the catechol neurotransmitters competed for [ ( 3 ) h ] dihydroergocryptine binding in the potencies order epinephrine > ( - ) -norepinephrine > dopamine , indicating that [ ( 3 ) h ] dihydroergocryptine ( in the presence of 5 nm spiperone ) was revealing alpha receptors .
C0014563
epinephrine
C0028351
norepinephrine