concentration ([Ca2+]i) plays an essential role in stimulus-response coupling in numerous tissue/cells including vascular smooth muscle cells. The present study was performed to examine whether differences between arteries and veins in the response to 5-HT can be detected under confocal microscope with respect to [Ca2+]i dynamics. In posterior ciliary arteries of rats, 5-HT induced a [Ca2+]i increase. The 5-HT-induced responses were caused by both Ca2+ influx and mobilization. Agonist and antagonist experiments revealed that arterial smooth muscles possess 5-HT1a, 1b, 2 (Gprotein-coupled type) and 5-HT3 (ion channel type) receptors, and that 5-HT2 in particular plays a major role in these responses. For vorticose veins, the 5-HT-induced responses were also caused by both Ca2+ influx and mobilization. However, the cAMP dependent pathway (5-HT4-7) was found to be significant in vasocontraction with respect to 5-HT in these vessels. Thus, Ca2+ mobilization was induced by 5-HT2 and 5-HT4-7 in a vessel-dependent manner, whereas Ca2+ influx universally was induced by 5-HT3. These results indicate that the posterior ciliary arteries and vorticose veins in the same tissue might differ greatly in their responses to stimulus.