further evidence for two discrete populations of alpha-adrenoceptors is provided by , ( a ) the potent but non-competitive effect of prazosin against ( - ) -noradrenaline , ( b ) the presence of a component of the contractions elicited by na and phenylephrine which is resistant to the selective alpha 2-adrenoceptor antagonists rauwolscine and ch-38083 : these responses were inhibited by the selective alpha 1-adrenoceptor antagonists prazosin and ym-12617 , but not by the selective alpha 2-adrenoceptor antagonist bdf-6143 and , ( c ) the relative potency of the yohimbine diastereoisomers rauwolscine and corynanthine against na , phenylephrine and uk-14304 .
C0034784
alpha-adrenoceptors
C0001639
alpha 2-adrenoceptor