Effect of amiloride and bumetanide on transepithelial ion transport in isolated rabbit cecal and colonic wall.
BACKGROUND
The aim of the study was to compare the effects of amiloride and bumetanide on the baseline transepithelial electrical potential difference (PD) and changes in PD during mechanical stimulation (dPD) in isolated cecal and colonic wall of rabbits.


METHODS
The experiments were performed with a modified Ussing chamber system. Isolated tissue specimens were incubated in Ringer's solution, in amiloride and/or bumetanide, or in dimethyl sulfoxide (DMSO).


RESULTS
Under control conditions, i.e. when all the experimental fluids were Ringer's solution, the PD and R values of the rabbit cecum and colon were similar, while during mechanical stimulation, dPD of the colon was twice as high as that of the cecum. Addition of amiloride and/or bumetanide to all experimental fluids diminished the electrophysiological parameters of both tissues. DMSO added to all experimental fluids significantly diminished the values of the electrophysiological parameters of the cecum. Addition of amiloride to the stimulation fluid only diminished the PD and dPD values in the colon, whereas addition of bumetanide to the stimulation fluid only diminished the PD and dPD values in the cecum. It was found that the PD and dPD values of the rabbit cecum depend primarily on chloride ion transport, while those of the colon depend on sodium ion transport.
Kosik-Bogacka
Danuta
D
Department of Biology and Medical Parasitology, Pomeranian Medical University, Szczecin, Poland. kodan@sci.pam.szczecin.pl
Młodzik-Danielewicz
Natalia
N
Banach
Bolesław
B
Tyrakowski
Tomasz
T
D000584:Amiloride / Q000494:pharmacology*; D000818:Animals; D002034:Bumetanide / Q000494:pharmacology*; D002432:Cecum / Q000378:metabolism*; D018118:Chloride Channels / Q000378:metabolism*; D003106:Colon / Q000378:metabolism*; D004558:Electric Stimulation; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000378:metabolism*; D017136:Ion Transport / Q000187:drug effects; D018408:Patch-Clamp Techniques; D011817:Rabbits; D026941:Sodium Channel Blockers / Q000494:pharmacology; D015222:Sodium Channels / Q000378:metabolism*; D049994:Sodium Potassium Chloride Symporter Inhibitors / Q000494:pharmacology
D018118:Chloride Channels; D026941:Sodium Channel Blockers; D015222:Sodium Channels; D049994:Sodium Potassium Chloride Symporter Inhibitors; D002034:Bumetanide; D000584:Amiloride