Consequences of metabolic inhibition in smooth muscle isolated from guinea‐pig stomach
Consequences of metabolic inhibition in smooth muscle isolated from guinea‐pig stomach
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豚鼠胃平滑肌代谢抑制的后果
DOI：
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Tadao Tomita
中科院分区：
文献类型：
--
作者：
Shinsuke Nakayama;S. Chihara;Joseph F. Clark;S.‐M. Huang;T. Horrachi;Tadao Tomita
1用氰化物(CN)和碘乙酸(IAA)分别阻断氧化磷酸化和糖酵解。通过与CN的比较，系统地研究了IAA对自发机械和电活动产生的影响。在施加1 mM IAA期间，自发活动在10-20分钟内停止。而施加1 mM CN也可减少自发活动，但并未使其停止。在CN存在下，静息膜电位的负性略有降低。2当IAA使自发活动停止时，静息膜电位无明显变化。停药前自发性电活动的波幅和持续时间均显著降低。然而，IAA不改变电紧张性电位的幅度。此外，格列本脲不能阻止IAA的作用。这些结果表明，与心肌不同，胃平滑肌代谢依赖性K+通道的激活似乎不是代谢抑制时减少和终止自发活动的主要作用。3应用IAA时，卡巴胆碱引起的收缩一过性增加，随后逐渐减少。4IAA作用50min后，在没有自发活动的情况下，31P核磁共振测得的磷酸肌酸和三磷酸腺苷浓度分别下降到对照组的60%和80%，而无机磷浓度则相反地下降到检测到的水平以下。在随后的长时间应用IAA期间，高能磷酸盐稳步下降。而在CN处理50min后，[PCr]和[ATP]分别下降到对照的30%和80%左右，而[PI]则增加了2.6倍。5在CN或IAA存在的情况下，自发的机械和电活动减少或消除，但仍有足够收缩平滑肌的高能磷酸盐存在。可以推测，与能量代谢有关的某些机制(S)，而不包括三磷酸腺苷敏感的钾通道，在豚鼠胃平滑肌自发活动的产生中起重要作用。在代谢抑制期间，能量代谢依赖机制(S)将通过停止自发活动来保护高能磷酸盐，从而保持细胞活力。
1 In smooth muscle isolated from the guinea‐pig stomach, cyanide (CN) and iodoacetic acid (IAA) were applied to block oxidative phosphorylation and glycolysis, respectively. Effects of IAA on generation of spontaneous mechanical and electrical activities were systematically investigated by comparing those of CN. Spontaneous activity ceased in 10–20 min during applications of 1 mm IAA. On the other hand, application of 1 mm CN also reduced the spontaneous activity, but never terminated it. In the presence of CN the negativity of the resting membrane potential was slightly reduced. 2 When spontaneous activity ceased with IAA, the resting membrane potential was not significantly affected. Also, before ceasing, the amplitude and duration of the spontaneous electrical activity were significantly reduced. The amplitude of the electrotonic potential was, however, not changed by IAA. Further, glibenclamide did not prevent the effects of IAA. These results suggest that, unlike cardiac muscle, activation of metabolism‐dependent K+ channels in stomach smooth muscle does not seem to play a major role in reducing and terminating spontaneous activity during metabolic inhibition. 3 Carbachol‐induced contraction transiently increased, and subsequently decreased gradually during application of IAA. 4 After 50 min application of IAA, when there was no spontaneous activity, the concentrations of phosphocreatine (PCr) and ATP measured with 31P nuclear magnetic resonance decreased to 60 and 80% of the control, respectively, while inorganic phosphate (Pi) concentration paradoxically fell to below detectable levels. During subsequent prolonged application of IAA, high‐energy phosphates steadily decreased. On the other hand, after 50 min CN application, [PCr] and [ATP] decreased to approximately 30 and 80% of the control, respectively, while [Pi] increased by 2.6‐fold. 5 In the presence of either CN or IAA, spontaneous mechanical and electrical activities were reduced or eliminated, although amounts of high‐energy phosphates sufficient to contract smooth muscle remained. It can be postulated that some mechanism(s) related to energy metabolism, but not including ATP‐sensitive K+ channels, plays an important role in generating spontaneous activity in guinea‐pig stomach smooth muscle. During metabolic inhibition the energy metabolism‐dependent mechanism(s) would preserve high‐energy phosphates, and consequently cell viability, by stopping spontaneous activity.
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影响因子：
18.2
作者：
T. Butler;M. J. Siegman
通讯作者：
T. Butler;M. J. Siegman
影响因子：
20.1
作者：
NICHOLS, CG;RIPOLL, C;LEDERER, WJ
通讯作者：
LEDERER, WJ
DOI：
10.1016/s0021-9258(18)66886-3
发表时间：
1986-11
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
M. Kushmerick;P. Dillon;R. Meyer;T. Brown;J M Krisanda;H. Sweeney
通讯作者：
M. Kushmerick;P. Dillon;R. Meyer;T. Brown;J M Krisanda;H. Sweeney
绵羊主动脉对磷酸肌酸、无机磷酸盐和 ATP 同时降低的张力反应。
DOI：
10.1113/jphysiol.1992.sp019410
发表时间：
1992
期刊：
The Journal of physiology
影响因子：
--
作者：
Hardin,CD;Wiseman,RW;Kushmerick,MJ
通讯作者：
Kushmerick,MJ
影响因子：
--
作者：
PAUL, RJ
通讯作者：
PAUL, RJ