Possible role of protein kinase-dependent smooth muscle contractile mechanism in the occurrence of delayed spasm after subarachnoid hemorrhage

蛋白激酶依赖性平滑肌收缩机制在蛛网膜下腔出血后迟发性痉挛发生中的可能作用

基本信息

批准号：
10671316
负责人：
MATSUI Toru
金额：
$ 2.24万
依托单位：
SAITAMA MEDICAL SCHOOL
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

We have already reported the following experimental evidence suggesting that PKC (protein kinase C) activation participates in the occurrence of chronic vasospasm following subarachnoid hemorrhage. 1] The canine basilar artery (BA) possesses a PKC system which fully functions even in the Ca^<2+>-free medium, and that the narrowing or the augmented tonus of the BA exposed to 'two-hemorrhage' can be reversed by application of PKC inhibitors such as H-7 and staurosporine either in vivo or in vitro condition. 2] The content of 1,2-diacylglycerol, an intrinsic PKC activator, is significantly increased through the stimulated turnover of phosphatidylcholine and phosphatidylethanolamine in the spastic BA in comparison with that in the nonspastic BA.3] In spastic arteries at Days 4 and 7, the cytosolic PKC activity showed a decrease of 40-45% with no significant changes in membrane PKC activity as compared with nonspastic control arteries. The extent of 20 kDa myosin light chain phosphorylation … More was unchanged between the spastic and nonspastic BA.On Day 14, the cytosolic PKC activity of arteries returned toward the normal control level with the remission of vasospasm. Western blot analysis of the PKC isoforms revealed that the amounts of PKCα and PKCε but not PKCζ were down-regulated in spastic arteries, suggesting the activation of PKCα and PKCε in the course of chronic vasospasm. 4] The augmentation of active smooth muscle contraction, possibly induced by PKC activation, plays a role in the occurence of chronic vasospasm which is more important than the altered passive physical properties of the arterial wall (decreased dispensability of arterial wall). 5] In addition, it is revealed that oxidized diacylglycerol induces sustained contraction of normal and skinned BA.Under the pCa=5.5, an incubation of skinned basilar artery with palmitoyl-arachidonyl diacylglycerol-hydroperoxide (5xl0^<-5>M) shows a remarkable down-regulation of PKC a and e. As it is known that the down-regulation of the protein is the direct evidence to show its preceding activation, the oxidized-diacylglycerol induced contraction is thought to be mediated by an activation of PKC a orε. 6] Finally, PAG=OH and PLG-OH as an oxidized DAG were found in the brain tissue subjected to experimental subarachnoid hemorrhage. The above line of investigations render it likely that PKC activation, especially type e which is though to play a central role in the calciun-independent mechanism of smooth muscle contraction, participates in the occurrence of chronic vasospasm following subarachnoid hemorrhage Less

我们已经报道了以下实验证据，表明PKC（蛋白激酶C）激活参与蛛网膜下腔出血后慢性血管痉挛的发生。 1]犬基底动脉（BA）具有一个PKC系统，该系统即使在CA^<2+> - 游离培养基中都能充分发挥作用，并且可以通过应用PKC抑制剂（例如H-7和Staurosporine coil Invivo或Vitro in Vivo或Vitro in vivo）来逆转暴露于“两次渗透率”的BA的狭窄或增强量。 2] 1,2-二酰基甘油是一种固有的PKC激活剂，通过在痉挛性BA中刺激的磷脂酰胆碱和磷脂酰硫代苯胺的刺激量显着增加，与非propatical Ba.3]相比，在第4和7天，在4和第7天，在没有弹性动脉中的磷酸BA中，磷酸ba的含量显着增加。与非刺激对照动脉相比，PKC活性。 20 kDa肌球蛋白轻链磷酸化的范围……在第14天的痉挛和非痉挛性BA.之间，动脉的胞质PKC活性恢复了正常的控制水平，随着血管痉挛的缓解。 PKC同工型的蛋白质印迹分析表明，在痉挛性动脉中，PKCα和PKCε而不是PKCζ的量下调，这表明在慢性血管痉挛过程中，PKCα和PKCε的激活。 4]在PKC激活中可能引起的活跃平滑肌收缩的增强在慢性血管痉挛的发生中起作用，这比动脉壁的被动物理特性更为重要（动脉壁的可算可降低）。 5]此外，还发现氧化的二酰基甘油会诱导正常和皮肤的BA持续收缩。在PCA = 5.5，A 6]最后，PAG = OH，PLG-OH作为氧化DAG，在经受实验性蛛网膜下腔出血的脑组织中发现了氧化DAG。上述调查线使PKC激活，尤其是E型激活，尽管在平滑肌合同的无关机制中起着核心作用