Possible Interaction: Melatonin and Norepinephrine

“In young men and women, melatonin influences vascular reactivity and reduces blood pressure and norepinephrine levels.”

“In young individuals melatonin administration reduces circulating norepinephrine.”

“ Melatonin administration significantly decreased mean PI of internal carotid artery (P < 0.02), systolic and diastolic blood pressure (P < 0.01), and norepinephrine levels evaluated after 5 min of standing position (P < 0.02).”

“Since NA stimulates the production and secretion of melatonin , these results are consistent with a sustained increase in noradrenergic activity within the pineal, during 21 days of treatment with an effective NA uptake inhibitor.”

“In particular it is suggested that NE is largely functionally opposed to 5HT, ACH, MT , and possibly DA in AD.”

“ Melatonin inhibits the 70mM K(+)-induced norepinephrine release at a similar effective concentration range in PC12 cells.”

“The molecular mechanisms of this process have … characterized as the following: nighttime release of noradrenaline in the mammalian pineal gland (which activates β-adrenergic receptors to stimulate adenylate cyclase activity … elevate cAMP) up-regulates the activity of 5-HT N-acetyltransferase and subsequently increases melatonin levels in … circadian fashion.”

“Interestingly, the effects of noradrenaline , the major neurotransmitter in the sympathetic nerve fibers, displays opposite effects on the melatonin biosynthesis in birds and mammals: it stimulates the melatonin biosynthesis in the mammalian pineal organ, but inhibits the melatonin formation in the chicken.”

“Studies have shown that oral administration of melatonin decreases blood pressure, vascular reactivity, and norepinephrine levels [5].”

“Melatonin and related compounds increase sleep by suppressing the activity of the neurons in the brain's circadian clock, and NE influences the synthesis of melatonin.”