Possible Interaction: Norepinephrine and Vitamin C

“ Ascorbic acid (ascorbate) participates in critical steps of the biosynthesis of norepinephrine , including those mediated by tyrosine hydroxylase (TH) and dopamine-β-hydroxylase (DBH).”

“As vitamin C enhances the endogenous synthesis of noradrenaline and vasopressin, and is depleted in patients with septic shock, it is certainly not implausible that vitamin C administration in this setting may improve haemodynamic instability and promote more rapid shock reversal.”

“ Ascorbic acid enhances synthesis of norepinephrine from dopamine in adrenal chromaffin cells by serving as a co-factor for chromaffin granule dopamine β-hydroxylase (DβH).”

“Co-administration of vitamin C completely restored the response to NE and to ANG II, which was comparable to that observed under baseline conditions (n = 8).”

“ Ascorbic acid has been used as an antioxidant during the hydrolysis of conjugated NA or DA.”

“Hydrolysis of NA sulfates was considerably inhibited by adding ascorbic acid (0.5-10 mM), and slightly inhibited by adding dithiothreitol (1-10 mM).”

“The marked increase in plasma conjugated DA and NA was considerably reduced after ascorbic acid treatment, presumably due to competitive inhibition of sulphate conjugation.”

“Pretreatment with N(G)-nitro-L-arginine methyl ester (L-NAME) abolished the enhanced … acetylcholine caused by vitamin C. The results suggest that the antihypertensive effect of vitamin C is associated with a … in vascular sensitivity to noradrenaline and enhancement of endothelium-dependent relaxation … to increased nitric oxide bioavailability.”

“ Vitamin C reduced the sensitivity of aortic rings to noradrenaline in rats on normal and high-sodium diets.”

“On the contrary, AA antagonised the Mn-induced DA and NA depletion.”

“The uptake of noradrenaline was inhibited by ascorbic acid (IC50 = 3.4 × 10−7 M), adrenaline (IC50 = 7.9 × 10−7 M), and dopamine (IC50 = 1.5 × 1.0−6 M).”

“These findings provide evidence that ascorbic acid may stimulate the conversion of dopamine to norepinephrine by increasing dopamine beta monooxygenase activity rather than by increasing the substrate supply of dopamine.”