Antifibrilatory Potential of Melatonin

**49**

effects.

**Chapter 4**

**Abstract**

applications.

**1. Introduction**

tomorrow.

connexin 43, melatonin receptors

Rhythm

Melatonin for a Healthy Heart

*Natalia Jorgelina Prado, Margarita Segovia-Roldan,* 

Melatonin is a promising cardioprotective agent. Its increase during the night is associated with healthy cardiovascular function. On the other hand, reduced levels of melatonin are related to diseases. Aging and chronodisruptors reduce melatonin levels. Pharmacological supplementation reduces the deleterious effects of cardiovascular risk factors and improves the myocardial response to ischemia/ reperfusion injury and other proarrhythmic conditions. The protective mechanisms of melatonin involve its antioxidant properties as well as receptor-mediated actions. Signaling pathways include membrane responses, cytoplasmic modulation of kinases, nuclear receptor interactions, and improvement of mitochondrial functions. This chapter focuses on the electrophysiological and the antiarrhythmic properties of melatonin. The acute and chronic protective mechanisms of melatonin will be analyzed with an emphasis on transmembrane potentials and intercellular communication. An outstanding antifibrillatory effect makes melatonin a novel antiarrhythmic agent worthy of further exploration in the path to clinical

**Keywords:** melatonin, arrhythmias, ventricular fibrillation, action potential,

"Nothing to do to save his life…" says the Beatles song "Good morning, good morning." Ironically, cardiovascular mortality and life-threatening arrhythmias show a circadian increase in the mornings, and chronoprotective agents are still missing [1, 2]. This chapter highlights the importance of melatonin as a potential life-saving agent for the darkest nights (of antiarrhythmics drugs) and a brightest

The cardioprotective properties of melatonin are remarkable. Most of the preclinical and clinical studies support the protective actions and the safety profile of this indolamine [3, 4]. In this chapter, we briefly introduce the multitarget and versatile properties of melatonin and general concepts of electrophysiology to appreciate its potential as a promising antiarrhythmic agent. The second and third sections of the chapters focus on acute and chronic melatonin's antiarrhythmic

*Emiliano Raúl Diez and Esther Pueyo*
