Possible Interaction: Niacin and Norepinephrine

“Hoffer, et al (3) suggested that the schizophrenic process was due to a defect in transmethylation, and that the administration of a potent methyl acceptor, such as nicotinic acid or nicotinamide, would compete with norepinephrine for free methyl groups.”

“In concentrations where nicotinic acid almost completely blocked the lipolytic actions of noradrenaline or theophylline, nicotinic acid also blocked the increasing action of the drugs on the cyclic AMP level.”

“ Nicotinic acid blocked or reduced the submaximally lipolytic effect of both noradrenaline and theophylline ; the effect of theophylline being most sensitive to nicotinic acid inhibition.”

“ Nicotinamide loading induced a significant increase in the levels of plasma N1-methylnicotinamide and norepinephrine , and a significant decrease in the levels of O-methylated epinephrine (metanephrine) and betaine, a major methyl donor, in both hypertensives and normotensives.”

“As a control a second NA infusion was given after pretreatment with nicotinic acid which blocks the release of FFA.”

“We recently found reduced renal vascular reactivity to angiotensin II (ANG II), endothelin-1 (ET-1), and norepinephrine NE ) in the presence of the broad ADPR cyclase inhibitor nicotinamide.”

“Using a rat model of isolated perfused hindlimb, we tested whether this metabolite of nicotinamide is able to inhibit the vasoconstrictive effects of epinephrine, norepinephrine , and angiotensin II, thereby releasing prostacyclin from the endothelium.”

“However, in the cortical areas, all antagonists inhibited the nicotine-induced increase of serotonin to varying degrees; and some, primarily nicotinic and dopamine D1 antagonists, inhibited the induced increase of norepinephrine.”

“The pressor effect of noradrenaline was largely diminished by 3-HAA, PA and NA.”

“In the central nervous system there are several instances of muscarinic and nicotinic modulation of dopamine and noradrenaline release (Clarke et al., 1996; DeKlippel et al., 1993; P. Izurieta-Sanchez et al, 2000; Smolders et al., 1997).”

“Both of the nicotinic agonists stimulated norepinephrine release in synaptosomes, and the effect of metanicotine was blocked at lower concentrations of &agr;4&bgr;2*- than &agr;7*-preferring nAChR antagonists.”