Yang Z W, Zheng T, Wang J, Zhang A, Altura B T, Altura B M
Department of Physiology, State University of New York, Health Science Center at Brooklyn, 11203, USA.
Naunyn Schmiedebergs Arch Pharmacol. 1999 Dec;360(6):646-53. doi: 10.1007/s002109900128.
The effects of hydrogen peroxide (H2O2) on isolated canine basilar arteries, and single smooth muscle cells isolated from these arteries, were investigated in the present study. Exposure of isolated endothelium-intact and denuded arterial rings to H2O2, at concentrations of 2.2x10(-5) M to 4.4x10(-3) M, produced concentration-dependent contractile responses. Removal of the endothelium attenuated, but did not eliminate the contractions. H2O2-induced contractions were inhibited, to different degrees, by preincubation of the vessels with low concentrations of staurosporine or bisindolylmaleimide I HCl [antagonists of protein kinase C (PKC)], Gö6976 (a PKCalpha and PKCbeta1 selective antagonist), genistein (an antagonist of protein tyrosine kinase), PD-98059 (an antagonist of mitogen-activated protein kinase), wortmannin [an antagonist of phosphatidylinositol 3 (PI3)-kinases], and LY-294002 (an antagonist of PI3-kinases). These agents were also found to relax arteries precontracted by H2O2. Removal of extracellular Ca2+ or pretreatment of the vessels with 5.0 microM verapamil markedly attenuated the contractions. Complete inhibition of the contractile response was obtained after buffering intracellular Ca2+ with BAPTA-AM. A variety of specific pharmacological antagonists of several known vasoconstrictors neither inhibited nor attenuated the H2O2-induced contractions. Exposure of smooth muscle cells to H2O2 (4.4x10(-6) M to 4.4x10(-4) M) significantly raised intracellular Ca2+ ([Ca2+]i) within 20 s. This was abolished in the absence of extracellular Ca2+ or after application of 5.0 microM verapamil. Pretreatment of the cells with low concentrations of staurosporine, bisindolylmaleimide I, Gö6976, genistein, PD-98059, wortmannin, and LY-294002 markedly suppressed the H2O2-mediated [Ca2+]i elevation. The present findings suggest that hydrogen peroxide, in vitro, produces endothelium-dependent and independent contractions of canine basilar arteries, which are clearly Ca2+-dependent and are not associated with release of endogenous vasoconstrictors. Several intracellular signal transduction systems, such as PKC (both Ca2+-dependent and Ca2+-independent), protein tyrosine phosphorylation, IP3, mitogen-activated protein kinase and PI3 kinase appear to play a role in the H2O2-induced contractions in cerebral arterial muscle.
本研究调查了过氧化氢（H₂O₂）对离体犬基底动脉以及从这些动脉分离出的单个平滑肌细胞的影响。将完整内皮和去内皮的离体动脉环暴露于浓度为2.2×10⁻⁵ M至4.4×10⁻³ M的H₂O₂中，可产生浓度依赖性收缩反应。去除内皮可减弱但不能消除收缩。低浓度的星形孢菌素或双吲哚马来酰亚胺I HCl[蛋白激酶C（PKC）拮抗剂]、Gö6976（一种PKCalpha和PKCbeta1选择性拮抗剂）、染料木黄酮（一种蛋白酪氨酸激酶拮抗剂）、PD - 98059（一种丝裂原活化蛋白激酶拮抗剂）、渥曼青霉素[磷脂酰肌醇3（PI3）激酶拮抗剂]和LY - 294002（一种PI3激酶拮抗剂）预先孵育血管，可不同程度地抑制H₂O₂诱导的收缩。还发现这些药物可使由H₂O₂预收缩的动脉舒张。去除细胞外Ca²⁺或用5.0微摩尔维拉帕米预处理血管可显著减弱收缩。用BAPTA - AM缓冲细胞内Ca²⁺后可完全抑制收缩反应。几种已知血管收缩剂的多种特异性药理拮抗剂既不抑制也不减弱H₂O₂诱导的收缩。将平滑肌细胞暴露于H₂O₂（4.4×10⁻⁶ M至4.4×10⁻⁴ M）中，20秒内细胞内Ca²⁺（[Ca²⁺]i）显著升高。在无细胞外Ca²⁺时或应用5.0微摩尔维拉帕米后，这种升高被消除。用低浓度的星形孢菌素、双吲哚马来酰亚胺I、Gö6976、染料木黄酮、PD - 98059、渥曼青霉素和LY - 294002预处理细胞可显著抑制H₂O₂介导的[Ca²⁺]i升高。目前的研究结果表明，在体外，过氧化氢可引起犬基底动脉的内皮依赖性和非内皮依赖性收缩，这些收缩明显依赖Ca²⁺，且与内源性血管收缩剂的释放无关。几种细胞内信号转导系统，如PKC（钙依赖性和非钙依赖性）、蛋白酪氨酸磷酸化、IP3、丝裂原活化蛋白激酶和PI3激酶似乎在H₂O₂诱导的脑动脉平滑肌收缩中起作用。
