Prepare the isolated frog heart medical students research in china
By Live Dr - Sun Jan 11, 9:04 am
1. Prepare the isolated frog heart.
Destroy the brain and spinal cord of the toad.
Fix the toad on the frog board.
Cut the skin and chest bone to expose the heart.
Clamp the pericardium with a small forceps then open the pericardium. Identify the different part of the heart. (aorta sinistra, aorta dextra, arterial cone, venous sinus, cardiac atrium, cardiac ventricle, caval vein)
Ligate the aorta dextra.
Put a thread under the aorta sinistra and aorta dextra, turn the heart on the counter part and ligate the caval vein, pay more attention that does not ligate the venous sinus.
Put two threads under the aorta sinistra, one tie a loose knot and put on the proximal part to standby. Another one was used to ligate the aorta sinistra.
Raise the ligation thread on the aorta sinistra, cut a small hole on the aorta sinistra. Insert the straub canula into the arterial cone from the hole and then move the canula toward the ventricle direction and insert it into the cardiac ventricle in the contraction phase. Wash the heart with Ringer’s solution immediately to avoid the blood coagulation
Ligate the standby thread and fix it on the hook of canula. Remove all the tissues and isolate the heart.
2. Wash the heart with Ringer’s solution to avoid the blood coagulation induced block of the canula until the heart looks in white.
3. Clip the heart in relaxation phase by frog heart clip and connect it with tension transduser.
4. Start BL-420 systems, Choose Items, record the contraction curve.
1) Normal contraction curve
2) Change the Ringer’s solution with 0.65% NaCl
3) 2% CaCL2 1-2 drop
4) 2% KCL 1-2 drop
5) 1/10000 norepinephrine
6) 1/100000 acetylcholine
7) 2.5% sodium bicarbonate
8) 3% lactic acid, then 2.5% sodium bicarbonate
1. Keep the fluid in the same leave in straub canula.
2. Before testing a new drug, washing with Ringer’s solution and waiting the heart recovery to the normal level.