the comparative binding characteristics of the mu opioid receptor selective ligand [ 3h ] - [ d-ala2-mephe4-glyol5 ] enkephalin [ ( 3h ] -dago ) and of the delta receptor ligand [ 3h ] - [ d-pen2 , d-pen5 ] enkephalin [ ( 3h ] -dpdpe ) have been studied in homogenates of both whole brain and of pons/medulla regions from the rat .
C0014298
enkephalin
C0525856
dpdpe