Effect of Galactose on Intracellular Potential and Sodium Activity in Urodele Small Intestine. Evidence for Basolateral Electrogenic Transport

White, J. F.; Imon, Michael

doi:10.1007/978-3-642-69109-6_22

Cited by 5 publications

(2 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Local currents flowing in the epithelium are also said to affect membrane potentials (Schultz, 1972). Evidence has been reported previously that the membrane potential of mature enterocytes can be accounted for by a rheogenic Na+-K+ pump (Okada, Irimajiri, Tsuchiya & Inouye, 1978;Tsuchiya & Okada, 1982), a basolateral K+ conductance and an Na+ and K+ conductance in the brush border membrane (for a review see White & Imon, 1983); K+ channels also seem to be Ca2+-dependent in this tissue (Brown, Burton & Sepulveda, 1983;Tsuchiya & Okada, 1982). More Na--K+-activated ATPase activity has been found in the villus compared with crypt cells (Charney, Gots & Giannella, 1974), though this has not been confirmed using cells homogenized in the absence ofNa+ deoxycholate (Gratecos, Knibiehler, Benoit & Semeriva, 1978).…”

Section: Discussionmentioning

confidence: 99%

“…The situation in the intestine could be further complicated, however, by the possible presence of high concentrations ofextracellular Na+ and K+ in the immediate vicinity ofthe brush border membrane (Alvarado & Lherminier, 1982;Robinson, Van Melle & Johansen, 1983;Lucas & Cannon, 1983;White & Imon, 1983). These anomalous concentrations of Na+ and K+, present in an unstirred layer whose thickness depends on the state of enterocyte development, could affect membrane potential without necessarily changing the concentration of intracellular cations.…”

Section: Cremaschi and Othersmentioning

confidence: 99%

See 1 more Smart Citation

Developmental changes in intra‐enterocyte cation activities in hamster terminal ileum.

Cremaschi¹,

James²,

Meyer³

et al. 1984

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. Intracellular Na+ and K+ activities have been determined under visual control in enterocytes located at known positions along hamster ileal villi in vitro.2. The intracellular K+ activity found in enterocytes migrating over the basal third of villi was significantly less than that found in older enterocytes (83 and 113 mM respectively). The intracellular Na+ activity remained unaffected by the state of enterocyte development (32 mm throughout).3. Extracellular K+ and Na+ activities measured close to the luminal surface of the intestine were always similar to those measured in the bulk of the bathing medium. There was, however, a small difference in K+ activity detected between the bulk solution and solution near the luminal surface of enterocytes (3-4 and 3-63-7 mm respectively). Na+ activity in the villus core was also similar to that of the bathing medium.4. The brush border membrane content of sucrase-isomaltase, determined cytochemically, was found to increase rapidly as enterocytes migrated over the basal third of the villus and to plateau at a point roughly equivalent to that where intracellular K+ activities became maximal.5. The numerous ways by which enterocytes might control their intracellular K+ concentrations during development are emphasized. Attention is nevertheless drawn to the close correspondence seen between different aspects of brush border membrane development and the ability of enterocytes to maintain high internal concentrations of K+.

show abstract