STABILIZATION OF SPIDER CRAB NERVE MEMBRANES BY ALKALINE EARTHS, AS MANIFESTED IN RESTING POTENTIAL MEASUREMENTS.
1Marine Biological Laboratory, Woods Hole, Massachusetts, and the Department of Physiology, College of Physicians and Surgeons, Columbia University, New York.
The Journal of General Physiology
|October 30, 2009
Summary
Alkaline earth ions like barium and strontium can prevent potassium and veratrine sulfate from depressing nerve resting potential. These ions also counteract other organic agents that lower nerve potential and excitability.
Area of Science:
- Neuroscience
- Biophysics
- Cellular Physiology
Background:
- The resting potential of non-medullated nerve is crucial for neuronal function.
- Understanding the ionic and molecular mechanisms influencing resting potential is key to comprehending nerve excitability.
Purpose of the Study:
- To investigate the effects of alkaline earth ions (Ba, Sr, Ca, Mg) on the resting potential of spider crab nerve.
- To determine the role of alkaline earths in modulating the effects of potassium and organic agents on nerve potential and excitability.
Main Methods:
- Exposure of non-medullated spider crab nerve to isotonic chloride solutions of alkaline earth ions.
- Application of potassium and various organic agents (veratrine sulfate, saponin, amyl urethane, chloral hydrate, Na salicylate) to assess their effects on resting potential.
- Evaluation of nerve excitability under different ionic and chemical conditions.
Main Results:
- Alkaline earth ions generally do not affect resting potential but can prevent depression by potassium (Ba > Sr > Ca).
- Alkaline earths (Ba > Sr > Ca > Mg) oppose depression by veratrine sulfate, with a linear relationship between veratrine concentration and potential drop.
- Barium neutralizes the depressant effects of other organic agents; alkaline earths reversibly depress excitability.
Conclusions:
- Alkaline earth ions play a significant role in stabilizing nerve resting potential against certain depressant agents.
- The findings provide insights into the mechanisms underlying resting potential and nerve excitability, potentially informing theories on these phenomena.
Related Concept Videos
Resting Membrane Potential
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.
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Resting Membrane Potential
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...
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The Resting Membrane Potential
Overview
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...
At rest, the K+ is the main ion that moves across the membrane through...
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...
At rest, the K+ is the main ion that moves across the membrane through...


