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Inflammatory modulation of calcium-activated potassium channels in canine colonic circular smooth muscle cells. Gastroenterology 1999 Apr;116(4):884-92

Date

03/26/1999

Pubmed ID

10092310

DOI

10.1016/s0016-5085(99)70071-5

Scopus ID

2-s2.0-0032998301   25 Citations

Abstract

BACKGROUND & AIMS: The characteristics of colonic circular smooth muscle slow waves are altered during inflammation. The aim of this study was to examine whether inflammation modulates the open-state probability of Ca2+-activated K+ (KCa) channels in these cells to contribute to these alterations.

METHODS: The experiments were performed on freshly dissociated single smooth muscle cells from the canine colon using standard patch clamp methods. Inflammation was induced by mucosal exposure to ethanol and acetic acid.

RESULTS: Inflammation decreased the open-state probability of large-conductance KCa (BK) channels in the cell-attached and excised inside-out configurations. The voltage sensitivity of the channels was also reduced during inflammation. Inflammation had no significant effect on the large, medium, and small conductances or the unitary current levels of channel openings. However, it decreased the maximum number of simultaneous channel openings. The channels were Ca2+-dependent and were blocked by tetraethylammonium and charybdotoxin in normal and inflamed cells.

CONCLUSIONS: Inflammation decreases the open-state probability of BK channels. This may partially reverse the decrease in duration and amplitude of slow waves and depolarization of membrane potential seen in inflammation.

Author List

Lu G, Mazet B, Sun C, Qian X, Johnson CP, Adams MB, Roman RJ, Sarna SK

Author

Christopher P. Johnson MD Professor in the Surgery department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Calcium
Colitis
Colon
Dogs
Muscle, Smooth
Peroxidase
Potassium Channels
Probability
jenkins-FCD Prod-478 d1509cf07a111124a2d122fd3df854cc0b993c00