Isoproterenol attenuates myosin phosphorylation and contraction of tracheal muscle.
Isoproterenol attenuates myosin phosphorylation and contraction of tracheal muscle.
复制标题
异丙肾上腺素减弱肌球蛋白磷酸化和气管肌肉的收缩。
DOI：
10.1152/jappl.1989.66.5.2017
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
deLanerolle,P
中科院分区：
文献类型：
--
作者：
Obara,K;deLanerolle,P
在离体羊气管平滑肌细肌束（直径0.1- 0.2mm）上，观察了异丙肾上腺素对等长收缩力、无负荷缩短速度和肌球蛋白磷酸化的影响。乙酰甲胆碱（10（-6）M）诱导等长收缩力和20，000-Da肌球蛋白轻链磷酸化的快速增加。肌球蛋白磷酸化在等长收缩力的稳态维持过程中保持升高。缩短速度达到峰值后15秒，乙酰甲胆碱刺激，然后下降到约45%的最大值3分钟。异丙肾上腺素预处理抑制乙酰甲胆碱刺激的肌球蛋白轻链磷酸化，缩短速度，和力的早期阶段的力量产生。然而，异丙肾上腺素对力和肌球蛋白磷酸化的抑制作用比对缩短速度的抑制作用大。异丙肾上腺素预处理也引起乙酰甲胆碱剂量-反应曲线的等距张力和肌球蛋白轻链磷酸化的非平行移动。这些数据表明，异丙肾上腺素通过影响肌球蛋白轻链磷酸化的速率和程度来减弱气道平滑肌的收缩特性，可能是通过涉及肌球蛋白轻链激酶磷酸化和Ca 2+代谢的协同相互作用的机制。
The effects of isoproterenol on isometric force, unloaded shortening velocity, and myosin phosphorylation were examined in thin muscle bundles (0.1–0.2 mm diam) dissected from lamb tracheal smooth muscle. Methacholine (10(-6) M) induced rapid increases in isometric force and in phosphorylation of the 20,000-Da myosin light chain. Myosin phosphorylation remained elevated during steady-state maintenance of isometric force. The shortening velocity peaked at 15 s after stimulation with methacholine and then declined to approximately 45% of the maximal value by 3 min. Isoproterenol pretreatment inhibited methacholine-stimulated myosin light chain phosphorylation, shortening velocity, and force during the early stages of force generation. However, the inhibitory effect of isoproterenol on force and myosin phosphorylation is proportionally greater than that on shortening velocity. Isoproterenol pretreatment also caused a rightward non-parallel shift in the methacholine dose-response curves for both isometric tension and myosin light chain phosphorylation. These data demonstrate that isoproterenol attenuates the contractile properties of airway smooth muscles by affecting the rate and extent of myosin light chain phosphorylation, perhaps through a mechanism that involves the synergistic interaction of myosin light chain kinase phosphorylation and Ca2+ metabolism.