the antinociceptive properties of intrathecally ( i.t . ) administered [ d-ala2 , n-methyl-phe4 , gly5-ol ] enkephalin ( dampgo ) and [ d-pen2 , d-pen5 ] enkephalin ( dpdpe ) , selective opioid agonists for mu ( mu ) and delta ( delta ) sites , respectively , were compared in rats .
C0014298
enkephalin
C0525856
dpdpe