propranolol at 3 x 10 ( -7 ) m remarkably inhibited the positive chronotropic effect of da in both euthyroid and hypothyroid rats , and 1 x 10 ( -6 ) m phentolamine inhibited the effects of da in the presence of propranolol in hypothyroid rats .
C1372804
positive chronotropic
C0031448
phentolamine