other adrenergic agonists capable of activating alpha-2 adrenoceptors ( e.g. , epinephrine , norepinephrine and xylazine ) also significantly depressed 3h-ne secretion , whereas selective alpha-1 adrenergic or beta adrenergic agonists were without effect .
C0014563
epinephrine
C0028351
norepinephrine