Inwardly rectifying chloride channel activity in intestinal pacemaker cells

Yaohui Zhu, Andrea Mucci, Jan D. Huizinga

Research output: Contribution to journalArticlepeer-review

Abstract

Cl- channels are proposed to play a role in gut pacemaker activity, but little is known about the characteristics of Cl- channels in interstitial cells of Cajal (ICC), the intestinal pacemaker cells. The objective of the present study was to identify whole cell Cl- currents in ICC associated with previously observed single-channel activity and to characterize its inward rectification. Whole cell patch-clamp studies showed that ICC express an inwardly rectifying Cl- current that was not sensitive to changes in cation composition of the extracellular solutions. Currents were not affected by replacing all cations with N-methyl-D-glucamine (NMDG+). Whole cell currents followed the Cl- equilibrium potential and were inhibited by DIDS and 9-anthracene carboxylic acid. Ramp protocols of single-channel activity showed that inward rectification was due to reduction in single-channel open probability, not a reduction in single-channel conductance. Single-channel data led to the hypothesis that strong cooperation exists between 30-pS channels that show less cooperation at potentials positive to the reversal potential. Hence, an inwardly rectifying Cl- channel plays a prominent role in determining pacemaker activity in the gut.

Original languageEnglish (US)
Pages (from-to)G809-G821
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume288
Issue number4 51-4
DOIs
StatePublished - Apr 2005
Externally publishedYes

Keywords

  • Gastrointestinal motility
  • Interstitial cells of Cajal
  • Pacemaking activity

ASJC Scopus subject areas

  • Physiology
  • Hepatology
  • Gastroenterology
  • Physiology (medical)

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