Possible Interaction: Manganese and Serotonin

“ Manganese exposure restricted to the early postnatal period caused lasting reductions in cortical potassium-stimulated extracellular norepinephrine, dopamine, and serotonin , and reductions in striatal extracellular dopamine.”

“Biochemical results show that manganese significantly decreased tissue levels of norepinephrine and serotonin with increased metabolism of dopamine in the striatum.”

“… 5-HT controls the level of excitability of postural network MNs by two mechanisms acting at two different sites: inhibitory responses (consistent with an action … initial segment region and may involve classic synaptic transmission, whereas depolarizing responses (consistent with an action involving closing of K(+) channels) occur on MN ….”

“Depressor and levator MN tonic firing rates and resistance reflex amplitudes were significantly modified in the presence of 10 μm 5-HT in dominants but not in subordinates.”

“ 5-HT increases MN excitability in several ways, including inhibition of a barium-insensitive leak conductance, inhibition of I(Kir), and enhancement of I(h).”

“ Mn exposure in either diet group resulted in a significant increase in the DA and NE levels but a decrease in the 5-HT level.”

“ Manganese decreased slow 5-HT depolarizations of both cell types.”

“Neonatal exposure to manganese (10 mg/kg X 15) produces a decrease in binding of [3H]-spiroperidol to striatal membranes and of serotonin to frontal cortical membranes.”

“Combined exposure of Mn and Cu also produced a greater elevation in the levels of dopamine (DA) and norepinephrine (NE) and a depression of 5-hydroxytryptamine (5-HT) in the brain of animals fed with a 10% casein diet compared to the animals receiving the 21% casein diet.”

“Rats exposed to manganese (20 μg/g) exhibited a significant increase in the concentration of serotonin in the hypothalamus, while levels in the corpus striatum were unaffected by the treatment.”