[Anti-hypertensive action of melatoninergic compounds]

Melatonin synchronizes circadian rhythms with light/dark period and it was demonstrated to correct chronodisruption. The night time rise in endogenous circulating melatonin levels is also inversely related to the reduction in night time blood pressure. The chronic administration of melatonin to individuals with hypertension induces a measurable drop in night time systolic and diastolic blood pressure. Moreover, the higher the night time level of endogenous melatonin (estimated from urinary metabolite of melatonin, 6-hydroxymelatonin sulphate), the greater the reduction in arterial blood pressure at night. The implication of these findings is that melatonin may have utility as an anti-hypertensive agent. Previous data have suggested that cardiovascular effects of melatonin are at least partly mediated via MT(1)/MT(2) receptors and associated with its chronobiotic action. Therefore, although anti-hypertensive action of melatonin is not so dramatic, it is believed that these effects will be shared by melatonin receptor agonists as well. Considering this, the investigation of cardiovascular effects of melatoninergic compounds should no longer be neglected.