Membrane potential generated by ion adsorption.
Hirohisa Tamagawa1, Sachi Morita2
1Department of Human and Information Systems, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan. tmgwhrhs@gifu-u.ac.jp.
Membranes
|June 25, 2014
Summary
A new adsorption theory challenges the Goldman-Hodgkin-Katz equation for membrane potential. It suggests ion adsorption, not permeability, primarily generates potential across membranes, even impermeable ones.
Area of Science:
- Electrochemistry
- Biophysics
- Physical Chemistry
Background:
- The Goldman-Hodgkin-Katz (GHK) equation is widely accepted for explaining membrane potential.
- The GHK equation considers ion permeability across membranes separating electrolytic solutions.
- Observed potentials across impermeable membranes challenge the GHK equation's universality.
Purpose of the Study:
- To propose an alternative theory for membrane potential generation.
- To investigate the role of ion adsorption versus ion passage.
- To re-evaluate the fundamental understanding of membrane potential origins.
Main Methods:
- Development of an alternative adsorption theory for membrane potential.
- Computational modeling of potential behavior based on the adsorption theory.
- Comparison of theoretical predictions with experimental observations.
Main Results:
- The adsorption theory explains potential generation due to ion adsorption on membrane surfaces.
- Computational results align well with experimental data for both permeable and impermeable membranes.
- The theory provides a viable explanation for nonzero potentials across impermeable membranes.
Conclusions:
- Ion adsorption on membrane surfaces may be the primary driver of membrane potential.
- The established Goldman-Hodgkin-Katz equation may not fully explain all membrane potential phenomena.
- Reconsideration of the fundamental origins of membrane potential is warranted.
Related Concept Videos
01:26What is an Electrochemical Gradient?
118.4K
Adenosine triphosphate, or ATP, is considered the primary energy source in cells. However, energy can also be stored in the electrochemical gradient of an ion across the plasma membrane, which is determined by two factors: its chemical and electrical gradients.
The chemical gradient relies on differences in the abundance of a substance on the outside versus the inside of a cell and flows from areas of high to low ion concentration. In contrast, the electrical gradient revolves around an...
The chemical gradient relies on differences in the abundance of a substance on the outside versus the inside of a cell and flows from areas of high to low ion concentration. In contrast, the electrical gradient revolves around an...
118.4K
01:21The Resting Membrane Potential
117.4K
Overview
117.4K
01:15Resting Potential Decay
5.2K
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...
At rest, the K+ is the main ion that moves across the membrane...
5.2K
01:15Resting Potential Decay
2.3K
2.3K
01:24Resting Membrane Potential
18.3K
The relative difference in electrical charge, or voltage, between the inside and the outside of a cell membrane, is called the membrane potential. It is generated by differences in permeability of the membrane to various ions and the concentrations of these ions across the membrane.
The Inside of a Neuron is More Negative
The membrane potential of a cell can be measured by inserting a microelectrode into a cell and comparing the charge to a reference electrode in the extracellular fluid. The...
The Inside of a Neuron is More Negative
The membrane potential of a cell can be measured by inserting a microelectrode into a cell and comparing the charge to a reference electrode in the extracellular fluid. The...
18.3K
01:24Resting Membrane Potential
8.9K
8.9K