Activation of Melatonin Receptors by Ramelteon Induces Cardioprotection by Postconditioning in the Rat Heart

Activation of melatonin receptors protects the heart against ischemia-reperfusion injury. Ramelteon, a clinically used drug for insomnia, acts via activation of melatonin receptors. We investigated whether ramelteon induces acute infarct size reduction by postconditioning. Male Wistar rats were randomized to 6 groups. Hearts were treated with melatonin and ramelteon at the beginning of reperfusion. The melatonin receptor inhibitor luzindole was administered with and without melatonin and ramelteon, respectively. Ramelteon reduced infarct size to the same extent as melatonin. Both effects were completely abolished by luzindole. The results show for the first time that ramelteon induces cardioprotection by postconditioning. Accepted for publication September 27, 2017. Funding: This work was supported by departmental funding only. The authors declare no conflicts of interest. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's website (http://ift.tt/KegmMq). Reprints will not be available from the authors. Address correspondence to Ragnar Huhn, MD, PhD, Department of Anesthesiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf, Germany. Address e-mail to Ragnar.Huhn@med.uni-duesseldorf.de. © 2018 International Anesthesia Research Society

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