Effects of potassium ions and sodium ions on membrane potential of epithelial cells in rat duodenum

Okada, Yasunobu; Sato, Toshiharu; Inouye, Akira

doi:10.1016/0005-2736(75)90062-0

Cited by 42 publications

(28 citation statements)

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“…Assessing the basis of membrane potentials in intestinal tissues cannot, in our opinion, be divorced from a The dissection of the helicoidal colon of the pig is difficult and the tissue is fragile, so that it takes up to 10 min from killing the animal to placing the colon in oxygenated medium. The fact that membrane potentials measured subsequently correspond to the highest values recorded from other in vitro preparations of intestine (Rose & Schultz, 1971;Ellory, Evans, Heal & Smith, 1972;Okada et al 1975) provides some evidence that the tissue survives this treatment. New-born tissues are known to be resistant to anoxia and this might have helped in the present work.…”

Section: Discussionmentioning

confidence: 77%

“…It is probably still correct, however, to assume that Vt represents that portion of Na+ transport which is electrogenic. The absolute value of Vt in pig colon (3-5 mV) is low compared with other mammalian colons, yet the conductance is similar (6.5 and 4-5 mmho cm-2 for the new-born and 10-day-old pig compared with 8X3 and 9 3 mmho cm-2 for human and rat colon used in vitro: Grady, Duhamel & Moore, 1970;Edmonds & Marriott, 1970 (Henin & Cremaschi, 1975;Okada et al 1975). The discrepancy between changes in Vm and Vt was used on those occasions as evidence for the presence of an extracellular high conductance shunt.…”

Section: Discussionmentioning

confidence: 98%

“…It is probably no coincidence that reported values for different tissues tend to increase as investigators become more aware of the problems involved. For adult intestines at least it has been reported that the values of membrane potential obtained are critically dependent on the time of preparation and on whether the tissue has been damaged mechanically during preparation (Okada et al 1975). Recordings of low membrane potentials may be correct, but they could also result from poor stripping of the mucosa or imperfect sealing of micro-electrodes within cells.…”

Section: Discussionmentioning

confidence: 99%

“…Origin of the microvillar membrane potential (Vm) The microvillar membrane potential of mammalian small intestine, measured in the absence of actively transported non-electrolyte, depends on Na+ and K+ (McKenney, 1969;Rose & Schultz, 1971;Ellory et al 1972;Barry & Eggenton, 1972;Okada et al 1975;van Os & Slegers, 1975;Reuss & Finn, 1975), but not on Cl- (Rose & Schultz, 1971;Barry & Eggenton, 1972;Okada et al 1975). Vm for the large intestine shows a Cl-dependence, the effect of other monovalent ions being more debatable.…”

Section: Discussionmentioning

confidence: 99%

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Electrical properties of pig colonic mucosa measured during early post‐natal development.

Hénin¹,

Smith²

1976

The Journal of Physiology

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SUMMARY1. Microvillar membrane (Vm) and transmural (Vt) potential differences were measured in proximal colon taken from pigs at birth and up to 10 days of age.2. Vm remained independent of the age of the animal provided it was measured in the absence of methionine. The over-all mean was -43-3 mV. Adding methionine to fluid bathing the mucosal surface of new-born pig colon caused a 9-8 mV depolarization of Vm and a 6-7 mV increase in Vt. These effects, which were Na+-dependent, were not seen in the 10-day-old animal.3. Substituting S042-for Cl-in methionine-free medium caused a hyperpolarization in Vm. Increasing the concentration of K+ caused corresponding depolarization. Substituting choline for Na+ had no effect on Vm. Cl-and K+ movement across the microvillar membrane together account for the bulk of the measured membrane potential. These results apply to all stages of development.4. Na+ uptake across the microvillar membrane of the new-born pig colon was increased in the presence of methionine. This effect disappeared in older animals. Na+ uptake in the absence of methionine doubled during the first 24 h of post-natal life. This increase was maintained using colons taken from older animals.5. Methionine depolarization of Vm in the new-born pig colon is probably caused by the electrogenic influx of Na+. The ability of the colon to actively concentrate methionine within its mucosa disappears at the same time as methionine ceases to affect Vm and Vt. It is suggested that methionine and Na+ form a ternary complex with a carrier in the brush border of the new-born pig colon and that this carrier is lost or modified during early post-natal development.

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Section: Discussionmentioning

confidence: 77%

Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Electrical properties of pig colonic mucosa measured during early post‐natal development.

