Kasten T P, Settle S L, Misko T P, Currie M G, Nickols G A
Department of Pharmacological and Physiological Sciences, Saint Louis University School of Medicine, MO.
Eur J Pharmacol. 1994 Feb 21;253(1-2):35-43. doi: 10.1016/0014-2999(94)90754-4.
The half-life of nitric oxide (NO) and the relaxation of aortic-rings are enhanced by superoxide dismutase. Manganese and manganese-containing preparations have been reported to mimic superoxide dismutase activity. In the current study, manganese was tested for its ability to potentiate the activity of NO both in vitro and in vivo. Manganese relaxation of aortic segments was endothelium dependent as well as concentration dependent. Cyclic GMP concentrations in the segments were increased 2- and 4-fold with 5 and 300 microM manganese, respectively. N-Monomethyl-L-arginine pretreatment of aortic rings abolished the relaxation and cyclic GMP accumulation mediated by manganese. Infusion of manganese into conscious, restrained rats resulted in a decrease of blood pressure which was abolished by N-nitro-L-arginine pretreatment. Therefore, manganese may prolong the half-life of NO by a mechanism that mimics the action of superoxide dismutase resulting in potentiation of NO actions in vascular tissue.
超氧化物歧化酶可延长一氧化氮（NO）的半衰期并增强主动脉环的舒张作用。据报道，锰及含锰制剂可模拟超氧化物歧化酶的活性。在本研究中，对锰在体外和体内增强NO活性的能力进行了测试。锰对主动脉段的舒张作用依赖于内皮且具有浓度依赖性。分别用5微摩尔和300微摩尔锰处理后，主动脉段中环磷酸鸟苷（cGMP）的浓度分别增加了2倍和4倍。用N-单甲基-L-精氨酸预处理主动脉环可消除锰介导的舒张作用和cGMP积累。向清醒、受限的大鼠体内注入锰会导致血压下降，而N-硝基-L-精氨酸预处理可消除这种作用。因此，锰可能通过模拟超氧化物歧化酶的作用机制来延长NO的半衰期，从而增强NO在血管组织中的作用。
