Whole cell Cl- currents in human neutrophils induced by cell swelling

Am J Physiol. 1993 Jul;265(1 Pt 1):C156-65. doi: 10.1152/ajpcell.1993.265.1.C156.

Abstract

The properties of the conductive Cl- transport pathway underlying regulatory volume decrease (RVD) in human neutrophils were investigated using the whole cell patch-clamp technique. Cell swelling was induced during whole cell recordings by making the patch pipette solution hyperosmotic (approximately 20%) relative to the bath by addition of sucrose. Immediately after establishment of the whole cell configuration, no measurable Cl- currents were evident. Over a period of several minutes the outwardly rectifying Cl- current that developed displayed no apparent voltage dependence of activation and did not inactivate with time during voltage steps over the range of -80 to +80 mV. Reduction of Cl- currents by application of suction to the interior of the pipette implied that the swelling-induced Cl- channels are activated by membrane stretch. Based on reversal potential measurements, the volume-induced Cl- conductance was found to discriminate poorly among Cl-, Br-, I-, and NO3-, to possess a finite permeability to glucuronate (Pglucuronate/PCl approximately 0.1) and to be impermeable to cations. Single-channel conductance was estimated to be 1.5 pS from analysis of the variance of membrane current fluctuations. The activated Cl- currents were blocked by 100 microM of the compound MK-447 analogue A (inhibitor constant Ki = 37 microM) and by 200 microM 3,5-diiodosalicylate, 500 microM 4-acetamido-4'-iodothiocyanostilbene-2,2'-disulfonic acid, and 200 microM UK-5099. These results suggest that the initial event triggering RVD in neutrophils may be activation of stretch sensitive Cl- channels in the plasma membrane.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / pharmacology
  • Acrylates / pharmacology
  • Anions / metabolism
  • Butylated Hydroxytoluene / analogs & derivatives
  • Butylated Hydroxytoluene / pharmacology
  • Chlorides / physiology*
  • Electric Conductivity
  • Humans
  • Iodobenzoates
  • Neutrophils / cytology
  • Neutrophils / metabolism*
  • Neutrophils / physiology*
  • Salicylates / pharmacology
  • Water / metabolism*

Substances

  • Acrylates
  • Anions
  • Chlorides
  • Iodobenzoates
  • Salicylates
  • Water
  • 3,5-diiodosalicylic acid
  • Butylated Hydroxytoluene
  • 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid
  • 2-cyano-3-(1-phenylindol-3-yl)acrylate
  • 2-aminomethyl-4-t-butyl-6-iodophenol