Regulation of the basolateral potassium conductance of the Necturus proximal tubule

Y. Matsumura, B. Cohen, W. B. Guggino, G. Giebisch

Research output: Contribution to journalArticle

Abstract

Two methods, the measurement of the response of the basolateral membrane potential (Vbl) of proximal tubule cells of Necturus to step changes in basolateral K+ concentration, and cellular cable analysis, were used to assess the changes in basolateral potassium conductance (GK) caused by a variety of maneuvers. The effects of some of these maneuvers on intracellular K+ activity (aKi) were also evaluated using double-barreled ion-selective electrodes. Perfusion with 0 mm K+ basolateral solution for 15 min followed by 45 min of 1 mm K+ solution resulted in a fall in basolateral potassium (apparent) transference number (tK), Vbl and aKi. Results of cable analysis showed that total basolateral resistance, Rb, rose. The electrophysiological effects of additional manipulations, known to inhibit net sodium reabsorption across the proximal tubular epithelium of Necturus, were also investigated. Ouabain caused a fall in tK accompanied by large decreases in aKi and Vbl. Lowering luminal sodium caused a fall in tK and a small reduction in Vbl. Selective reduction of peritubular sodium, a maneuver that has been shown to block sodium transport from lumen to peritubular fluid, also resulted in a significant decrease in tK. These results suggest that GK varies directly with rate of transport of the sodium pump, irrespective of the mechanism of change in pump turnover.

Original languageEnglish (US)
Pages (from-to)153-161
Number of pages9
JournalThe Journal of Membrane Biology
Volume79
Issue number2
DOIs
StatePublished - Jun 1 1984
Externally publishedYes

Keywords

  • Necturus
  • basolateral membrane
  • potassium conductance
  • proximal tubule
  • sodium-potassium pump

ASJC Scopus subject areas

  • Biophysics
  • Physiology
  • Cell Biology

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