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Reduction of Vanadate by Ascorbic Acid and Noradrenaline in Synaptosomes
Author(s) -
ÁdámVizi Vera,
Váradi G.,
Simon P.
Publication year - 1981
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1981.tb00410.x
Subject(s) - vanadate , ascorbic acid , chemistry , vanadium , biochemistry , reducing agent , atpase , inorganic chemistry , enzyme , organic chemistry , food science
The effect of ascorbic acid and noradrenaline on the inhibition of synaptosomal membrane ATPase by vanadate has been studied. Ascorbic acid (2 × 10 ‐3 M) and noradrenaline (10 ‐4 M) partly reversed the inhibition by vanadate (10 ‐6 M); however, when both were administered together the inhibition was completely eliminated. Using electron spin resonance (ESR) spectroscopy, we detected that ascorbic acid (10 ‐3 M) caused a 42% of reduction of vanadate (10 ‐4 M). Noradrenaline (10 ‐4 M) alone also reduced vanadate (10 ‐4 M) partially. When ascorbic acid and noradrenaline were present together all the vanadate was reduced to vanadyl. The concentration of ascorbic acid present in the brain under physiological conditions is identical to that found effective in our experiments. We suggest that ascorbic acid may protect the ATPase, at least in part, from inhibition by vanadate as a consequence of reducing vanadate to vanadyl. In those tissues where noradrenaline is also present a complete reduction of endogenous vanadium can be presumed.