小中大Dissection of hippocampus and cortex:
Sacrifice the rat by placing a plastic dish containing dry ice in the cage and then pouring water into this plastic dish; cover the top of the cage with a bag.
After the rat fails to move spontaneously or in response to pain (touch the eye and look for a reflex), incise along the abodmen and remove the uterus. Place the pups into the large culture dish.
Remove the heads of the pups and place in a 10cm dish
For each head, remove the skin and cut along the scalp in the midline with fine scissors. Make a similar midline cut in the calvarium. Deflect the calvarium with a blunt spatula and scoop the brain into another 10cm dish containing ice-cold DM/KY.
Dissect the coritces: place the brain ventral side up. Place the spatula in the medial aspect of the ventral cortex and midbrain and cut the cortices off. Discard the midbrain.
Dissect the hippocampus and cortex: place a cortex medial side up and place the spatula into the lateral ventricle pushing forward through the lateral aspect of the frontal cortex. Extend the cut through the cortex inferiorly and superiorly to isolate the posterior half of cortex and hippocampus. Discard the remainder.
Dissect the hippocampus from the cortex: place the spatula in the lateral ventricle underneath the hippocampus. Make cuts superiorly and inferiorly to free the respective ends of the hippocampus. Roll out the hippocampus with the spatula and cut the hippocampus from the cortex near the dendate/entorrhinal cortex junction. Place the individual cortices or hippocampi in 10cm dish containing ice-cold DM/KY.
Add the papain to the enzyme solution before stripping the meninges (or 30min before anticipated completion of dissection) and place the papain and trypsin inhibitor solutions in a 37oC water bath.
Strip the meninges and cut the tissue into small 1mm3 pieces.
Sterile filter the papain and trypsin inhibitor solutions.
Transfer all of the cortical/hippocampal tissue to a 15ml conical tube. Use one 15ml tube per 5 cortices dissected. Once the tissue has settled remove the extra DM/KY solution.
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