Measuring Brain Glutamate Levels Under Anesthesia in Neonatal Piglets Using a Microelectrode Array
筆記録
To begin, create a 4- to 6-centimeter midline incision along the skull using caution to avoid scoring the skull with the scalpel. Once the incision is made, use gentle retraction and blunt dissection to elevate the scalp from the skull.
Next, gently scrub the skull with a gauze pad to remove any connective tissue and expose the suture lines. Then, determine the intended location for the craniotomy. If the area of interest remains obscured, further reflect the scalp.
Now, use a surgical drill to create a craniotomy window that is about 0.25 square centimeters overlying the structure of interest. Be careful not to injure the dura or the underlying brain. As needed, use fine surgical tools to excise the dura overlying the brain tissue. Use extreme care to avoid damaging the brain.
This experiment utilizes a previously described enzyme-based microelectrode array precoated with glutamate oxidase and electroplated with MPD. The microelectrode arrays have a 40-millimeter rigid shaft customized for use with piglets. Secure the metal arm to the micromanipulator, and then position the microelectrode array as vertically as possible over bregma.
Then, carefully lower the array as low as possible without touching the surface of the skull, noting the coordinates of bregma. Now, use a piglet brain atlas to determine the exact stereotaxic coordinates of the structure of interest. Then, reposition the microelectrode accordingly.
Next, place the pseudo-reference electrode under the scalp, ensuring contact with the animal. Now, slowly lower the microelectrode array into the brain to nearly the appropriate depth. For the final 2 millimeters of travel, use a hydraulic microdrive to gently lower the array into the structure of interest with minimal tissue trauma.
After the microelectrode array is positioned, wait 30 minutes to allow the electrodes to reach baseline. Then, take measurements for about three hours. If the piglet is to survive the experiment, close the incision after collecting data.