Hénin¹,

Smith²

1976

The Journal of Physiology

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“…The enterocyte response to short-term changes in mucosal Na ϩ is well studied (57,59,69). We simulated short-term changes in the concentration of mucosal Na ϩ ([Na m ]) by changing the mucosal Na ϩ from its base value of 140 to 100 mM and back again in a stepwise manner.…”

Section: Short-term Response To Mucosal Na ϩmentioning

confidence: 99%

Transepithelial glucose transport and Na⁺/K⁺ homeostasis in enterocytes: an integrative model

Thorsen

Drengstig

Ruoff

2014

American Journal of Physiology-Cell Physiology

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Thorsen K, Drengstig T, Ruoff P. Transepithelial glucose transport and Na ϩ /K ϩ homeostasis in enterocytes: an integrative model. Am J Physiol Cell Physiol 307: C320 -C337, 2014. First published June 4, 2014; doi:10.1152/ajpcell.00068.2013.-The uptake of glucose and the nutrient coupled transcellular sodium traffic across epithelial cells in the small intestine has been an ongoing topic in physiological research for over half a century. Driving the uptake of nutrients like glucose, enterocytes must have regulatory mechanisms that respond to the considerable changes in the inflow of sodium during absorption. The Na-K-ATPase membrane protein plays a major role in this regulation. We propose the hypothesis that the amount of active Na-K-ATPase in enterocytes is directly regulated by the concentration of intracellular Na ϩ and that this regulation together with a regulation of basolateral K permeability by intracellular ATP gives the enterocyte the ability to maintain ionic Na ϩ /K ϩ homeostasis. To explore these regulatory mechanisms, we present a mathematical model of the sodium coupled uptake of glucose in epithelial enterocytes. Our model integrates knowledge about individual transporter proteins including apical SGLT1, basolateral Na-K-ATPase, and GLUT2, together with diffusion and membrane potentials. The intracellular concentrations of glucose, sodium, potassium, and chloride are modeled by nonlinear differential equations, and molecular flows are calculated based on experimental kinetic data from the literature, including substrate saturation, product inhibition, and modulation by membrane potential. Simulation results of the model without the addition of regulatory mechanisms fit well with published short-term observations, including cell depolarization and increased concentration of intracellular glucose and sodium during increased concentration of luminal glucose/sodium. Adding regulatory mechanisms for regulation of Na-K-ATPase and K permeability to the model show that our hypothesis predicts observed long-term ionic homeostasis.enterocytes; epithelial transport; homeostasis; mathematical modeling; ionic regulation THE UPTAKE AND TRANSPORT OF glucose by the epithelial enterocytes in the small intestine are essential steps in all higher animals. Much of the glucose uptake in the small intestine is coupled to transport of sodium, and the different transporter proteins involved in the sodium coupled glucose uptake are well known (23,61,67,97). Although the electrochemical kinetics of the individual transporter proteins responsible for glucose and nutrient uptake are fairly elucidated (19,54,67,82,97), the combined function in which these transporters drive a net inflow of nutrients from the intestinal lumen to the serosal blood has not yet been modeled in detail.We have developed a mathematical model of an enterocyte that incorporates the available kinetic data from studies on individual transporter proteins. The model includes apical SGLT1 (the glucose sodium cotransporter), coupled apical flow of Na ϩ an...

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Low‐frequency voltage noise in a mammalian bone cell clone

Ferrier

Dixon

Illeman

et al. 1982

Journal Cellular Physiology

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Measurements were made of plasma membrane voltage noise in cells of a bone cell clone. The measurements were made under conditions intended to approximate in vivo conditions more closely than in previous electrical measurements on small mammalian cells. Mononucleate cells of normal size, imbedded in a collagen matrix, were used. The electrical state of the cell membrane under normal conditions was characterized by low-frequency random fluctuations (noise) of high magnitude. Hyperpolarizing spikes were observed in some cells. Power spectrum analysis revealed that the random fluctuations were actually a sum of incoherent spike patterns, with spikes of the same time width as those seen in the clearly spiking patterns. This analysis, combined with similar measurements in a high [K+], low [Na+] medium, showed that the fluctuation/spiking phenomenon resulted from modulation of K+ and Na+ transport by a control process at a level higher than that of the individual channels. This process persisted when the membrane potential was depolarized. These results indicate that the membrane potential is not part of the feedback loop producing the fluctuation/spiking phenomenon.

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Effects of potassium ions and sodium ions on membrane potential of epithelial cells in rat duodenum

Cited by 42 publications

References 30 publications

Electrical properties of pig colonic mucosa measured during early post‐natal development.

Electrical properties of pig colonic mucosa measured during early post‐natal development.

Transepithelial glucose transport and Na⁺/K⁺ homeostasis in enterocytes: an integrative model

Low‐frequency voltage noise in a mammalian bone cell clone

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Effects of potassium ions and sodium ions on membrane potential of epithelial cells in rat duodenum

Cited by 42 publications

References 30 publications

Electrical properties of pig colonic mucosa measured during early post‐natal development.

Electrical properties of pig colonic mucosa measured during early post‐natal development.

Transepithelial glucose transport and Na+/K+ homeostasis in enterocytes: an integrative model

Low‐frequency voltage noise in a mammalian bone cell clone

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Transepithelial glucose transport and Na⁺/K⁺ homeostasis in enterocytes: an integrative model