State Key Laboratory of Trauma, Burns and Combined Injury, The 2nd Department of Research Institute of Surgery, Daping Hospital, The Third Military Medical University, Chongqing, PR China.
Eur J Pharmacol. 2010 Feb 25;628(1-3):148-54. doi: 10.1016/j.ejphar.2009.11.040. Epub 2009 Nov 26.
The present study investigated the mediated effect of protein kinase C (PKC) in arginine vasopressin (AVP)-induced restoration of vascular responsiveness and calcium sensitization following hemorrhagic shock. Using both isolated superior mesenteric artery from hemorrhagic shock rats and hypoxia-treated vascular smooth muscle cell (VSMC), we investigated the roles of PKC-alpha, delta and epsilon isoforms in AVP-induced restoration of vascular reactivity and calcium sensitivity. Meanwhile, effects of their specific inhibitors on the activity of myosin light chain phosphatase (MLCP), myosin light chain kinase (MLCK), and the phosphorylation of myosin light chain (MLC(20)) in VSMC were observed. The results indicated that AVP improved the reactivity of superior mesenteric artery and VSMC to norepinephrine and calcium following hemorrhagic shock and hypoxia. PKC-alpha inhibitor and PKC-epsilon inhibitory peptide antagonized these effects of AVP, while PKC-delta inhibitor only partially antagonized these effects of AVP. AVP up-regulated the expression of PKC-alpha and epsilon in the particulate fractions of hypoxia-treated VSMC with the decrease of the activity of MLCP and the increase of the phosphorylation of MLC(20). These effects of AVP were inhibited by PKC-alpha inhibitor and PKC-epsilon inhibitory peptide, but not by the PKC-delta inhibitor. The results suggested that PKC plays an important role in AVP-induced restoration of vascular reactivity and calcium sensitivity following hemorrhagic shock. PKC-alpha and epsilon may be the main isoforms involved in this process and play effect via MLC(20) phosphorylation dependent mechanism, while PKC-delta may be partially involved in AVP action by other mechanisms.
本研究探讨了蛋白激酶 C（PKC）在血管加压素（AVP）诱导的出血性休克后血管反应性和钙敏恢复中的介导作用。通过使用来自出血性休克大鼠的分离的肠系膜上动脉和缺氧处理的血管平滑肌细胞（VSMC），我们研究了 PKC-α、δ和ε同工型在 AVP 诱导的血管反应性和钙敏感性恢复中的作用。同时，观察了其特异性抑制剂对 VSMC 中肌球蛋白轻链磷酸酶（MLCP）、肌球蛋白轻链激酶（MLCK）活性和肌球蛋白轻链（MLC（20））磷酸化的影响。结果表明，AVP 改善了出血性休克和缺氧后肠系膜上动脉和 VSMC 对去甲肾上腺素和钙的反应性。PKC-α抑制剂和 PKC-ε抑制肽拮抗 AVP 的这些作用，而 PKC-δ抑制剂仅部分拮抗 AVP 的这些作用。AVP 上调了缺氧处理的 VSMC 颗粒部分中 PKC-α和 epsilon 的表达，同时降低了 MLCP 的活性，增加了 MLC（20）的磷酸化。这些 AVP 的作用被 PKC-α抑制剂和 PKC-ε抑制肽抑制，但不受 PKC-δ抑制剂的影响。结果表明，PKC 在 AVP 诱导的出血性休克后血管反应性和钙敏感性恢复中起重要作用。PKC-α和 epsilon 可能是参与该过程的主要同工型，通过 MLC（20）磷酸化依赖机制发挥作用，而 PKC-δ可能通过其他机制部分参与 AVP 作用。
