in comparison with the mu-opioid-receptor agonist , [ d-ala2 , mephe4 , gly-ol5 ] enkephalin and the kappa-opioid-receptor agonist dynorphin a ( 1-13 ) , lower doses of methionine enkephalin [ ( met ] enkephalin ) markedly inhibited the excitation caused by stimulation of the vagal efferent and afferent fibres .
C0014298
enkephalin
C0014295
met ] enkephalin