the concentration of phentolamine and prazosin required to inhibit contractions caused by electrical stimulation were about 5 -- 7 times higher than those required to inhibit contractions caused by exogenous adrenaline or noradrenaline , whereas propranolol was equipotent in reducing beta-responses to adrenaline released by electrical stimulation and to exogenous adrenaline .
C0028351
noradrenaline
C0014563
adrenaline