Evidence of the Strong Cardiac Rhythmicity-enhancing Power of Melatonin in the Drosophila melanogaster Model System

This review's goal is to provide a summary of the strong evidence for melatonin's ability substantially to improve cardiac rhythmicity in the Drosophila melanogaster model system and to discuss the implications of these findings in relation to the fundamental mechanism cardiac pacemakers with potential clinical applications. Given the extensive genetic and molecular resources it provides, Drosophila has distinguished itself as a top study organism with wide relevance. We discuss the extensive work reported on the myogenic, ion-channel-based pacemaker of the fly and provide an overview of its neurohomonal regulation. Our most recent work greatly extends the few studies noting melatonin's ability to enhance cardiac rhythmicity. Melatonin is used clinically in cardiology owing to its antioxidant properties as a protection against reperfusion damage after infarct. We discuss our clear results showing that melatonin is also capable of converting normal noisy heartbeat to an extremely regular oscillator. It completely rescues the highly erratic beat of the hearts of flies bearing a serious mutation in a gene encoding one of its core pacemaker ion channels. Possible mechanisms for these effects are considered.