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Squid Giant Synapse - DISSECTION - Page 2
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The next step will be to desheath the ganglion, i.e. to remove the protective sheath, or skin, that separates the ganglion from sea water. During this step, the presynpatic bundle is dissected "through" the side of hepatopancreas wall which still separates it from the stellate ganglion and the post-synaptic fibres.
View of stellate ganglion and pre- & post-synaptic axons

A view from where the hepatopancreas was located . Beneath (i.e. on the bottom side of the opened up muscle) can be seen the stellate ganglia on either side of the animal (purple arrows) with radiating post-synpatic axons. The presynaptic axon bundle that was tied off is, in this photo, on Top of the muscle.

Note that the axon bundle that was tied off goes through the muscle that encloses the hepatopancreas - i.e. the axon bundle is on the other side of the hepatopancreas muscle from the stellate ganglion.


Desheathing the ganglion
Click HERE for 1.5 min video (13.4 MB)

A thin layer of skin has been almost completely removed. The movie is crucial for illustrating earlier steps in the preparation.

Making a cut under the presynaptic axon bundle.

In the second photo the ganglion is colored in yellow.

cutting away from the inside of the hepatopancreas muscle.

In the second photo the presynaptic axon bundle is colored pink. Because the preparation is basically clear, and the photos are in black and white, here the video is especially useful in visualizing what is going on.

Presynaptic axons (colored pink in the second photo) are freed from the muscle.
Cutting all the unneeded post-synaptic axon bundles, while carefully avoiding the bundle with the very biggest axon (colored in blue). The giant post-synpatic axon is gently freed from connective tissue and from the mantle muscle and finally tied off.
Tying off the postsynaptic axons about 1 cm away from the ganglion.


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