Effect of hypoxia and intravenous anesthetics on calcium sensitization of contraction in cerebral vascular smooth muscle

缺氧和静脉麻醉药对脑血管平滑肌收缩钙敏化的影响

• 批准号: 12671456
• 负责人: FUJIHARA Hideyoshi
• 金额: $ 2.37万
• 依托单位: Niigata University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12671456/
• 关键词: cerebral artery; small GTP binding protein; Y-27632

To study the effect of intravenous anesthetics on the calcium sensitization of contraction in porcine cerebral arterial smooth muscle,1) isometric force was measured in permeabilized smooth muscle at constant (clamped) intracellular calcium concentration. Smooth muscles were stimulated with PGF2α, endothelin, U46619, or GTPγS.2) To see the participation of one of small GTP binding protein, RhoA, and its downstream effecor, Rho-kinase (Rock II) in the calcium sensitization, the inhibitor for RhoA, exoenzyme C3, for Rho-kinase, Y-27632 were used. Intravenous anesthetics, which have a vasodilating effect, were applied to see the potential therapeutic effect on the cerebral vasospasm.We found that1) RhoA/Rho-kinase may be responsible for the mechanism of calcium sensitization of contraction induced by PGF2α, endothelin, U-46619, or GTPγS in the cerebral artery.2) Intravenous anesthetics, ketamine, thiamylal, propofol had little effect on the calcium sensitization of contraction induced by PGF2α, endothelin, U-46619, or GTPγS in the cerebral artery.3) Ketamine at higher concentration, potentiated the myosin phosphatase activity when relaxation was induced at pCa 4.5, with myosin kinase inhibitor, ML-9.4) Western blotting analysis showed the presence of RhoA, Rho-kinase (Rock II), RhoGDI in the cerebral artery.The mechanism of potentiation by ketamine of the myosin phosphatase activity remained to be clarified. Another mechanism of calcium sensitization of contraction, by PKC, with specification of isoenzyme, awaits for further investigation.In summary, it is suggested that the suppression of the calcium sensitization of contraction through RhoA/Rho-kinase in cerebral artery may be useful as one of potential pharmacological intervention for the vasospasm after subarachnoid hemorrhage in human.

为了研究静脉麻醉药对猪脑动脉平滑肌收缩的钙敏感性的影响，1）在恒定的（夹紧的）细胞内钙浓度下，测量透化平滑肌的等长力。用PGF_（2 α）、ET、U_（46619）或GTPγ S刺激平滑肌。2）为了观察小GTP结合蛋白RhoA及其下游效应物Rho激酶（Rock Ⅱ）在钙增敏中的作用，使用RhoA的抑制剂外切酶C_3和Rho激酶的抑制剂Y-27632。结果发现：（1）RhoA/Rho激酶可能参与了PGF_（2 α）、ET、U-46619或GTPγS引起的脑动脉收缩的钙敏感化机制;（2）氯胺酮、甲硫氨酸、苯丙氨酸、苯异丙酚对PGF_（2 α）、ET、U-46619、GTPγS引起的脑动脉收缩的钙敏感性无明显影响。3）高浓度氯胺酮在pCa 4.5诱导舒张时，与肌球蛋白激酶抑制剂一起增强肌球蛋白磷酸酶活性，ML-9.4）Westernblotting分析显示脑动脉中存在RhoA、Rho激酶（Rock II）、RhoGDI。氯胺酮增强肌球蛋白磷酸酶活性的机制尚待阐明。PKC介导的另一种钙敏感性收缩机制及其同工酶的特异性有待进一步研究，提示RhoA/Rho激酶抑制脑动脉钙敏感性收缩可能是治疗蛛网膜下腔出血后血管痉挛的潜在药物之一。

项目成果

Zhan RZ.: "Intravenous anesthetics differentially reduce neurotransmission damage caused by oxygen-glucose deprivation in rat hippocampal slices in correlation with NMDA receptor inhibition"Crit. Care Med.. 29-4. 808-813 (2001)

Zhan RZ.：“静脉麻醉药可不同地减少大鼠海马切片中氧-葡萄糖剥夺引起的神经传递损伤，与 NMDA 受体抑制相关”Crit。

Wu C.: "A forebrain ischemic preconditioning model established in C57Black/Crj6 mice"J. Neuroscience Methods.. 107・1-2. 101-106 (2001)

Wu C.：“在C57Black/Crj6小鼠中建立前脑缺血预处理模型”J. NeuroscienceMethods.. 107・1-106（2001）。

Zhan RZ.: "Both Caspase-dependent and -independent pathways may be involved in hippocampal neuronal death due to loss of cytochromec from mitochondria in a forebrain ischernia"J. Cerebral Blood Flow and Metabolism.. 21・5. 529-540 (2001)

Zhan RZ.：“Caspase 依赖性和非依赖性途径都可能与前脑缺血中线粒体细胞色素丢失导致的海马神经元死亡有关”J. Cerebral Blood Flow and Metabolism.. 21・5. (2001) ）

HIdeyoshi Fujihara: "The effect of ketamine on the relaxation under MLCK inhibition in porcine cerebral artery"Cerebral Blood Flow and Metabolism. 13-4. 312-313 (2001)

Hideyoshi Fujihara：“氯胺酮对猪大脑动脉 MLCK 抑制下松弛的影响”脑血流和代谢。

冨士原 秀善: "摘出ブタ脳血管収縮におよぼす静脈麻酔薬の影響"脳循環代謝. 14(印刷中). (2002)

Hideyoshi Fujihara：“静脉麻醉药对离体猪脑血管收缩的影响”《脑循环与代谢》14（出版中）。