the apparent affinity of naloxone at cerebral and spinal sites was estimated using selective mu [ d-ala2 , gly-o15 ] -enkephalin ( dago ) and delta [ d-pen2 , d-pen5 ] enkephalin ] ( dpdpe ) opioid agonists in the mouse warm water tail-withdrawal test in vivo ;
C0014298
enkephalin
C0525856
dpdpe