comparison of the relative potencies of pirbuterol , salbutamol and isoproterenol as relaxants of isolated guinea-pig tracheal muscle and as positive chronotropic agents in isolated guinea-pig atria indicate that the relative selectivity of pirbuterol for pulmonary as opposed to cardiac tissue is 9 times greater than that for salbutamol and some 1500 times greater than that for isoproterenol .
C1372804
positive chronotropic
C0022245
isoproterenol