VanKirk Tricia, Powers Evelyn, Dowse Harold B
School of Biology and Ecology, University of Maine, Orono, ME, 04469, USA.
Department of Mathematics and Statistics, University of Maine, Orono, ME, 04469, USA.
J Comp Physiol B. 2017 Jan;187(1):63-78. doi: 10.1007/s00360-016-1019-8. Epub 2016 Jul 22.
Melatonin is a hormone that is critical for normal circadian and seasonal rhythmicity in a wide range of different animals. It is a powerful antioxidant commonly used to prevent reperfusion injury to the heart after infarction. We show here it has other more far-reaching effects on cardiac function. Using the Drosophila model, we show that injection of melatonin increases the regularity of heartbeat significantly and can rescue rhythmicity in flies bearing mutations that adversely affect cardiac function. Notably, melatonin increases cardiac regularity independent of alteration of heart rate. We provide compelling evidence that melatonin's action as an antioxidant is not the mechanism underlying improved cardiac performance. We have strong evidence that melatonin's action on the heart is mediated via a specific G-Protein-coupled receptor encoded by the CG 4313 gene that our results implicate as a candidate melatonin receptor. These results open a line of questioning about fundamental aspects of cardiac pacemaking.
褪黑素是一种对多种不同动物的正常昼夜节律和季节性节律至关重要的激素。它是一种强大的抗氧化剂，常用于预防心肌梗死后心脏的再灌注损伤。我们在此表明，它对心脏功能还有其他更深远的影响。利用果蝇模型，我们发现注射褪黑素能显著提高心跳的规律性，并能挽救携带对心脏功能有不利影响突变的果蝇的节律性。值得注意的是，褪黑素提高心脏规律性与心率改变无关。我们提供了令人信服的证据，证明褪黑素作为抗氧化剂的作用并非改善心脏性能的潜在机制。我们有充分的证据表明，褪黑素对心脏的作用是通过由CG 4313基因编码的特定G蛋白偶联受体介导的，我们的研究结果表明该基因是一种候选褪黑素受体。这些结果引发了一系列关于心脏起搏基本方面的问题。
