This study investigates the effects of vasopressin 1A receptor blockers on brain edema in a mouse model. The methodology involves surgical procedures to administer the blocker and monitor its effects on water influx in brain tissue.
Begin with an anesthetized mouse with a pre-implanted cannula. The exposed left jugular vein is connected to the heart through a primary vein.
The mouse’s middle cerebral artery was transiently occluded.
This increased arginine-vasopressin in the brain, which binds to vasopressin 1A receptors on the blood vessels and causes water influx into brain tissue, resulting in edema.
Ligate the jugular vein at two points. Make an incision between them, insert the catheter through the incision toward the heart, and secure it.
Close the skin incision.
Secure the catheter to the mouse’s back and connect it to a micro-infusion pump.
Apply an analgesic to prevent post-operative pain. Allow the mouse to awaken.
Administer a vasopressin 1A receptor blocker into the jugular vein.
This allows blocker molecules to circulate through the heart, reach the brain vessels, and enter the brain tissue.
The blockers bind to vasopressin 1A receptors, prevent water influx, and reduce brain edema.
Immediately after removing the common carotid artery suture, disinfect the back of the neck with a 10% povidone iodine scrub solution, and use a size 10 surgical scalpel blade to make a 1 centimeter incision. Then re-sterilize the front of the neck and reopen the surgical wound. Now, tunnel a piece of 0.94 millimeter outer diameter tubing nested within a piece of 3.18 millimeter outer diameter tubing under the skin of the animal from the back to the front of the neck, and exteriorize the tubing when it reaches the front incision.
Remove the subcutaneous adipose tissue from the left side of the front of the neck, about one centimeter laterally from the midline. Then locate the left jugular vein under the dissecting microscope, and place two ties along the vein 5 millimeters apart, slightly stretching the vessel. Next, use microvascular scissors to make a small hole on the jugular vein between the two ties, and insert the tip of the inner tubing 5 millimeters deep, caudally toward the heart.
Secure the tubing with both ties to the jugular vein, and use 3-0 silk suture to close the skin on the front of the neck. Then secure the tubing to the skin on the back of the neck with the suture, and connect the tubing to a micro-infusion intravenous pump through a swivel. Infiltrate the skin incisions on the front and the back of the neck with 0.2 milliliters of 0.5% Bupivacaine to prevent postoperative pain and allow the animal to awaken in the recovery chamber with monitoring.
When the animal is recumbent, set the infusion rate for a continuous 48-hour intravenous treatment of Conivaptan or vehicle at 1.5 milliliters per kilogram per hour, and start the infusion.
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