蛋白激酶在Cx40、Cx43调节缺氧处理大鼠肠系膜上动脉收缩反应性中的作用

Effect of protein kinases on Cx40/43 regulating endothelium-dependent vascular contractile reactivity of superior mesenteric artery treated by hypoxia

目的研究蛋白激酶A(PKA)、蛋白激酶G(PKG)、蛋白激酶C(PKC)在连接蛋白Cx40、Cx43调节缺氧处理大鼠肠系膜上动脉(SMA)内膜依赖的收缩反应性中的作用。方法以SD大鼠SMA为研究对象,用Cx40或Cx43的反义寡脱氧核苷酸(AODN)阻断SMA的Cx40或Cx43表达,观察缺氧处理SMA内膜依赖的收缩反应性的变化,以PKA、PKG、PKC特异性激动剂或拮抗剂改变相关信号通路,观察缺氧SMA在肌球蛋白轻链激酶(MLCK)活性、肌球蛋白轻链磷酸酶(MLCP)活性和内膜依赖的收缩反应性等方面的变化。结果杨梅黄酮(myricetin)、Cx40/43 AODN对常氧和缺氧血管的MLCK活性无明显影响;Cx40 AODN可以降低常氧血管和缺氧血管的MLCP活性,增加内膜依赖的血管收缩反应性;Cx43 AODN可以增加血管的MLCP活性,抑制血管内膜依赖的收缩反应性。8-Br-cAMP(PKA激动剂)、8-Br-cGMP(PKG激动剂)和staurosporine(PKC抑制剂)可以明显增加Cx40/43 AODN处理血管的MLCP活性,降低血管的收缩反应性;H-89(PKA抑制剂)、KT-5823(PKG抑制剂)和PMA(PKC激动剂)可以明显降低Cx40/43 AODN处理血管的MLCP活性,增加Cx40/43 AODN处理血管的收缩反应性。结论 Cx40和Cx43可以通过调节血管MLCP的活性,进而参与了休克血管钙敏感性和血管内膜依赖的收缩反应性的调节,

Objective To investigate the mechanism of Cx40/43 regulating the endothelium-dependent vascular contractile reactivity after hypoxia.Methods With superior mesenteric arteries（SMAs）from rats treated by hypoxia,Cx40/43 antisense oligodeoxyribonucleotide（Cx40/43 AODN）and the specific activators or inhibitors to PKA,PKG and PKC,the changes of myosin light chain kinase′s（MLCK′s）activity,myosin light chain phosphatase′s（MLCP′s）activity and the endothelium-dependent contractile response of hypoxia treated SMA were observed.Results Cx40 AODN decreased the activity of MLCP,but increased the endothelium-dependent contractile response.Cx43 AODN increased the activity of MLCP,but decreased the endothelium-dependent contractile response.8-Br-cAMP（PKA activator）,8-Br-cGMP（PKG activator）and staurosporine（PKC inhibitor）significantly increased the activity of MLCP,but decreased the endothelium-dependent contractile response of SMAs treated by Cx40/43 AODN.H-89（PKA inhibitor）,KT-5823（PKG inhibitor）and PMA（PKC activator）significantly decreased the activity of MLCP,but increased the endothelium-dependent contractile response of SMAs treated by Cx40/43 AODN.Conclusion The possible mechanism that Cx40/43 regulates endothelium-dependent vasoconstrictor reactivity following hemorrhagic shock may be related to the PKA,PKG and PKC signal pathway.