Cl- channels in basolateral renal medullary vesicles IX. Channels from mouse MTAL cell patches and medullary vesicles

W. B. Reeves, C. J. Winters, D. M. Filipovic, T. E. Andreoli

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

The experiments reported herein compared Cl- channels fused into bilayers from rabbit outer medullary vesicles with Cl- channels in excised patches of basolateral membranes from cultured mouse medullary thick ascending limb (MTAL) cells and evaluated whether the latter were plausible candidates for the Cl- channels mediating net NaCl absorption in microperfused mouse MTAL segments. The unique signature characteristics of Cl- channels incorporated into lipid bilayers from outer medullary vesicles include activation of open probability (P(o)) by increases in the Cl- concentrations bathing intracellular faces; activation of P(o) by protein kinase A (PKA) + ATP, when the Cl- concentrations bathing intracellular faces are low; and no effect of PKA + ATP on P(o) with high cytoplasmic-face Cl- concentrations. These same properties were observed in Cl- channels studied using excised patches of basolateral membranes from mouse MTAL cells. Moreover, in both bilayers and in excised patches, the sharpest fractional increase in Cl- channel P(o) occurred with cytosolic-face Cl- concentration increases to values similar to the antidiuretic hormone (ADH)-dependent values of intracellular Cl- activity in microperfused mouse MTAL segments, and these fractional P(o) increases were adequate to account quantitatively for the ADH-dependent increase in basolateral membrane Cl- conductance in microperfused mouse MTAL segments. Thus the excised-patch basolateral Cl- channels reported here are reasonable candidates for those mediating net Cl- absorption in the MTAL.

Original languageEnglish (US)
Pages (from-to)F621-F627
JournalAmerican Journal of Physiology - Renal Fluid and Electrolyte Physiology
Volume269
Issue number5 38-5
DOIs
StatePublished - 1995
Externally publishedYes

Keywords

  • chloride ion channels
  • medullary thick ascending limb
  • patch clamping

ASJC Scopus subject areas

  • Physiology

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