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Basolateral membrane potassium channels in rabbit cortical thick ascending limb
A M Hurst1, M Duplain, J Y Lapointe
1Membrane Transport Research Group, Université de Montréal, Quebec, Canada.
The American Journal of Physiology
|August 1, 1992
Summary
Potassium (K) exit across the rabbit cortical thick ascending limb (CTAL) basolateral membrane is facilitated by voltage-sensitive K channels. Mild collagenase treatment enables patch clamp recordings from this membrane.
Area of Science:
- Physiology
- Nephrology
- Membrane Biophysics
Background:
- Potassium (K) transport is crucial for kidney function.
- Understanding K exit mechanisms in the renal tubule is essential for comprehending salt and water balance.
Purpose of the Study:
- To investigate the nature of potassium exit across the basolateral membrane of the rabbit cortical thick ascending limb (CTAL).
- To identify ion channels involved in K transport in the CTAL basolateral membrane.
Main Methods:
- Utilized the patch clamp technique on isolated rabbit CTAL basolateral membrane.
- Employed mild collagenase treatment for membrane exposure.
- Performed cell-attached and excised patch recordings.
Main Results:
- Identified a K-selective, inwardly rectifying channel with specific conductance and reversal potential.
- Demonstrated strong voltage dependence and block by barium, but not calcium.
- Confirmed high K selectivity (K:Na permeability ratio of 100) in excised patches.
Conclusions:
- Established that patch clamp recordings are feasible from the rabbit CTAL basolateral membrane using mild collagenase treatment.
- Concluded that voltage-sensitive K channels mediate, at least in part, K exit across the CTAL basolateral membrane.