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Volume-regulatory potassium release from isolated perfused rat kidney
M Joannidis1, H Völkl, W Pfaller
1Institut für Physiologie der Universität Innsbruck, Osterreich.
Renal Physiology and Biochemistry
|September 1, 1989
Summary
This study shows that barium and verapamil block potassium release from rat kidneys during cell swelling. These blockers impair volume regulatory potassium release and cell volume regulation, suggesting alternative mechanisms may persist.
Area of Science:
- Nephrology
- Cell Physiology
- Ion Transport
Background:
- Cell volume regulation is crucial for kidney function.
- Potassium (K+) release is a key mechanism in cell volume regulation.
- Understanding the role of ion channels in this process is vital.
Purpose of the Study:
- To investigate potassium release in response to hypotonic stress in isolated perfused rat kidneys.
- To determine the effect of potassium channel blocker barium and calcium channel blocker verapamil on this process.
- To explore cell volume regulation in mouse proximal tubules.
Main Methods:
- Isolated perfused rat kidney model.
- Continuous measurement of effluent potassium activity.
- Administration of hypotonic perfusate, barium, and verapamil.
- Perfusion of isolated mouse proximal tubules.
Main Results:
- Hypotonic perfusate induced transient potassium release.
- Barium and verapamil significantly inhibited this potassium release.
- Verapamil partially inhibited cell volume regulation in mouse proximal tubules.
- Both blockers impaired volume regulatory potassium release and cell volume regulation.
Conclusions:
- Effluent potassium activity measurement is effective for studying cellular potassium release.
- Volume regulatory potassium release and cell volume regulation are sensitive to barium and verapamil.
- Persistent cell volume regulation may involve slow potassium release or K+-independent mechanisms.