What question did this study set out to answer?

To measure alternating current impedance changes across the membrane of the squid giant axon during the passage of an active nerve impulse.

May 20, 1939The Journal of General PhysiologyOpen Access

Electric Impedance of the Squid Giant Axon During Activity

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Authors

KCKenneth S. ColeTufts University HCHoward J. CurtisKing's College Hospital NHS Foundation Trust

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Implication

Electrophysiological study demonstrates a dramatic drop in membrane resistance during nerve impulse propagation in squid giant axons, highlighting the mechanism of action potentials.

Key Points

To measure alternating current impedance changes across the membrane of the squid giant axon during the passage of an active nerve impulse.
Measured transverse alternating current impedance across the giant axon of Loligo pealii using narrow paired electrodes across a wide frequency range.
Detected bridge unbalance and voltage deflection during resting and stimulated states using a Wheatstone bridge connected to an amplifier and cathode ray oscillograph.
Membrane phase angle remained unchanged and membrane capacity decreased by approximately 2%, while membrane resistance/conductance dropped from a resting value of 1000 ohm·cm² to an average of 25 ohm·cm².
The onset of resistance change coincided closely with the inflection point on the rising phase of the action potential where membrane current reverses direction.

Cite This Study

Cole et al. (1939) studied this question.

synapsesocial.com/papers/6a0f084eb7cc3b883f22ff33 https://doi.org/10.1085/jgp.22.5.649

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Implication

Electrophysiological study demonstrates a dramatic drop in membrane resistance during nerve impulse propagation in squid giant axons, highlighting the mechanism of action potentials.

Electric Impedance of the Squid Giant Axon During Activity

Discussion

Member takes

Implication

Key Points

Cite This Study

Electric Impedance of the Squid Giant Axon During Activity

Discussion

Member takes

Implication

Key Points

Cite This Study

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