Related Experiment Video
Updated: Aug 4, 2026
10:19
Patch Clamp and Perfusion Techniques for Studying Ion Channels Expressed in Xenopus oocytes
Published on: January 10, 2011
Single potassium channels in corneal epithelium
Investigative Ophthalmology & Visual Science
|September 1, 1990
Summary
Researchers identified a novel, highly conductive ionic channel in corneal epithelia. This stretch-activated channel exhibits unique properties, enabling measurements of cell input resistance and capacitance.
Area of Science:
- Biophysics
- Cell Biology
- Ophthalmology
Background:
- The corneal epithelium plays a crucial role in maintaining ocular surface integrity.
- Ionic channels are fundamental to cellular function, regulating ion transport across membranes.
Purpose of the Study:
- To characterize a frequently occurring ionic channel in the basal cell layers of rabbit and human corneal epithelia.
- To investigate the biophysical properties and potential applications of this novel channel.
Main Methods:
- Utilized patch voltage clamp techniques on cell-attached and excised membrane patches.
- Analyzed unitary currents, conductance, ion selectivity, and open probability under varying conditions (suction, ion concentrations, voltage).
Main Results:
- Identified a highly conductive (165 pS) and K+-selective (PK/PNa > 40:1) ionic channel.
- Demonstrated stretch activation, though with lower sensitivity compared to other known channels.
- Observed current saturation with increasing K+ concentration and block by Cs+, Ba+2, and Ca+2.
Conclusions:
- The novel corneal epithelial channel possesses unique properties, including large conductance and stretch activation.
- Its characteristics suggest potential utility in measuring single-cell input resistance and capacitance.
- Further research may elucidate its specific physiological role in corneal function.
Related Concept Videos
01:24Non-gated Ion Channels
Ion channels are specialized proteins on the plasma membrane that allow charged ions to pass down their electrochemical gradient. Their main function is to maintain the membrane potential which is critical for cell viability. These channels are either gated or non-gated and can transport more than a thousand ions within milliseconds for the cellular event to occur.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
01:19The Role of Ion Channels in Neuronal Computation
A postsynaptic neuron usually receives numerous impulses from several other presynaptic neurons. The axon hillock of the postsynaptic neuron integrates all these signals and determines the likelihood of firing an action potential.
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.
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.
01:26Voltage-gated Ion Channels
Voltage-gated ion channels are transmembrane proteins that open and close in response to changes in the membrane potential. They are present on the membranes of all electrically excitable cells such as neurons, heart, and muscle cells.
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...
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...
01:12Mechanically-gated Ion Channels
Mechanically-gated ion channels are proteins found in eukaryotic and prokaryotic cell membranes that open in response to mechanical stress. Tension, compression, swelling, and shear stress can alter the conformation of the protein, opening a transmembrane channel that allows the passage of ions for signal transmission. In eukaryotes, mechanically-gated channels are distributed in several regions like the neurons, lungs, skin, bladder, and heart, where they play critical roles in numerous...
01:24Non-gated Ion Channels
Ion channels are specialized proteins on the plasma membrane that allow charged ions to pass down their electrochemical gradient. Their main function is to maintain the membrane potential which is critical for cell viability. These channels are either gated or non-gated and can transport more than a thousand ions within milliseconds for the cellular event to occur.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
01:26Voltage-gated Ion Channels
Voltage-gated ion channels are transmembrane proteins that open and close in response to changes in the membrane potential. They are present on the membranes of all electrically excitable cells such as neurons, heart, and muscle cells.
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...
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...