Ion transport across the cecum in normal and colitic mice.
This study was conducted to determine the ion transport mechanisms in the normal mouse cecum and compare them to an inbred mouse model of colitis. The Ussing chamber-voltage clamp technique was used to monitor the short circuit current (I(sc)). The basal I(sc) in the normal cecum was 82.6 +/- 5.8 microA/cm2. It was not affected by bumetanide, 9-anthracene carboxylate, amiloride, and phenamil or by removal of Cl- ions; but was abolished by the removal of Na+ ions. Flux measurements revealed the presence of neutral NaCl transport. In the colitic cecum, the basal current was significantly higher than the normal cecum. Basal current in the normal cecum was due primarily to Na+ absorption through a Na+ channel, while in the colitic cecum it was due to Cl- ion secretion. cAMP addition in colitic cecum did not increase Cl- secretion, further suggesting that the tissue is already secreting at a maximal rate.
Homaidan
F R
FR
Department of Physiology, American University of Beirut, New York, New York 10022, USA.
Tripodi
J
J
Cheng
P
P
Donovan
V
V
Burakoff
R
R
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002432:Cecum / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D003092:Colitis / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D004553:Electric Conductivity; D005260:Female; D017136:Ion Transport; D051379:Mice; D008809:Mice, Inbred C3H; D018727:Muscarinic Antagonists / Q000494:pharmacology; D012016:Reference Values; D013779:Tetrodotoxin / Q000494:pharmacology
D018727:Muscarinic Antagonists; D015124:8-Bromo Cyclic Adenosine Monophosphate; D013779:Tetrodotoxin; D001285:Atropine