Properties and regulation of basolateral K+ channels in rat duodenal crypts.

Academic Article

Abstract

  • 1. Patch clamp recording techniques were used to study the properties of K+ channels in the basolateral membrane of rat duodenal crypts, and their regulation by Cl(‐)‐secretory agonists. 2. High conductance (84‐99 pS) K+ channels were activated by 0.1 mM dibutyryl cAMP in 50% of cell‐attached patches, while 0.1 mM carbachol had no effect on channel activity. High conductance K+ channels were voltage independent, Ca2+ insensitive, blocked by 5 mM Ba2+ or 20 mM tetraethylammonium chloride (TEA), and stimulated by 57% when intracellular pH was increased from 7.4 to 7.8. 3. In contrast, low conductance (19‐28 pS) K+ channels were activated by 0.1 mM dibutyryl cAMP in 67% of cell‐attached patches, while 0.1 mM carbachol activated channels in 100% of cell‐attached patches. Low conductance K+ channels were voltage independent, Ca2+ sensitive and pH insensitive. Unlike the high conductance K+ channels, 5 mM Ba2+ had no effect on the activity of low conductance K+ channels, although 20 mM TEA decreased channel activity by 53%. 4. The results show that the basolateral membrane of rat duodenal crypts possesses two discrete populations of K+ channels that may have important roles in sustaining the small intestinal Cl(‐)‐secretory responses triggered by a variety of cAMP‐ and Ca(2+)‐mediated agonists. © 1994 The Physiological Society
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    Digital Object Identifier (doi)

    Author List

  • McNicholas CM; Fraser G; Sandle GI
  • Start Page

  • 381
  • End Page

  • 392
  • Volume

  • 477
  • Issue

  • 3