Pathophysiological and molecular pharmacological studies on the role of reactive oxygen species in disorder of circulatory function.

通过测量有内皮和无内皮兔隐动脉的光致发光信号来研究超氧化物的产生水平。蛋白激酶C(PKC)的激活剂佛波醇12，13-二丁酸酯(PDBu)可增强有内皮和无内皮制剂的化学发光信号。在此条件下，超氧化物歧化酶(SOD)大大减弱了化学发光信号。GF109203(PKC的选择性抑制剂)和二苯碘氯(NAD(P)H氧化酶的抑制剂)均抑制化学发光信号。这些结果表明，PKC激活NAD(P)H可增加血管平滑肌细胞(可能也包括内皮细胞)中超氧化物的生成。次黄嘌呤+黄嘌呤氧化酶产生的超氧化物可抑制去甲肾上腺素(NAD)引起的兔肠系膜动脉内皮剥脱条的收缩。这一超氧化物诱导的反应被超氧化物歧化酶增强，但被过氧化氢酶或AS…抑制更多的坏血酸。这些结果表明，在生理条件下，超氧化物歧化酶能将超氧化物歧化为H_2O_2，从而抑制NAD引起的血管平滑肌收缩。H_2O_2超极化的血管肌细胞膜可被环氧合酶抑制剂双氯芬酸钠和K_1通道抑制剂格列本脲所抑制。这些结果表明，H_2O_2通过激活K_lt；ATP和Gt；通道而增加前列腺素的合成，从而使平滑肌细胞膜超极化。提示H_2O_2诱导的膜超极化在H_2O_2引起的兔肠系膜动脉NAD收缩的松弛中起重要作用。在β-七叶皂苷钠所致的兔肠系膜动脉平滑肌中，NAD和GTP联合增强0.3μM Ca~(2+)和Gt~(2+)引起的收缩。在NAD+GTP存在和不存在的情况下，H_2O_2对Ca~(2+)收缩无影响，提示H_2O_2对兔肠系膜动脉血管平滑肌收缩蛋白的Ca~(2+)敏感性无直接作用。较少

The level of superoxide production was investigated by measuring lucigenin chemiluminescence signals in rabbit saphenous arteries with and without endothelium. Phorbol 12, 13-dibutirate (PDBu), an activator of protein kinase C (PKC), increased the chemiluminescence signals in preparations with and without endothelium. Under the conditions, superoxide dismutase(SOD) greatly attenuated the chemiluminescence signals. Each GF109203 (a selective inhibitor of PKC) and diphenylene iodochloride [an inhibitor of NAD (P) H oxidase] inhibited the chemiluminescence signals. These results suggest that an activation of NAD (P) H by PKC enhances generation of superoxide in vascular smooth muscle cells (and possibly in endothelial cells).Superoxide generated by hypoxanthine + xanthine oxidase inhibited the contraction induced by noradrenaline (NAd) in endothelium-denuded strips of rabbit mesenteric arteries. This superoxide-induced response was enhanced by SOD, but this was inhibited by catalase or as … More corbic acid. These results suggest that under physiological conditions, SOD breaks down superoxide to H_2O_2 that inhibits the NAd-induced contraction in vascular smooth muscles.H_2O_2 hyperpolarized smooth muscle cell membrane, which was inhibited by diclofenac sodium (an inhibitor of cyclooxygenase), and by glibenclamide (an inhibitor of K_<ATP> channels). These results suggest that H_2O_2 increases the synthesis of prostaglandins that hyperpolarizes the smooth muscle cell membrane through an activation of K_<ATP> channels. It is also suggested that the H_2O_2-induced membrane hyperpolarization plays an important role on the H_2O_2-induced relaxation on NAd-contraction in rabbit mesenteric artery.In β-escin-skinned smooth muscles of rabbit mesenteric arteries, NAd plus GTP enhanced the contraction induced by 0.3 μM Ca^<2+>. H_2O_2 had no effect on the Ca^<2+>-contraction in the presence and absence of NAd plus GTP, suggesting that H_2O_2 has no direct action on the Ca^<2+>-sensitivity of contractile proteins in vascular smooth muscles of rabbit mesenteric artery. Less