Basolateral K+ conductances in surface epithelium of Necturus antrum: Effects of Ca2+ and divalent cations

David Soybel, S. W. Ashley, L. Y. Cheung

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Intracellular microelectrode techniques were used to characterize basolateral membrane K+ conductances in isolated Necturus antral mucosa. Exposure of tissues to progressively higher levels of serosal K+ (4, 20, 40, or 60 mM) resulted in progressively greater depolarizations of basolateral membrane potentials and decreases in membrane resistance, consistent with the presence of a significant K+ conductance. Ba2+ (2 mM) partially blocks these conductances. Exposure of tissues to increased levels of serosal Ca2+ (from 1.8 to 6.8 mM) elicited significant hyperpolarization of basolateral potentials and decreases in basolateral resistance. These effects are also elicited by Sr2+ (5 mM), but not by Mg2+ (5 mM). Ba2+ (5 mM) elicits complex and time-dependent effects, but transiently elicits an effect similar to high Ca2+. Ion substitutions in the serosal perfusate suggest that the Ca2+-induced effects are due to enhancement of basolateral K+ conductances. Further work is necessary to identify the processes that mediate this increase in basolateral K+ conductance and to evaluate the physiological significance of this change in membrane permeability to K+.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume262
Issue number4 25-4
StatePublished - Jan 1 1992

All Science Journal Classification (ASJC) codes

  • Physiology
  • Hepatology
  • Gastroenterology
  • Physiology (medical)

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