蛋白激酶Cs在咪达唑仑舒张自发性高血压大鼠主动脉平滑肌中的作用和机制  

Role and mechanism of PKCs in midazolam-induced relaxation of aortic smooth muscle in spontaneously hypertensive rats

作　　者：单宇[1] 汪文英[1] 张晖[1] 汪燕[1] SHAN Yu;WANG Wen-ying;ZHANG Hui;WANG Yan(Dept of Anesthesiology,the Sixth People′s Hospital,Shanghai Jiaotong University,Shanghai 200233,China)

机构地区：[1]上海交通大学附属第六人民医院麻醉科,上海200233

出　　处：《中国药理学通报》2023年第6期1054-1060,共7页Chinese Pharmacological Bulletin

基　　金：国家自然科学基金资助项目(No 82000396)。

摘　　要：目的探讨蛋白激酶Cs(protein kinase C,PKCs)在咪达唑仑舒张自发性高血压大鼠(spontaneously hypertensive rat,SHR)主动脉平滑肌中的作用和机制。方法利用离体血管环张力测定系统,观察咪达唑仑对SHR和Wistar-Kyoto(WKY)大鼠主动脉平滑肌的舒张作用。分别用PKCs广谱抑制剂GF109203X(GF)、PKCβ2特异性抑制剂LY333531(LY)和PKCθ假底物(PKCθpseudo-substrate inhibitor,PPS)预孵育后,观察咪达唑仑舒张幅度的变化。利用Western blot检测咪达唑仑对SHR主动脉平滑肌中PKCβ2磷酸化水平的影响,以及咪达唑仑、LY、GF和PPS对SHR主动脉平滑肌中钙敏感通路蛋白磷酸化水平的影响。结果咪达唑仑浓度依赖性地舒张SHR和WKY的主动脉平滑肌。GF明显抑制了咪达唑仑对SHR和WKY主动脉平滑肌的舒张幅度。LY和PPS对咪达唑仑舒张WKY主动脉平滑肌的幅度没有明显影响,而LY明显抑制了咪达唑仑舒张SHR主动脉平滑肌的幅度。咪达唑仑明显抑制了SHR主动脉平滑肌中NE诱导的PKCβ2磷酸化水平的升高。咪达唑仑、LY和GF均明显抑制了SHR主动脉平滑肌中NE诱导的钙敏感通路蛋白磷酸化水平的升高。结论咪达唑仑通过抑制PKCβ2介导的钙敏感通路,引起SHR主动脉平滑肌的过度舒张反应。Aim To investigate the effect of protein kinase C(PKCs)on midazolam-induced relaxation of aortic smooth muscle in spontaneously hypertensive rats(SHR)and the underlying mechanism.Methods Using the isolated vessel tension measurement system,the relaxant effect of midazolam on aortic smooth muscle of SHR and Wistar-Kyoto(WKY)rats was observed.After preincubation with GF109203X(GF,a broad-spectrum inhibitor of PKCs),LY333531(LY,PKCβ2 specific inhibitor)and PKCθpseudo-substrate inhibitor(PPS),the changes of midazolam-induced relaxation amplitude were observed.Western blot was used to detect the effect of midazolam on the phosphorylation level of PKCβ2 in SHR aortic smooth muscle.The effect of midazolam,LY,GF and PPS on the phosphorylation level of the key proteins(CPI-17/MYPT1/MLC)in calcium sensitization pathway in SHR aortic smooth muscle was also examined.Results Midazolam concentration-dependently relaxed aortic smooth muscle in SHR and WKY.GF significantly inhibited midazolam-induced relaxation amplitude of SHR and WKY aortic smooth muscle.LY and PPS had no significant effect on midazolam-induced relaxation amplitude of WKY aortic smooth muscle.In contrast,LY markedly inhibited midazolam-induced relaxation amplitude of SHR aortic smooth muscle.Midazolam significantly inhibited the phosphorylation level of PKCβ2 enhanced by NE in SHR aortic smooth muscle.Midazolam,LY and GF all evidently inhibited the phosphorylation level of the key proteins in calcium sensitization pathway enhanced by NE in SHR aortic smooth muscle.Conclusions Midazolam induces excessive relaxation of SHR aortic smooth muscle by inhibiting calcium sensitization pathway mediated by PKCβ2.

关 键 词：咪达唑仑 自发性高血压大鼠 主动脉平滑肌 PKCβ2 PKCΘ 钙敏感 

分 类 号：R-332[医药卫生] R322.121R322.74R345.57R544.1R971.3R614R971