however , after removal of spare postsynaptic vascular alpha 1-adrenoceptors by treatment with the irreversible alpha-adrenoceptor antagonist phenoxybenzamine ( 5 x 10 ( -8 ) m , 1 x 10 ( -7 ) m ) , the alpha 1-adrenoceptor-mediated vasoconstrictor responses of phenylephrine became highly sensitive to antagonism by 8-bromo cgmp and nitroglycerin .
C0034784
alpha-adrenoceptor
C0001638
alpha 1-adrenoceptor