Differential expression of ionic conductances in interstitial cells of Cajal in the murine gastric antrum

J Physiol. 2008 Feb 1;586(3):859-73. doi: 10.1113/jphysiol.2007.140293. Epub 2007 Nov 22.

Abstract

Two distinct populations of interstitial cells of Cajal (ICC) exist within the tunica muscularis of the gastric antrum, and these cells serve different physiological functions. One population of ICC generates and actively propagates electrical slow waves, and the other population of ICC is innervated by excitatory and inhibitory motor neurons and mediates enteric motor neurotransmission. In spite of the key role of ICC in gastric excitability, little is known about the ionic conductances that underlie the functional diversity of these cells. In the present study we isolated ICC from the murine gastric antrum and investigated the Ca(2+)-dependent ionic conductances expressed by these cells using the patch clamp technique. Conductances in ICC were compared with those expressed in smooth muscle cells. The cells studied were identified by RT-PCR using cell-specific primers that included Myh11 (smooth muscle cells), Kit (ICC) and Uchl1 (enteric neurons) following electrophysiolgical recordings. Distinct ionic conductances were observed in Kit-positive cells. One group of ICC expressed a basal non-selective cation conductance (NSCC) that was inhibited by an increase in [Ca(2+)](i) in a calmodulin (CaM)-dependent manner. A second population of ICC generated spontaneous transient inward currents (STICs) and expressed a basal noisy NSCC that was facilitated by an increase in [Ca(2+)](i) in a CaM-dependent manner. The [Ca(2+)](i)-facilitated NSCC in ICC was blocked by the Cl(-) channel antagonists 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS), anthracene-9-carboxylate (9-AC) and niflumic acid. These data suggest that distinct NSCC are expressed in subpopulations of ICC and these conductances may underlie the functional differences of these cells within the gastric antrum.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / pharmacology
  • Animals
  • Anthracenes / pharmacology
  • Calcium / metabolism
  • Chloride Channels / antagonists & inhibitors
  • Chloride Channels / metabolism
  • Ion Channels / metabolism*
  • Membrane Potentials / physiology
  • Mice
  • Mice, Inbred BALB C
  • Motor Neurons / metabolism
  • Myenteric Plexus / cytology
  • Myenteric Plexus / metabolism*
  • Myocytes, Smooth Muscle / cytology
  • Myocytes, Smooth Muscle / metabolism*
  • Patch-Clamp Techniques
  • Potassium / metabolism
  • Proto-Oncogene Proteins c-kit / metabolism
  • Pyloric Antrum / cytology
  • Pyloric Antrum / innervation
  • Pyloric Antrum / metabolism*

Substances

  • Anthracenes
  • Chloride Channels
  • Ion Channels
  • 9-anthroic acid
  • Proto-Oncogene Proteins c-kit
  • 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid
  • Potassium
  • Calcium