Possible Interaction: Dopamine and Melatonin

“The antagonism of melatonin in models of Parkinson's disease (PD) can reduce the severity of motor impairment associated with dopamine (DA) degeneration.”

“Plasma norepinephrine and dopamine levels in the supine position 60 minutes after melatonin administration were lower compared with placebo (P <.05 and P <.01, respectively).”

“There is some evidence in animals that dopamine DA ) affects melatonin secretion.”

“In accordance with changes in the expression levels of enzymes, dopamine production and cAMP synthesis determined in the culture medium and cell lysate were also suppressed by melatonin.”

“ Melatonin inhibits the release of dopamine from amacrine cells and increases the light sensitivity of horizontal cells.”

“ Dopamine and adrenergic receptor complexes form under a circadian-regulated cycle and directly modulate melatonin synthesis and release from the pineal gland.”

“ Dopamine and adrenergic receptor complexes form under a circadian-regulated cycle and directly modulate melatonin synthesis and release from the pineal gland.”

“In Parkinson patients melatonin may, on the one hand, exacerbate symptoms (because of its putative interference with dopamine release ) and, on the other, protect against neurodegeneration (by virtue of its antioxidant properties and its effects on mitochondrial activity).”

“Inhibition of dopamine release by melatonin has been demonstrated in specific areas of the mammalian central nervous system (hypothalamus, hippocampus, medulla-pons, and retina).”

“ Melatonin … [3H]dopamine release by 50% (IC50) at 20 pM with a maximal inhibitory effect (80%) at 1 nM. The partial agonists, i.e., N-acetyltryptamine (… inhibition 40%) showed various degrees of efficacy while none of the competitive melatonin receptor antagonists did inhibit [3H]dopamine release on their own.”

“Surprisingly, only the stimulatory effect of dopamine could be inhibited by exposure to melatonin.”