Enkephalins and selective analogues:mu-and delta-dependent opioid receptor interactions

摘要

Effects of enkephalins on spontaneous activity of smooth muscles of the gut and their opioid receptor preference are less investigated.The purpose of this study was to examine the effects of mu-opioid receptor selective enkephalin(enk)analogues [D-Ala~2,N-Me-L-Phe~4,Gly-ol~5](DAMGO)and [D-Ala~2,N-Me-L-Phe~4,Leu~5]erikephalyl-Arg-NH2,and delta-opioid analogues [Cys(O_2NH_2)~2,Leu~5]enk and [Cys(O_2NH_2)~2,Met~5]enk on the spontaneous contractions of guinea-pig ileum and to compare them with those of endogenous [Leu~5]enk and [Met~5]enk.To elucidate the character of the responses evoked by these peptides,we tested them in the presence of various blocking agents.The maximum relaxation or contraction(measured in mm and recalculated in mN),as a drug-evoked responses of the ileum preparations,was used as a criterion for the potency of the peptides tested.