1. The degree of tubular potassium depletion and the decrease of potassium conductance due to hyperpolarizing pulses in striated muscular fibres have been examined with the three micro-electrode voltage-clamp technique. 2. The conductance of the fibre membrane has been measured in different extracellular K+ concentrations from 1 to 10 mM. 3. Comparison of the two sets of measurements shows that changes in tubular K+ concentration are not sufficient to account for the conductance decrease associated with hyperpolarization. 4. The presence of a voltage-dependent gate in series with the inwardly rectifying channel for K+ ions, suggested by Almers (1972a, b), is thus confirmed.
A voltage-dependent gate in series with the inwardly rectifying potassium channel in frog striated muscle.
PERES, ANTONIO
1979-01-01
Abstract
1. The degree of tubular potassium depletion and the decrease of potassium conductance due to hyperpolarizing pulses in striated muscular fibres have been examined with the three micro-electrode voltage-clamp technique. 2. The conductance of the fibre membrane has been measured in different extracellular K+ concentrations from 1 to 10 mM. 3. Comparison of the two sets of measurements shows that changes in tubular K+ concentration are not sufficient to account for the conductance decrease associated with hyperpolarization. 4. The presence of a voltage-dependent gate in series with the inwardly rectifying channel for K+ ions, suggested by Almers (1972a, b), is thus confirmed.
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