PROCEDURE FOR CAUSING INFARCTS AND
STUNNED MYOCARDIUM IN THE RAT
Weigh and anaesthetize rat
Shave, intubate and ventilate
Open chest and expose heart
-For chronic studies:
1. make a craniocaudal incision of about 2cm (100-150g rat) parallel with and slightly to the left of the sternum, cut through both the skin and ribs untill ribs are exposed
2. poke a blunt curved forceps between fifth and sixth ribs about 2mm to left of sternum
3. widen gap to about 15mm with lateral pressure with forceps
4. Cut the sixth rib with fine pointed scissors at about 0.5 cm to left of sternum
5. hold the sternal end of this rib with one forceps and use another to cut the pericardium and exteriorize the heart (light pressure on the thorax will help to bring the heart outside without damage)
Ligate or stun coronary artery
A. Hold the left ventricle between the thumb and index finger of left hand
B. A small curved needle (corneal needle 3/8 circle, 9mm) and black braided nonslipping silk, size 6-0 thread is used
C. Perform one of the following
1. Ligation of left coronary arteryat base of heart:
- insert the needle into the margin of the pulmonary cone and exit through the middle of an imaginary line that connects this horizontally with the insertion line of the left auricular appendage
2. Ligation of the left coronary artery at midline of heart:
- the ligature should be placed along an imaginary line that connects the point of origin of the artery (from above) to the apex of the heart in a similar fashion as that described above.
3. Stunning: (method devised for dog)
-use a silk ligature snare
-previously in the dog during the following procedures the tidal volume and rate were adjusted and NaHCO
-occlude the vessel for 5 minutes then reperfuse for 10 minutes. This was repeated 12 times, but only 3-5 may be necessary.
-finally the heart is reperfused for 90 minutes
Replace heart and close cavity (for a chronic infarct)