Met-Enkephalinamide is a peptide opioid receptor agonist and derivative of Met-enkephalin .1,2 It binds to opioid receptors in rat cerebellum homogenates (IC50 = 0.2 µM) and reduces the twitch height in electrically stimulated isolated guinea pig ileum and isolated mouse vas deferens. Met-Enkephalinamide (300 µg/animal) induces analgesia in the hot plate and tail-flick tests in rats, effects that can be reversed by administration of the opioid receptor antagonist naloxone.3
1.Change, J.-K., and Fong, B.T.W.Opiate receptor affinities and behavioral effects of enkephalin: Structure-activity relationship of ten synthetic peptide analoguesLife Sci.18(12)1473-1481(1976) 2.Quinn, M.J., Laska, F.J., and Fennessy, M.R.Structure-activity relationships of met5- and leu5-enkephalin analoguesClin. Exp. Pharmacol. Physiol.6535-540(1979) 3.Yaksh, T.L., Huang, S.P., and Rudy, T.A.The direct and specific opiate-like effect of Met5-enkephalin and analogues on the spinal cordNeuroscience2(4)593-596(1977)