Contractile proteins in myocardial cells are regulated by factor(s) released by blood vessels.
Contractile proteins in myocardial cells are regulated by factor(s) released by blood vessels.
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心肌细胞中的收缩蛋白受血管释放的因子调节。
DOI：
10.1161/01.res.70.4.787
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发表时间：
1992
影响因子：
20.1
通讯作者：
Winegrad,S
中科院分区：
文献类型：
--
作者：
McClellan,G;Weisberg,A;Kato,NS;Ramaciotti,C;Sharkey,A;Winegrad,S
本文研究了冠状动脉灌注对大鼠心肌细胞肌球蛋白ATP酶活性的调节作用。定量组织化学被用来确定酶的活性在细胞中的组织，已经通过冠状动脉系统灌注或灌注在组织的表面。在来自三种不同制备物的冷冻切片中测量酶活性：1）从动物中取出后立即冷冻的心脏; 2）通过冠状循环灌注后冷冻的分离的心脏;和3）在解剖后灌注然后冷冻的分离的乳头肌或小梁。在解剖后的不同时间在分离的组织中测量ATP酶活性。在解剖后立即冷冻的心室细胞和通过冠状动脉系统灌注的心室细胞中，钙激活和肌动蛋白激活的肌球蛋白ATP酶活性是均匀的。在灌流的组织中，虽然钙激活的肌球蛋白ATP酶活性是均匀的，但肌动蛋白激活的ATP酶活性在解剖后约90分钟内是不均匀的，这段时间是收缩稳定所需的。不均匀性的模式是复杂的。在所有的束中，在最表面的细胞中发现最低的酶活性。在非常薄的束中，中心的细胞具有最高的活性。在中等和较厚的束，有三个同心带的肌动蛋白激活的ATP酶活性，最低的活性，具有高活性的中间区，和具有较低的活性的中心区的表面区。在每个区域内，即使血管没有被灌注，血管旁边的心肌细胞的活性通常最大。肌球蛋白ATP酶活性的横向分布可以通过血管中的细胞（可能是内皮细胞）释放上调肌球蛋白ATP酶活性的物质的机制来解释，释放速率与局部氧张力有关。也可以产生下调物质。收缩的稳定期与肌动球蛋白ATP酶活性模式不均匀的时间一致。这些数据表明，收缩蛋白质的调节由血管产生的物质的比例，当地的PO 2，并可能在血管内皮上的剪切力。
The importance of perfusion of the coronary vasculature in the regulation of ATPase activity of myosin in rat myocardial cells has been studied. Quantitative histochemistry was used to determine the activity of the enzyme among cells in tissues that had been either perfused through the coronary system or superfused over the surface of the tissue. Enzymatic activity was measured in cryostatic sections from three different preparations: 1) hearts frozen immediately after removal from the animal; 2) isolated hearts frozen after they had been perfused through the coronary circulation; and 3) isolated papillary muscles or trabeculae that had been superfused after dissection and then frozen. ATPase activity was measured in the isolated tissues at different times after dissection. Both calcium- and actin-activated myosin ATPase activities were uniform among cells in both the ventricles of the hearts frozen immediately after dissection and those that had been perfused through the coronary system. In the superfused tissues, although calcium-activated myosin ATPase activity was uniform, actin-activated ATPase activity was not uniform for about 90 minutes after the dissection, the period required for stabilization of the contraction. The pattern of nonuniformity was complex. In all bundles the lowest enzymatic activity was found in the most superficial cells. In very thin bundles, the cells in the center had the highest activity. In the medium and thicker bundles, there were three concentric zones of actin-activated ATPase activity, the superficial zone with the lowest activity, an intermediate zone with high activity, and a central zone with lower activity. Within each zone, the activity was often greatest in myocardial cells immediately next to blood vessels even though the blood vessels had not been perfused. The transverse distribution of ATPase activity of myosin could be explained by a mechanism in which cells in blood vessels (presumably endothelium) release a substance that upregulates myosin ATPase activity, with the rate of release being related to the local oxygen tension. A downregulating substance may also be produced. The period of stabilization of the contraction coincides with the time during which the pattern of actomyosin ATPase activity is nonuniform. These data suggest that the contractile proteins are regulated by a substance produced by blood vessels in proportion to the local PO2, and possibly in relation to shear force on the vascular endothelium.