Sodium+,Potassium+-ATPase inhibitors

Extrapolating from well-characterized enzymatic inhibition in test tubes, numerous mechanistic ideas concerning the in vivo effects of vanadium compounds have been advanced. The effects of vanadium compounds as transition-state analogs of certain enzymes with a phosphoprotein intermediate in their reaction scheme is proposed to account for the action of vanadium [11] in many biological systems. Unfortunately, it is often difficult to determine if the inhibition observed in the test tube occurs in vivo. For example, although vanadate is a potent inhibitor of plasma membrane ion pumps (such as the sodium potassium ATPase) in the test tube, it is difficult to determine if these pumps are actually inhibited in animals exposed to vanadium compounds. Currently, the role of vanadium compounds as protein phosphatase (PTP) inhibitors is believed to be related to the metabolic effects of this... 

Cantley, L.C., Jr., L. Josephson, R. Warner, M. Yanagisawa, C. Lechene, and G. Guidotti. 1977. Vanadate is a potent (sodium, potassium ion)-dependent ATPase inhibitor found in ATP derived from muscle. J. Biol. Chem. 252 7421-3. 

Loop diuretics (e.g. ethacrynic add, bumetanide, frusemide) have a vigorous action on the ascending tubules of the loop of Henle (inhibiting resorption of sodium and water, and also some potassium), and are used for short periods, especially in heart failure. See ATPASE INHIBITORS. 

There is reason to beheve that cardiac glycosides, like other inotropic substances, act on the contractibility of the heart by affecting the process of calcium ion transfer through the membrane of myocardiocytes. The effect of cellular membranes in electric conductivity is mediated by transport of sodium, calcium, and potassium ions, which is a result of indirect inhibitor action on the (Na+-K+) ATPase of cell membranes. 

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