agonists displayed a rank order of potency in radioligand binding assays of para-aminoclonidine greater than or equal to uk-14304 greater than ( - ) -epinephrine greater than ( - ) -norepinephrine greater than ( - ) -isoproterenol , consistent with the identification of this protein as an alpha 2-receptor .
C0014563
epinephrine
C0028351
norepinephrine