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Effects on fluid and Na+ flux of varying luminal hydraulic resistance in rat colon in vivo.
Author(s) -
Zammit P S,
Mendizabal M,
Naftalin R J
Publication year - 1994
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1994.sp020214
Subject(s) - agarose , chemistry , in vivo , chromatography , absorption (acoustics) , tonicity , electrolyte , absorption of water , materials science , biochemistry , biology , composite material , microbiology and biotechnology , electrode
1. A new method of measuring fluid and ionic movements and the dehydrating power of the colon in vivo is described. A range of agarose gel cylinders, with calibrated hydraulic conductivities (Lp), were inserted into the lumen of the descending colon of anaesthetized rats. Fluxes of fluid, Na+ and K+ out of the gels were measured over a period of 60‐110 min. 2. Fluid absorption by the colon from 2.5% agarose gels was not slower than from solution without gel. Fluid absorption was inhibited by 66% when the agarose concentration was raised to 10%. In contrast 2.5% agarose gels caused a 73% (P < 0.001) reduction in water flow from rat ileum. 3. Increasing gel concentration to 10% or above caused the absorbate from the gels to become hypertonic (P < 0.001). 4. The measured suction pressure applied by the colonic hypertonic absorbate to the gels increased from 44 +/‐ 2.3 cmH2O (n = 23) with 2.5% agarose gels to 6713 +/‐ 960 cmH2O (n = 13) with 15% (P < 0.001). 5. Deoxycholate (2 mM) produced a decrease in fluid and Na+ absorption and reduced the suction pressure and power exerted by the colon.