This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (58) Citing Articles via Google Scholar Google Scholar Articles by Cheeseman, J. M. Articles by Hanson, J. B. Search for Related Content PubMed PubMed Citation Articles by Cheeseman, J. M. Articles by Hanson, J. B. Agricola Articles by Cheeseman, J. M. Articles by Hanson, J. B.

Articles

Effect of ATPase Inhibitors on Cell Potential and K⁺ Influx in Corn Roots ¹

Department of Botany, University of Illinois, Urbana, Illinois 61801

Experiments were performed to determine the effect of plasmalemma ATPase inhibitors on cell potentials () and K⁺ (⁸⁶Rb) influx of corn root tissue over a wide range of K⁺ activity. N,N'Dicyclohexylcarbodiimide (DCCD), oligomycin, and diethylstilbestrol (DES) pretreatment greatly reduced active K⁺ influx and depolarized at low, but not at high, K⁺ activity (K°). More comprehensive studies with DCCD and anoxia showed nearly complete inhibition of the active component of K⁺ influx over a wide range of K°, with no effect on the apparent permeability constant. DCCD had no effect on the electrogenic component of the cell potential (_p) above 0.2 millimolar K°. Net proton efflux was rapidly reduced 80 to 90% by DCCD. Since tissue ATP content and respiration were only slightly affected by the DCCD-pretreatment, the inhibitions of active K⁺ influx and _p at low K° can be attributed to inhibition of the plasmalemma ATPase.

It is concluded that by DCCD treatment, the energy-linked electrogenic system at high K° is separated from the energy-linked K⁺ influx system at low K°. The results are analyzed in terms of electrical analogue models of the membrane. The presence of two, algebraically additive electrogenic components is indicated; one is better modeled as a current source (system I) and one as a voltage source (system II). No K⁺ stimulation of system II is required to produce the observed K° dependence of _p.

This article has been cited by other articles:

				F. Rubio, M. Schwarz, W. Gassmann, and J. I. Schroeder Genetic Selection of Mutations in the High Affinity K+ Transporter HKT1 That Define Functions of a Loop Site for Reduced Na+ Permeability and Increased Na+ Tolerance J. Biol. Chem., March 12, 1999; 274(11): 6839 - 6847. [Abstract] [Full Text] [PDF]