Ventura C, Guarnieri C, Bastagli L, Caldarera C M
Department of Biochemistry, University of Bologna, Italy.
Basic Res Cardiol. 1988 Jul-Aug;83(4):376-83. doi: 10.1007/BF02005823.
The present study demonstrates that the bovine cardiac sarcolemma possesses an NAD(P)H dehydrogenase activity which is able to oxidize both NADH and NAD(P)H in the presence of vanadate as an electron acceptor. The NADH dehydrogenase activity was significantly higher than the NAD(P)H dehydrogenase activity and both of them were almost completely inhibited by superoxide dismutase and atebrin and markedly reduced by the addition of the protonophore 2,4-dinitrophenol. The incubation of the sarcolemma in the presence of 10(-10), 10(-9), 10(-8) M methionine-enkephalin, a prevalent delta-opioid receptor agonist, or dynorphin A (1-17), a prevalent kappa-receptor agonist, produced a dose-dependent increase in the NAD(P)H dehydrogenase activity, with 10(-10) and 10(-9) M dynorphin A (1-17) more effective than the corresponding doses of methionine-enkephalin. The preincubation of the sarcolemma in the presence of superoxide-dismutase, atebrin or 2,4-dinitrophenol strongly inhibited the opioid-stimulated dehydrogenase activity. The stimulatory action elicited by 10(-8) M methionine-enkephalin or dynorphin A (1-17) was completely antagonized by 10(-8) M naloxone or Mr 1452, respectively, whilst 10(-8) M naloxone exerted only a partially antagonistic action against the effect produced by 10(-8) M dynorphin A (1-17), significantly more accentuated than the action of 10(-8) M Mr 1452 versus the same dose of methionine-enkephalin.
本研究表明，牛心肌肌膜具有NAD(P)H脱氢酶活性，在钒酸盐作为电子受体存在的情况下，该酶能够氧化NADH和NAD(P)H。NADH脱氢酶活性显著高于NAD(P)H脱氢酶活性，二者几乎都被超氧化物歧化酶和阿的平完全抑制，并且通过添加质子载体2,4-二硝基苯酚可使其显著降低。在存在10(-10)、10(-9)、10(-8) M甲硫氨酸脑啡肽（一种常见的δ阿片受体激动剂）或强啡肽A(1-17)（一种常见的κ受体激动剂）的情况下孵育肌膜，会使NAD(P)H脱氢酶活性呈剂量依赖性增加，10(-10)和10(-9) M强啡肽A(1-17)比相应剂量的甲硫氨酸脑啡肽更有效。在超氧化物歧化酶、阿的平或2,4-二硝基苯酚存在的情况下预孵育肌膜，会强烈抑制阿片类药物刺激的脱氢酶活性。10(-8) M甲硫氨酸脑啡肽或强啡肽A(1-17)引发的刺激作用分别被10(-8) M纳洛酮或Mr 1452完全拮抗，而10(-8) M纳洛酮仅对10(-8) M强啡肽A(1-17)产生的效应发挥部分拮抗作用，比10(-8) M Mr 1452对相同剂量甲硫氨酸脑啡肽的作用更明显。
