Muscarinic suppression of ATP-sensitive K+ channel in rabbit esophageal smooth muscle.
Muscarinic suppression of ATP-sensitive K+ channel in rabbit esophageal smooth muscle.
复制标题
毒蕈碱抑制兔食管平滑肌中 ATP 敏感 K 通道。
DOI：
10.1152/ajpcell.1995.268.4.c877
复制
发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Akbarali,HI
中科院分区：
文献类型：
--
作者：
Hatakeyama,N;Wang,Q;Goyal,RK;Akbarali,HI
本实验研究了兔食管肌层平滑肌细胞是否存在ATP敏感性钾通道(KATP)及氨基甲胆碱对该通道的抑制作用。钾通道开放剂利马卡林(10微米)使细胞内电流增加-174+/-15 pA(细胞内ATP浓度为0.1 mM)，使全细胞电流增加-70+/-11 pA(5 mM[ATP]i)，格列本脲(10微米)完全阻断利马卡林诱导的电流。因此，这些电流被表示为KATP。细胞内10 mM乙二醇双(β-氨基乙基醚)-N，N，N‘，N’-四乙酸乙酯(EGTA)浓度为10 mM时，卡巴胆碱对KATP的抑制率为74+/-4%，而不加EGTA时，抑制率为100%。M3受体拮抗剂p-氟六氢西拉非尼多(0.1微米)可使卡巴胆碱抑制减弱至23+/-16%。佛波醇12-肉豆蔻酸酯13-乙酸酯(PMA；100 nM)对KATP的抑制作用为63+/-9%。蛋白激酶C和酪氨酸激酶的抑制剂可显著降低PMA和卡巴胆碱的作用。这些结果表明，卡巴胆碱对KATP的抑制作用是通过M3受体亚型实现的，信号通路涉及钙离子、蛋白激酶C和酪氨酸激酶。
Smooth muscle cells from the rabbit esophageal muscularis mucosae were studied for the presence of ATP-sensitive K+ channel (KATP) and its inhibition by carbachol. Lemakalim (10 microM), a synthetic K+ channel opener, increased whole cell currents by -174 +/- 15 pA with 0.1 mM intracellular ATP concentration ([ATP]i) and -70 +/- 11 pA with 5 mM [ATP]i. Glibenclamide (10 microM) completely abolished the lemakalim-induced currents. These currents were therefore denoted as KATP. Carbachol (10 microM) suppressed KATP by 74 +/- 4% with 10 mM intracellular ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) concentration and 100% when EGTA was omitted from the pipette solution. Carbachol suppression was attenuated to 23 +/- 16% by the M3 receptor antagonist, p-flurohexahydrosiladifenidol (0.1 microM). KATP was also suppressed by phorbol 12-myristate 13-acetate (PMA; 100 nM) by 63 +/- 9%. The effects of both PMA and carbachol were significantly reduced by inhibitors of protein kinase C and tyrosine kinase. These results suggest that carbachol suppression of KATP is via M3 receptor subtype and the signaling pathway involves Ca2+, protein kinase C, and tyrosine kinase.