Muscarinic suppression of ATP-sensitive K+ channels mediated by the M3/Gq/11/phospholipase C pathway contributes to mouse ileal smooth muscle contractions
| العنوان: | Muscarinic suppression of ATP-sensitive K+ channels mediated by the M3/Gq/11/phospholipase C pathway contributes to mouse ileal smooth muscle contractions |
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| المؤلفون: | Maiki Ono, Hayato Matsuyama, Saki Fujikawa, Ban Wang, Yasuyuki Tanahashi, Yuri Murakami, Toshihiro Unno, Kiyotada Naitou |
| المصدر: | American Journal of Physiology-Gastrointestinal and Liver Physiology. 315:G618-G630 |
| بيانات النشر: | American Physiological Society, 2018. |
| سنة النشر: | 2018 |
| مصطلحات موضوعية: | 0301 basic medicine, Hepatology, Phospholipase C, Physiology, Chemistry, Gastroenterology, Muscarinic acetylcholine receptor M3, Cell biology, 03 medical and health sciences, 030104 developmental biology, 0302 clinical medicine, Smooth muscle, Physiology (medical), Muscarinic acetylcholine receptor, Knockout mouse, Atp sensitive k channel, 030217 neurology & neurosurgery, K channels |
| الوصف: | ATP-sensitive K+ (KATP) channels are expressed in gastrointestinal smooth muscles, and their activity is regulated by muscarinic receptor stimulation. However, the physiological significance and mechanisms of muscarinic regulation of KATP channels are not fully understood. We examined the effects of the KATP channel opener cromakalim and the KATP channel blocker glibenclamide on electrical activity of single mouse ileal myocytes and on mechanical activity in ileal segment preparations. To explore muscarinic regulation of KATP channel activity and its underlying mechanisms, the effect of carbachol (CCh) on cromakalim-induced KATP channel currents ( IKATP) was studied in myocytes of M2 or M3 muscarinic receptor-knockout (KO) and wild-type (WT) mice. Cromakalim (10 µM) induced membrane hyperpolarization in single myocytes and relaxation in segment preparations from WT mice, whereas glibenclamide (10 µM) caused membrane depolarization and contraction. CCh (100 µM) induced sustained suppression of IKATP in cells from both WT and M2KO mice. However, CCh had a minimal effect on IKATP in M3KO and M2/M3 double-KO cells. The Gq/11 inhibitor YM-254890 (10 μM) and PLC inhibitor U73122 (1 μM), but not the PKC inhibitor calphostin C (1 μM), markedly decreased CCh-induced suppression of IKATP in WT cells. These results indicated that KATP channels are constitutively active and contribute to the setting of resting membrane potential in mouse ileal smooth muscles. M3 receptors inhibit the activity of these channels via a Gq/11/PLC-dependent but PKC-independent pathways, thereby contributing to membrane depolarization and contraction of smooth muscles. NEW & NOTEWORTHY We systematically investigated the regulation of ATP-sensitive K+ channels by muscarinic receptors expressed on mouse ileal smooth muscles. We found that M3 receptors inhibit the activity of ATP-sensitive K+ channels via a Gq/11/PLC-dependent, but PKC-independent, pathway. This muscarinic suppression of ATP-sensitive K+ channels contributes to membrane depolarization and contraction of smooth muscles. |
| تدمد: | 1522-1547 0193-1857 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_________::1765add6ec08521d7c2b8ace1deb6fb7Test https://doi.org/10.1152/ajpgi.00069.2018Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi...........1765add6ec08521d7c2b8ace1deb6fb7 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 15221547 01931857 |
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