125i-endothelin was displaced by unlabelled endothelin with a inhibition constant ( ki ) of 0.2 nm , whereas an absence of competition was observed with 1 microm of vasoactive substances such as angiotensin ii , arg-vasopressin , atrial natriuretic factor , histamine , epinephrine and norepinephrine , and with the calcium entry blocks nifedipine , diltiazem and d 600 .
C0014563
epinephrine
C0028351
norepinephrine