pretreatment studies whereby various receptor antagonists ( naloxone , diprenorphine , phentolamine , d-l-propranolol or atropine ) were given iv 5 min before subsequent iv administration of damea , dalea , mea or lea ( 16 nmoles ) showed that naloxone , diprenorphine and atropine blocked the depressor and bradycardic effects of dalea and damea .
C0004259
atropine
C0428977
bradycardic