The effects of volatile anesthetics on recombinant adenosine triphosphate-sensitive potassium channels

背景：最近的证据表明，在生理和病理生理条件下，血管平滑肌细胞上的三磷酸腺苷敏感钾(K&lt；ATP&gt；)通道在调节血管紧张性方面起着关键作用。对挥发性麻醉药与血管K_1、K_1、ATP、G_(T)通道相互作用的研究一直很有限。方法：采用细胞贴壁法和膜片钳技术，对天然血管钾通道和由内向整流钾通道亚基(Kir6)组成的重组钾通道进行电生理实验。1)和磺酰脲受体(SUR2B)。结果：在细胞贴壁记录过程中，在浴液中加入0.5 mM的异氟醚可显著增加K_…。More-lt；ATP&gt；通道活性被选择性蛋白激酶A(PKA)、RP-cAMP(100μM)预处理后显著降低。在由内向外的贴片中，异氟醚不能激活K&lt；ATP；通道。异氟醚可显著激活细胞贴片上的野生型重组SUR2B/Kir6.1。在PKA不敏感突变体SUR2B-T633A/Kir6.1、SUR2B-S1465A/Kir6中，异氟醚对野生型通道的激活作用减弱。和SUR2B/Kir6.1-S385A。此外，我们还证实了异氟烷诱导的PKA激活与异氟烷引起的大鼠主动脉等长张力降低有关。结论：异氟醚通过激活PKA激活K&lt；ATP&gt；通道。在等长张力实验中，也观察到异氟醚对PKA依赖的血管扩张作用。对表达的血管类型K_lt；ATP&gt；通道的分析表明，PKA介导的Kir6.1和SUR2B亚基的磷酸化在异氟醚诱导的血管K_&lt；ATP&gt；通道激活中起着关键作用。较少

Background ; Recent evidence indicates that vascular adenosine triphosphate-sensitive potassium (K_<ATP>) channels in vascular smooth muscle cells are critical in the regulation of vascular tonus under both physiological and pathophysiological conditions. Studies of the interaction of volatile anesthetics with vascular K_<ATP> channels have been limited. In the present study, we investigated the molecular mechanism of isoflurane's action on vascular K_<ATP> channels.Methods ; Electrophysiologic experiments were performed using cell-attached and inside-out patch-clamp techniques to monitor native vascular K_<ATP> channels, and recombinant K_<ATP> channels comprised of inwardly rectifying potassium, channel subunits (Kir6. 1) and the sulfonylurea receptor (SUR2B). Isometric tension experiments were performed in rat thoracic aortic rings without endothelium.Results ; Application of isoflurane (0.5mM) to the bath solution during cell-attached recordings induced a significant increase in K_ … More <ATP> channel activity, which was greatly reduced by pretreatment with a selective inhibitor protein kinase A (PKA), Rp-cAMPS (100 μM). In inside-out patches, isoflurane failed to activate K_<ATP> channels. Isoflurane significantly activated wild type recombinant SUR2B/Kir6.1 in cell-attached patches. Isoflurane-induced activation of wild-type channels was diminished in the PKA-insensitive mutant SUR2B-T633A/Kir6.1, SUR2B-S1465A/Kir6. 1, and SUR2B/Kir6.1-S385A. In addition, we demonstrated that isoflurane-induced PKA activation was associated with isoflurane-induced decreases in isometric tension in the rat aorta.Conclusion ; Our results indicated that isoflurane activates K_<ATP> channels via PKA activation. PKA-dependent vasodilation induced by isoflurane also was observed in isometric tension experiments. Analysis of expressed vascular type K_<ATP>, channels suggested that PKA-mediated phosphorylation of both Kir6.1 and SUR2B subunits plays a pivotal role in isoflurane-induced vascular K_<ATP>, channel activation. Less