Ganguly P K
Department of Anatomy, St. Boniface General Hospital Research Centre, Winnipeg, Manitoba, Canada.
Angiology. 1991 Feb;42(2):133-9. doi: 10.1177/000331979104200207.
In order to support the hypothesis that oxygen free radicals derived from persistent sympathetic drive play an important role in the modulation of receptor-mediated effect in cardiac hypertrophy, rat hearts subjected to aortic banding-induced pressure overload were assessed on postoperative days 3, 14, and 28. Sham-operated rats without aortic banding were used as a control group. Cardiac alpha-adrenoceptors were increased at day 3 whereas beta-adrenoceptors were increased at postoperative days 14 and 28; these results were associated with increased amount of circulating norepinephrine and adrenolutin, one of the oxidation products of catecholamines. The hearts of these animals were also perfused by Langendorff technique in the presence and absence of adrenergic agonists. Banded animals had a diminished inotropic response to alpha agonists in addition to their reduced inotropic responsiveness to beta-adrenergic stimuli. These changes were however, reversible in animals pretreated with alpha-tocopherol, a powerful antioxidant. Furthermore, the circulating level of adrenolutin was normalized by such treatment. These results indicate that an oxidation product of catecholamines may be responsible for impaired inotropic responses to adrenergic stimulation following aortic constriction.
为了支持以下假说，即持续交感神经驱动产生的氧自由基在心脏肥大中受体介导效应的调节中起重要作用，对术后第3天、14天和28天的主动脉缩窄诱导压力超负荷的大鼠心脏进行了评估。未进行主动脉缩窄的假手术大鼠用作对照组。心脏α-肾上腺素能受体在术后第3天增加，而β-肾上腺素能受体在术后第14天和28天增加；这些结果与循环中去甲肾上腺素和肾上腺素红（儿茶酚胺的氧化产物之一）水平升高有关。还通过Langendorff技术在有和没有肾上腺素能激动剂的情况下对这些动物的心脏进行灌注。除了对β-肾上腺素能刺激的变力反应降低外，主动脉缩窄动物对α激动剂的变力反应也减弱。然而，在用强力抗氧化剂α-生育酚预处理的动物中，这些变化是可逆的。此外，通过这种治疗，肾上腺素红的循环水平恢复正常。这些结果表明，儿茶酚胺的一种氧化产物可能是主动脉缩窄后对肾上腺素能刺激的变力反应受损的原因。
