to investigate adrenergic receptor-mediated responses in dog gastrocnemius-plantaris muscle , several catecholamine agonists , isoproterenol , epinephrine , norepinephrine , and phenylephrine , and two antagonists , propranolol and phenoxybenzamine , were given during repetitive , isotonic , tetanic contractions .
C0007412
catecholamine
C0028351
norepinephrine