Effects of L-valyl-valine anhydride on the blood-perfused canine sinoatrial node and papillary muscle

Experiments were conducted on the canine sinoatrial node and the papillary muscle preparation perfused with the arterial blood from the donor dog through the cannulated sinus node artery and the anterior septal artery.L-valyl-valine anhydride 0.3,1,3,10 microg ia decreased sinus rate 0.2+/-2,10+/-6,21+/-12 beats/min,the artial muscle contractile force 4+/-5,16+/-20,33+/-8,49+/-9% and papillary muscle contractile force 9+/-4, 12+/-4,17+/-10,32+/-25%, respectively. The coronary blood flow did not change significantly. These antagonistic effects on isoproterenol are similar to those on propranolol.
Keywords：L-valyl-valine anhydride; propranolol;isoproterenol;sinoatrial node; papillary muscle; myocardial contraction;heart rate