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目的探讨急性缺血性脑血管病血小板肌球蛋白轻链激酶（ＭＬＣＫ）和Ｃａ２＋、Ｍｇ２＋－ＡＴＰ酶活性的变化及与血小板胞浆游离钙浓度［Ｃａ２＋］ｉ的关系。方法用３２Ｐ同位素掺入法和比色法分别测定５８例脑缺血病人，及３５名健康对照者血小板ＭＬＣＫ和Ｃａ２＋、Ｍｇ２＋－ＡＴＰ酶活性。用荧光钙指示剂Ｆｕｒａ－２负载血小板扫描的方法，测定脑缺血病人血小板［Ｃａ２＋］ｉ浓度。结果ＴＩＡ组和脑梗死组ＭＬＣＫ活性与对照组相比均有明显增加（Ｐ＜０．０１），而Ｃａ２＋Ｍｇ２＋－ＡＴＰ酶活性均低于对照组（Ｐ＜０．０５，Ｐ＜０．０１）。ＴＩＡ组和脑梗死组血小板静息［Ｃａ２＋］ｉ；均高于对照组；血小板静息［Ｃａ２＋］ｉ与血小板ＭＬＣＫ活性呈显著正相关（Ｐ＜０．０１），而与血小板Ｃａ２＋、Ｍｇ２＋－ＡＴＰ酶活性呈负相关（Ｐ＜０．０５）。结论血小板ＭＬＣＫ和Ｃａ２＋、Ｍｇ２＋－ＡＴＰ酶活性与急性缺血性脑血管病的发生有密切关系，ＭＬＣＫ活性的变化可能是脑缺血病人血小板活化的分子基础。
Objective To investigate the changes of platelet myosin light chain kinase (MLCK) and Ca2 +, Mg2 + -ATPase activity in acute ischemic cerebrovascular disease and its relationship with [Ca2 +] i of platelet cytoplasm. Methods The platelet MLCK and Ca2 +, Mg2 + -ATPase activities of 58 cerebral ischemic patients and 35 healthy controls were determined by 32P isotope incorporation and colorimetry, respectively. The concentration of platelet [Ca2 +] i in patients with cerebral ischemia was measured by fluorescently loaded Fura-2 loaded platelet scanning. Results The activity of MLCK in TIA group and cerebral infarction group were significantly higher than those in control group (P <0.01), while the activity of Ca2 + Mg2 + -ATP was lower than that in control group (P <0.05, P <0.01) . The platelet resting [Ca2 +] i in TIA group and cerebral infarction group were higher than those in control group. The resting platelet Ca2 + i was positively correlated with platelet MLCK activity (P <0.01), but not with platelet Ca2 +, Mg2 + ATPase activity was negatively correlated (P <0.05). Conclusion MLCK and Ca2 +, Mg2 + -ATPase activities of platelets are closely related to the occurrence of acute ischemic cerebrovascular disease. The changes of MLCK activity may be the molecular basis of platelet activation in patients with cerebral ischemia.