title: Melastatin-type transient receptor potential channel 7 is required for intestinal pacemaking activity.
abstract: OBJECTIVE
  Interstitial cells of Cajal are pacemakers in the gastrointestinal tract, regulating rhythmicity by activating nonselective cation channels. In Caenorhabditis elegans, the melastatin-type transient receptor potential (TRPM) channel, especially TRPM7, was suggested as being involved in defecation rhythm. The aim here was to show that the nonselective cation channel in interstitial cells of Cajal in mouse small intestine has properties essentially identical to those of murine TRPM7, heterologously expressed in human embryonic kidney cells.
  
  
  METHODS
  The patch-clamp technique for whole-cell recording was used in cultured or single interstitial cells of Cajal. TRPM7-specific small interfering RNAs were used for specific inhibition of TRPM7.
  
  
  RESULTS
  Electrophysiological and pharmacological properties of the nonselective cation channel in interstitial cells of Cajal were the same as those of TRPM7. Reverse-transcription polymerase chain reaction, Western blotting, and immunohistochemistry all showed abundant and localized expression of TRPM7 messenger RNA and protein in mouse small intestine. Treatment of primary cultured interstitial cells of Cajal with TRPM7-specific small interfering RNA resulted in inhibition of pacemaking activity.
  
  
  CONCLUSIONS
  TRPM7 is required for intestinal pacemaking. The protein is a likely potential target for pharmacological treatment of motor disorders of the gut.
authors.affiliation: Department of Physiology and Biophysics, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Byung Joo
authors.initials: BJ
authors.lastname: Kim
authors.forename: Hyun-Ho
authors.initials: HH
authors.lastname: Lim
authors.forename: Dong Ki
authors.initials: DK
authors.lastname: Yang
authors.forename: Jae Yeoul
authors.initials: JY
authors.lastname: Jun
authors.forename: In Youb
authors.initials: IY
authors.lastname: Chang
authors.forename: Chul-Seung
authors.initials: CS
authors.lastname: Park
authors.forename: Insuk
authors.initials: I
authors.lastname: So
authors.forename: Peter R
authors.initials: PR
authors.lastname: Stanfield
authors.forename: Ki Whan
authors.initials: KW
authors.lastname: Kim
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000187:drug effects / Q000502:physiology*; D002413:Cations, Divalent / Q000494:pharmacology; D002460:Cell Line; D002478:Cells, Cultured; D017615:Enteric Nervous System / Q000166:cytology / Q000502:physiology*; D005260:Female; D005769:Gastrointestinal Motility / Q000502:physiology*; D015870:Gene Expression; D006801:Humans; D007422:Intestines / Q000294:innervation / Q000502:physiology; D007668:Kidney / Q000166:cytology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D018408:Patch-Clamp Techniques; D050053:TRPM Cation Channels / Q000235:genetics / Q000502:physiology*
chemical_list: D002413:Cations, Divalent; D050053:TRPM Cation Channels; C421903:Trpm7 protein, mouse