adrenergic agonists compete for [ 3h ] dihydroergocryptine binding sites stereo-selectively ( [ - ] -norepinephrine is 100 times as potent as [ + ] -norepinephrine ) and in a manner compatible with alpha-adrenergic potencies ( epinephrine approximately equal to norepinephrine much greater than isoproterenol ) .
C0014563
epinephrine
C0028351
norepinephrine