competition for binding was stereoselective for ( - ) isomers of propranolol , and beta-adrenergic agonists displayed competition for the placental receptor in the order ( - ) isoproterenol greater than ( - ) epinephrine greater than ( - ) norepinephrine , typical of a beta 2 type receptor .
C0014563
epinephrine
C0028351
norepinephrine