ABSTRACT
Melatonin, best known for its effects against jet-lag, is secreted by the pineal gland. It acts mainly via its specific receptors located in various organs, including the heart and brain. At a molecular level, melatonin acts on mitochondria to counter the adverse effect of mitochondria caused by calcium overload. Melatonin inhibits the mitochondrial permeability transition pore of threatened brain cells to lessen activation of the potentially lethal enzyme caspase-3. At an organ level, melatonin protects hearts from model heart attacks and, at higher concentrations, lessens brain damage resulting from cerebral artery occlusion. A novel antidepressant drug, agomelatine, stimulates melatonin receptors and might have organ protective effects in humans.
Notes
*Based on a talk given to the Royal Society of South Africa