in 2 to 5 day-old hearts there was no inotropic response to adrenaline and the very small maximal response in ventricles rose 5 to 7 fold by 20 days.6 propranolol sensitivity increased slightly ( 2 to 4 times ) with age in all tissue from a pa ( 2 ) value of 7.5 at 2 days to 8.2 at 20 days.7 control cyclic amp was higher in 2 day than in 20 day-old tissue and in atria than ventricular strips or hearts .
C0018827
ventricular
C0018787
hearts