Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Voltage-gated Ion Channels01:26

Voltage-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...
Voltage-gated Ion Channels01:26

Voltage-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...
Resting Potential Decay01:15

Resting Potential Decay

The resting membrane potential of a neuron (-70mV) is sustained due to the selective ion permeability of the membrane. At the resting potential, the membrane is slightly permeable to ions like sodium (Na+) and chloride (Cl−) and highly permeable to potassium ions (K+). Differences in the ions' concentration inside the cell compared to the outside are maintained by membrane transport proteins like channels and pumps.
At rest, the K+ is the main ion that moves across the membrane through...
Ligand-Gated Ion Channel Receptor: Gating Mechanism01:30

Ligand-Gated Ion Channel Receptor: Gating Mechanism

Ligand-gated ion channels are transmembrane proteins that play a vital role in intercellular communication and functions of the nervous system. They allow the influx of ions across the membrane once the neurotransmitter binds, allowing the subsequent transmission of electrical excitation across the neurons. Other ligand-gated ion channels, like the γ-aminobutyric acid (GABA) receptor, permit anions like chloride into the cells on the binding of the GABA molecule. Their entry into the cell...
The Role of Ion Channels in Neuronal Computation01:19

The 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.
Non-gated Ion Channels01:24

Non-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.

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

ENaC processing in rat kidney: effects of salt loading and ADH.

American journal of physiology. Renal physiology·2026
Same author

How does the kidney conserve Na<sup>+</sup> in a salt-scarce environment?

American journal of physiology. Renal physiology·2026
Same author

Processing of ENaC in mouse kidney: effects of aldosterone and a Liddle syndrome mutation.

American journal of physiology. Renal physiology·2026
Same author

Kinetics of aldosterone-dependent ENaC trafficking in the kidney.

The Journal of general physiology·2025
Same author

Optimizing renal transporter immunodetection: consequences of freeze-thaw during sample preparation.

American journal of physiology. Renal physiology·2024
Same author

Control of ENaC ubiquitination.

American journal of physiology. Renal physiology·2024

Related Experiment Video

Updated: May 25, 2026

Whole-cell Patch-clamp Recordings for Electrophysiological Determination of Ion Selectivity in Channelrhodopsins
08:39

Whole-cell Patch-clamp Recordings for Electrophysiological Determination of Ion Selectivity in Channelrhodopsins

Published on: May 22, 2017

Ion selectivity and current saturation in inward-rectifier K+ channels.

Lei Yang1, Johan Edvinsson, Henry Sackin

  • 1Department of Physiology and Biophysics, Weill-Cornell Medical College, New York, NY 10065, USA.

The Journal of General Physiology
|February 1, 2012
PubMed
Summary

The inward-rectifier potassium channel Kir1.1 (ROMK) shows current saturation due to a binding site near its outer mouth. This site influences ion permeation and block, with Mg2+ significantly affecting K+ conductance.

More Related Videos

Recapitulation of an Ion Channel IV Curve Using Frequency Components
10:14

Recapitulation of an Ion Channel IV Curve Using Frequency Components

Published on: February 8, 2011

Measurement of Ion Concentration in the Unstirred Boundary Layer with Open Patch-Clamp Pipette: Implications in Control of Ion Channels by Fluid Flow
05:42

Measurement of Ion Concentration in the Unstirred Boundary Layer with Open Patch-Clamp Pipette: Implications in Control of Ion Channels by Fluid Flow

Published on: January 7, 2019

Related Experiment Videos

Last Updated: May 25, 2026

Whole-cell Patch-clamp Recordings for Electrophysiological Determination of Ion Selectivity in Channelrhodopsins
08:39

Whole-cell Patch-clamp Recordings for Electrophysiological Determination of Ion Selectivity in Channelrhodopsins

Published on: May 22, 2017

Recapitulation of an Ion Channel IV Curve Using Frequency Components
10:14

Recapitulation of an Ion Channel IV Curve Using Frequency Components

Published on: February 8, 2011

Measurement of Ion Concentration in the Unstirred Boundary Layer with Open Patch-Clamp Pipette: Implications in Control of Ion Channels by Fluid Flow
05:42

Measurement of Ion Concentration in the Unstirred Boundary Layer with Open Patch-Clamp Pipette: Implications in Control of Ion Channels by Fluid Flow

Published on: January 7, 2019

Area of Science:

  • Molecular Biology
  • Biophysics
  • Ion Channel Physiology

Background:

  • Inward-rectifier potassium channels, like Kir1.1 (ROMK), are crucial for regulating cell membrane potential.
  • Understanding ion permeation and current saturation mechanisms is key to their physiological function.

Purpose of the Study:

  • To investigate the molecular features of Kir1.1 (ROMK) channels responsible for current saturation.
  • To compare the effects of different permeant ions (K+, Rb+, NH4+) on channel kinetics and identify key binding sites.

Main Methods:

  • Electrophysiological recordings to measure maximal currents (i(max)) and apparent K(m) for K+, Rb+, and NH4+.
  • Mutagenesis of charged residues in the extracellular domain to assess their role in ion block.
  • Kinetic modeling to simulate ion movement and channel block.

Main Results:

  • Current saturation in Kir1.1 (ROMK) is primarily controlled by a binding site near the channel's outer mouth.
  • This site exhibits selectivity for divalent cations like Mg2+ over Ca2+ and prefers K+ over Rb+ and NH4+.
  • Mutating charged residues reduced Mg2+ block, and Mg2+ significantly increased the K(m) for K+ conductance.

Conclusions:

  • A specific binding site at the outer pore entrance governs current saturation in Kir1.1 (ROMK) channels.
  • Ion permeability is more influenced by interactions within the selectivity filter.
  • A five-state kinetic model effectively simulates ion permeation and block features.