Pacemaker activity from submucosal interstitial cells of Cajal drives high-frequency and low-amplitude circular muscle contractions in the mouse proximal colon

Neurogastroenterol Motil. 2004 Oct;16(5):621-7. doi: 10.1111/j.1365-2982.2004.00546.x.


The present study was aimed at elucidating how pacemaker activity (plateau potentials) (mean frequency: 15.9 +/- 2.8 times min(-1)) from submucosal interstitial cells of Cajal (ICC-SM) control spontaneous contractions in the mouse proximal colon. Mechanical activities in the circular muscle direction showed high-frequency (mean frequency: 15.6 +/- 2.7 times min(-1)) and low-amplitude (mean amplitude: 0.01 +/- 0.005 g) (HFLA) rhythmic contractions. Simultaneous recordings of circular muscle mechanical activity and electrical activity from ICC-SM revealed that HFLA contractions were synchronized with plateau potentials (mean frequency: 15.9 +/- 2.8 times min(-1)). Although low-frequency (3.5 +/- 2.1 times min(-1)) and high-amplitude (0.12 +/- 0.03 g) (LFHA) contractions in both longitudinal and circular muscle directions were synchronized with burst of action potentials in both muscle cells, these LFHA contractions were not synchronous with plateau potentials. Intracellular Ca2+ release from the internal stores through IP3 receptors is not a major factor to generate both action potentials differently from plateau potentials. Neither tetrodotoxin nor atropine affected the plateau potentials. The results reveal that the pacemaker activity from ICC-SM drives only the spontaneous HFLA (one-tenth amplitude of the LFHA circular and longitudinal muscle contractions) circular muscle contractions without control by enteric nerves.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Clocks / physiology*
  • Calcium / metabolism
  • Calcium Channels / metabolism
  • Colon / cytology*
  • Colon / physiology
  • Inositol 1,4,5-Trisphosphate Receptors
  • Intestinal Mucosa / cytology*
  • Intestinal Mucosa / physiology
  • Male
  • Membrane Potentials / physiology*
  • Mice
  • Mice, Inbred BALB C
  • Microelectrodes
  • Muscle, Smooth / physiology*
  • Organ Culture Techniques
  • Receptors, Cytoplasmic and Nuclear / metabolism


  • Calcium Channels
  • Inositol 1,4,5-Trisphosphate Receptors
  • Receptors, Cytoplasmic and Nuclear
  • Calcium