without precontraction none of the adrenergic agents had significant effects , but after cholinergic precontraction of the muscles a further contraction could be obtained with the non-selective agonists epinephrine , norepinephrine and isoproterenol , with the alpha 2-agonist b-ht 920 , and with the beta 2-agonist terbutaline .
C0014563
epinephrine
C0028351
norepinephrine