Sorption of potassium in the small and the large intestine

Sf, Phillips; Cf, Code

doi:10.1152/ajplegacy.1966.211.3.607

Cited by 47 publications

(18 citation statements)

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“…This relationship can be described by the Hodgkin & Katz (1949) Thus the mucosal membrane of the intestinal epithelial cell is permeable to both sodium and potassium ions, being slightly more permeable to potassium. This relatively high permeability of the mucosal membrane is not consistent with the low potassium fluxes which have been observed across the dog small intestine (Phillips & Code, 1966). This discrepancy could be explained if a mechanism for the uptake of potassium into the cell exists at the mucosal membrane.…”

Section: Discussioncontrasting

confidence: 63%

Ionic basis of membrane potentials of epithelial cells in rat small intestine

Barry¹,

Eggenton²

1972

The Journal of Physiology

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SUMMARY1. Potentials across the mucosal and serosal membranes of the epithelial cells of rat jejunum together with transmural potentials were recorded using everted sac preparations.2. Ionic changes in either mucosal or serosal fluids affect mucosal or serosal membrane potentials respectively with comparable changes in the transmural potential. The contralateral membrane potential is relatively unaffected.3. Replacement of mucosal sodium chloride by potassium chloride or lithium chloride had little effect on potentials, but its replacement by mannitol or Tris chloride increased the negativity of the mucosal potential, 5. Qualitatively similar changes occurred in the serosal potential when the ionic composition of the serosal fluid was varied.6. Mucosal potential changes in response to modifications of the ionic composition of the mucosal fluid were the same in the presence and absence of galactose.7. Sodium and potassium diffusion potentials largely determine both the mucosal and serosal membrane potentials. For the mucosal membrane, PK: PNa is 1-26: 1, and is probably higher for the serosal membrane.Chloride makes no significant contribution to membrane potentials.8. Potentials generated by the electrogenic sodium pump are superimposed on diffusion potentials across the serosal membrane. 218 R.

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Section: Discussioncontrasting

confidence: 63%

Ionic basis of membrane potentials of epithelial cells in rat small intestine

Barry¹,

Eggenton²

1972

The Journal of Physiology

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“…Although this type of kinetic relationship is most characteristic of absorption by passive diffusion, the calcium unidirectional flux ratios with a 1-mM luminal calcium concentration (Table II) (26). Potential difference was calculated from the concentration of potassium in plasma and fluid from the distal end of the test segment, using the Nernst equation (29,30). Negative sign preceding potential difference means the lumen is negative with respect to blood; positive sign means the lumen is positive with respect to blood.…”

Section: Discussionmentioning

confidence: 99%

“…The test solutions contained 50 mM NaCl, 5 mM KCI, 0.5% polyethylene glycol ( (26). Potential difference between blood and intestinal lumen was estimated from the concentrations of potassium (which equilibrates passively across gut mucosa in accord with electrochemical gradients [27][28][29] ) in serum and in fluid aspirated from the distal end of the intestinal segment, using the Nernst equation as previously described (30,31). The unidirectional calcium flux ratios which would be expected if calcium movement was determined entirely by electrochemical gradients were calculated by the Ussing equation (32).…”

mentioning

confidence: 99%

Jejunal and ileal absorption in patients with chronic renal disease. Effect of 1alpha-hydroxycholecalciferol.

Vergne-Marini¹,

Parker²,

Pak³

et al. 1976

J. Clin. Invest.

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“…Unfortunately, that conclusion cannot be derived from the experimental observations since steady-state conditions were not present in the study. Other studies designed to study the mechanism of K secretion in vivo included similar technical limitations (14,15).…”

Section: Resultsmentioning

confidence: 99%