Subtractive hybridization unravels a role for the ion cotransporter NKCC1 in the murine intestinal pacemaker.
In the small intestine, interstitial cells of Cajal (ICC) surrounding the myenteric plexus generate the pacemaking slow waves that are essential for an efficient intestinal transit. The underlying molecular mechanisms of the slow wave are poorly known. Our aim was to identify ICC-specific genes and their function in the mouse jejunum. Suppression subtractive hybridization using two independent ICC-deficient mouse models identified 56 genes putatively downregulated in the muscularis propria compared with wild-type littermates. Differential expression was confirmed by real-time quantitative PCR for the tyrosine kinase receptor KIT, the established marker for ICC, and for the Na(+)-K(+)-2Cl(-) cotransporter (NKCC1). Immunoreactivity for NKCC1 was detected in myenteric ICC but not in the ICC population located at the deep muscular plexus. NKCC1 was also expressed in enteric neurons and mucosal crypts. Bumetanide, an NKCC1 inhibitor, reversibly affected the shape, amplitude, and frequency of the slow waves. Similar alterations were observed in NKCC1 knockout mice. These data support the hypothesis that NKCC1 expressed in myenteric ICC is involved in the mechanism of slow waves in the murine jejunum.
Wouters
Mira
M
Laboratoire de Neurophysiology, Faculté de Médecine, Université Libre de Bruxelles, Brussels, Belgium.
De Laet
Ann
A
Donck
Luc Ver
LV
Delpire
Eric
E
van Bogaert
Pierre-Paul
PP
Timmermans
Jean-Pierre
JP
de Kerchove d'Exaerde
Alban
A
Smans
Karine
K
Vanderwinden
Jean-Marie
JM
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D002478:Cells, Cultured; D017403:In Situ Hybridization; D007421:Intestine, Small / Q000502:physiology*; D051379:Mice; D008822:Mice, Transgenic; D032389:Myocytes, Smooth Muscle / Q000502:physiology*; D028021:Sodium-Potassium-Chloride Symporters / Q000378:metabolism*; D064506:Solute Carrier Family 12, Member 2
C578878:Slc12a2 protein, mouse; D028021:Sodium-Potassium-Chloride Symporters; D064506:Solute Carrier Family 12, Member 2