The Impact of Melatonin and its Agonist on Endothelin-1 Reactivity in Isolated Aorta in Continuous Light and Pinealectomized Rats

Autor: Evan B. Othman, Ismail M. Maulood
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Zanco Journal of Pure and Applied Sciences, Vol 35, Iss 2 (2023)
Druh dokumentu: article
ISSN: 2218-0230
2412-3986
DOI: 10.21271/ZJPAS.35.2.19
Popis: The purpose of the present study is to investigate the influence of melatonin and its receptor (MT1, and MT2) agonist (Ramelteon) on vascular endothelin-1 (ET-1) reactivity in isolated aortic rings in continuous light emitting diode (LED) exposure and pinealectomized rats. Materials and Methods: Two sets of experiments were performed in this study. In the first experiment, animals were divided into four groups: (control, continuous LED exposure rats, continuous light + Melatonin administration, and continuous light + Ramelteon administration). In the second experiment, animals were categorized into five groups: Control, rats underwent pinealectomy, pinealectomy + Melatonin administration, pinealectomy + Ramelteon administration, and pinealectomy + a continuous LED exposure. Results: The obtained results indicated that in constant light exposure of the rats for 10 weeks, the ET-1-induced aortic ring contraction was markedly reduced.Conversely, melatonin and its agonist (Ramelteon) markedly elevated the ET-1-induced aortic ring contraction. Neither, melatonin nor its agonist supplementation significantly increased ET-1 Emax. Similarly, in the second experiment after 6 weeks of pinealectomy and pinealectomy with continuous light exposure to rats significantly decreased aortic ring contraction. Moreover, ET-1 Emax significantly and ET-1 efficiency and AUC were slightly elevated in pinealectomy with light exposure group compared to the pinealectomized rats. On the other hand, ramelteon shifted the DRC of ET-1 to the left side. Conclusion: The results suggested that most of the melatonin actions on vascular modulation are due to its binding to MT1and MT2 receptors.
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