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| RELATIONSHIP BETWEEN SODIUM-TRANSPORT AND INTRACELLULAR ATP IN ISOLATED PERFUSED RABBIT PROXIMAL CONVOLUTED TUBULE |
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| Author(s): BECK JS, BRETON S, MAIRBAURL H, LAPRADE R, GIEBISCH G |
| Source: AMERICAN JOURNAL OF PHYSIOLOGY Volume: 261 Issue: 4 Pages: F634-F639 Part: Part 2 Published: OCT 1991 |
| Times Cited: 56 References: 45 |
| Abstract: The effect of alterations in sodium transport on cell ATP content and pH in the isolated perfused proximal convoluted tubule (PCT) of the rabbit was examined. Stimulating sodium transport by the addition of luminal glucose and alanine decreased cell ATP from 4.44 +/- 0.93 to 2.69 +/- 0.62 mM (n = 4), increased intracellular pH by 0.13 +/- 0.02 (n = 7), and increased cell volume by 0.10 +/- 0.02 nl/mm (n = 4). Blocking the sodium pump with 10(-4) M strophanthidin in tubules in which sodium transport had been stimulated increased cell ATP from 2.04 +/- 0.24 to 2.42 +/- 0.32 mM (n = 6). In parallel experiments the same dose of strophanthidin depolarized the basolateral membrane from -52.6 +/- 1.9 to -6.4 +/- 1.6 mV, depolarized the transepithelial potential from -3.2 +/- 0.3 to -0.1 +/- 0.1 mV, and reduced the basolateral membrane potassium transference number from 0.47 to 0.26 indicating a reduction in basolateral potassium conductance. Since strophanthidin caused a cell alkalinization of 0.15 +/- 0.03, this latter effect cannot be due to changes of intracellular pH. Strophanthidin caused no change in cell volume over the period studied, suggesting that stretch-activated potassium channels are not involved either. Instead, potassium conductance inhibition may be the result of the closure of ATP-sensitive potassium channels. These same channels might thus be partly responsible for the increase in potassium conductance commonly observed during stimulation of sodium transport. |
| Document Type: Article |
| Language: English |
| Reprint Address: BECK, JS (reprint author), UNIV MONTREAL, MEMBRANE TRANSPORT RES GRP, MONTREAL H3C 3J7, QUEBEC CANADA |
Addresses:
1. YALE UNIV, SCH MED, DEPT CELLULAR & MOLEC PHYSIOL, NEW HAVEN, CT 06510 USA |
| Publisher: AMER PHYSIOLOGICAL SOC, 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 |
| Subject Category: Physiology |
| IDS Number: GK869 |
| ISSN: 0002-9513 |
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