Squid Giant Axon
Squid Giant Axon - Related Videos
08:58
Colonization of Euprymna scolopes Squid by Vibrio fischeri
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Cited by 28 •
2012
The method outlines the procedure by which the Hawaiian bobtail squid, Euprymna scolopes and its bacterial symbiont, Vibrio fischeri, are raised separately and then introduced to allow for specific colonization of the squid light organ by the bacteria. Colonization detection by bacterially-derived luminescence and by direct colony counting are described.
05:29
Obtaining Hemocytes from the Hawaiian Bobtail Squid Euprymna scolopes and Observing their Adherence to Symbiotic and Non-Symbiotic Bacteria
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Cited by 15 •
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This video will demonstrate how to obtain hemocytes (blood cells) from the Hawaiian bobtail squid, Euprymna scolopes for use in cell biological and bacterial adhesion assays. Hemocytes will be stained with a fluorescent dye and exposed to GFP-labeled bacteria.
11:03
A Method for Extracting Pigments from Squid Doryteuthis pealeii
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Cited by 5 •
2016
A protocol for the extraction of pigments from the nanostructured granules in squid Doryteuthis pealeii chromatophores is presented.
11:12
Whole Mount Preparation of the Adult Drosophila Ventral Nerve Cord for Giant Fiber Dye Injection
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Cited by 21 •
2011
An in vivo dissection of the adult Drosophila ventral nerve cord (VNC) is demonstrated. This particular dissection method causes little damage to the VNC allowing the subsequent labeling of the giant fiber neurons with fluorescent dye for high resolution imaging.
12:53
Electrophysiological Recordings from the Giant Fiber Pathway of D. melanogaster
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Cited by 17 •
2011
The Giant Fiber System is a simple neuronal circuit of adult Drosophila melanogaster containing the largest neurons in the fly. We describe the protocol for monitoring synaptic transmission through this pathway by recording post synaptic potentials in dorsal longitudinal (DLM) and tergotrochanteral (TTM) muscles following direct stimulation of the Giant Fiber interneurons.
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Its unusually wide diameter permits electrodes to be inserted directly into the nerve fiber. This access allows researchers to measure membrane voltage inside the axon while electrical signaling occurs. The resulting measurements connect changes in voltage with the opening and closing of ion channels, making cellular excitability experimentally observable rather than inferred indirectly.
During an action potential, voltage-gated sodium channels open and produce rapid depolarization, meaning the membrane voltage shifts toward a less negative state. Potassium channels then contribute to repolarization, which returns the voltage toward its prior condition. This ordered change in ion conductance explains how the axon generates a brief electrical signal.
Experiments with this preparation showed that membrane voltage changes reflect regulated changes in ion conductance. That relationship provided a mechanistic basis for understanding neuronal excitability and action-potential propagation. It also supplied essential experimental principles for the Hodgkin-Huxley model, which describes how changing sodium and potassium conductances shape electrical signaling.
Researchers insert electrodes directly into the unusually large nerve fiber and monitor its membrane voltage during electrical activity. They then relate the recorded voltage changes to the sequential behavior of voltage-gated sodium and potassium channels. This approach provides a direct electrophysiological workflow for examining excitability and the propagation of action potentials.
Recordings can show how membrane voltage changes as ion channels open and close during an action potential. They therefore help investigators examine rapid depolarization, subsequent repolarization, ion conductance, and signal propagation. These outcomes connect measurable electrical events at the membrane with the cellular processes responsible for transmitting neural information.
The preparation continues to support electrophysiology, the study of electrical activity in nerve cells, as well as research on neural signaling. Its experimental importance comes from linking direct membrane-voltage measurements to cellular excitability and information transmission. It also provides scientific context for the principles underlying the Hodgkin-Huxley model and action-potential propagation.