Abstract |
Effects of warm hypoxia and ischemia on electrophysiologic properties of isolated perfused mouse proximal straight tubules were studied. Oxyrase (5 to 10 microliters/mL) was added to the hypoxic and ischemic solutions to lower the oxygen tension to 5 mm Hg. The ischemic solution also simulated acidosis, K+ and lactate accumulation, and substrate deprivation. Twenty-minute tubular perfusion with the hypoxic and ischemic solutions (lumen and bath) at 37 degrees C did not significantly alter basolateral membrane potential, basolateral K+ transference number, or intracellular Na+ activity from control values of -69 +/- 1 mV (N = 91), 0.71 +/- 0.01 (N = 15), and 15.2 +/- 0.8 mM (N = 12), respectively. However, the hypoxic and ischemic perfusions decreased transepithelial potential by 40% ( hypoxia: -1.7 +/- 0.1 to -1.1 +/- 0.1 mV [ N = 30; P < 0.001]; ischemia: -1.4 +/- 0.1 to -0.82 +/- 0.05 mV [N = 17; P < 0.001]). A similar extent of reduction in transepithelial resistance was observed ( hypoxia: 14.3 +/- 1.0 to 9.2 +/- 1.1 omega.cm2 [N = 7; P < 0.005]; ischemia: 12.6 +/- 1.2 to 8.1 +/- 1.0 omega.cm2 [N = 6; P < 0.03]). In addition, neither apical (R(ap)) nor basolateral (Rbl) cell membrane resistances were significantly altered after the ischemic perfusion (control: R(ap) = 369 +/- 48 omega.cm2; Rbl = 92 +/- 11 omega.cm2 [N = 63]; reperfusion: R(ap) = 454 +/- 88 omega.cm2; Rbl = 101 +/- 16 omega.cm2 [N = 21]). It was concluded that tubular cells are able to maintain their electrogenic ionic transport after short-term exposure to hypoxic or ischemic conditions. However, cell-to-cell junctions are damaged by these insults, which could possibly increase leakage and decrease the efficiency of the active transport.
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Authors | Y You, D J Hirsch, N S Morgunov |
Journal | Journal of the American Society of Nephrology : JASN
(J Am Soc Nephrol)
Vol. 3
Issue 4
Pg. 965-74
(Oct 1992)
ISSN: 1046-6673 [Print] United States |
PMID | 1333293
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Isotonic Solutions
- Ouabain
- Ringer's Solution
- Sodium
- Oxygenases
- Oxyrase
- Sodium-Potassium-Exchanging ATPase
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Topics |
- Animals
- Cell Hypoxia
(drug effects, physiology)
- Intracellular Fluid
(metabolism)
- Ischemia
(physiopathology)
- Isotonic Solutions
(pharmacology)
- Kidney Tubules, Proximal
(blood supply, drug effects, physiopathology)
- Male
- Membrane Potentials
- Mice
- Organ Culture Techniques
- Ouabain
(pharmacology)
- Oxygenases
(pharmacology)
- Reperfusion
- Ringer's Solution
- Sodium
(metabolism)
- Sodium-Potassium-Exchanging ATPase
(antagonists & inhibitors, drug effects)
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