Related Experiment Video
Updated: Aug 15, 2026

Patch Clamp and Perfusion Techniques for Studying Ion Channels Expressed in Xenopus oocytes
Published on: January 10, 2011
Properties of single potassium-selective ionic channels from the apical membrane of rabbit corneal endothelium
Abstract:
The corneal endothelium from several species contains a highly conductive, flickery potassium selective channel in the apical membrane. The channel flicker is not due to blockade. The single channel has an inwardly rectifying current-voltage relationship under symmetrical ionic conditions. Based on reversal potential measurements, it is more than 40:1 selective for potassium over sodium. It also shows subconductance levels. In bathing solutions lacking chloride and bicarbonate, its open probability is less than 0.1 and is quite independent of voltage in the physiological voltage range. Bicarbonate in the bath or DIDs in the pipette increase channel activity. The channel is blocked by external cesium in the 0.5 to 5 mM range. The steepness of the voltage dependence of this blockade is consistent with multiple occupancy.
Related Concept Videos
Primary Active Transport
Non-gated Ion Channels
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
The Role of Ion Channels in Neuronal Computation
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.
Voltage-gated Ion Channels
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Non-gated Ion Channels
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
Voltage-gated Ion Channels
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...

