Possible Interaction: Adenosine Triphosphate and Vitamin B 6

“On clinical application of this procedure, it was found that cirrhotic patients without hepatomas could be differentiated from those with primary hepatomas since in the former a clear reduction of AFP levels following the administration of pyridoxine and ATP took place.”

“Simultaneous injections of pyridoxine and adenosine 5'-triphosphate (ATP) resulted insignificant decreases of elevated serum AFP levels in carbon tetrachloride (CCl4)-injured rats but in 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB)-induced hepatoma-bearing rats.”

“Importantly, PL and PLP reduced IL-1β production induced by LPS and ATP , or by LPS alone, in mice.”

“Both high- and low-affinity sites for ATP binding in sarcolemmal membranes were also decreased by PLP.”

“The increase in cardiac contractile activity of isolated heart by ATP was reduced by PLP , unlike propranolol, whereas that by isoproterenol was not depressed by PLP.”

“The allosteric inhibitor, ATP , increased both the accessibility of PLP to iodide and the quantum yield, suggesting induction of a different conformational state which we term I, evidence for which has also been presented by other groups using other probes.”

“Pyridoxalphosphate-6-azophenyl-2′,4′-disulphonic acid (3–300 μM), pyridoxal 5phosphate (3–300 μM) and d-tubocurarine (30–300 μM) produced an insurmountable antagonism of responses to ATP , with no marked change in agonist EC50.”

“Furthermore, different concentrations of PLP (1-50 microM) were shown to inhibit the specific ATP gamma S binding at both the high and low affinity sites in the cardiac sarcolemmal membrane; adrenoceptor and Ca2+-channel inhibitors did not affect the ATP-binding.”

“It is concluded that PLP may antagonize the actions of ATP on the heart in a selective manner and both pyridoxal and phosphate moieties are essential for its action.”

“We report here that pyridoxal 5'-phosphate (PLP), an active form of vitamin B6, shows antagonism towards ATP-induced positive inotropic effect in … adult cardiomyocytes and ATP-binding in cardiac sarcolemma; ED50 for PLP in each of these cases varied from 10-15 microM. PLP (5-… ATP but … heart.”

“Suramin and pyridoxalphosphate‐6‐azophenyl‐2′ , 4′‐disulphonic acid (PPADS), P2 receptor antagonists, failed to inhibit the depression produced by ATP (50 μM).”

“These affects of ATP were antagonized by pyridoxal‐phosphate‐6‐azophenyl‐ 2′, 4′‐disulphonic acid (PPADS; 30 μM) but not suramin (100 μM).”

“In the presence of 10 μmol 1−1 pyridoxal‐5″‐phosphate or 30 μmol 1−1 suramin, the secretory response to ATP was reduced, but the effect of UTP was unaltered.”

“The inhibition of pyridoxal 5'-phosphate for both ATP and Ca2+ was competitive.”