Cyclic polypeptides having mu-receptor specificity

Abstract

Novel compounds which are capable of binding with enhanced specificity to the mu opioid receptor are disclosed. The compounds are analogs of somatostain and have the formula: ##STR1## wherein X is CONH.sub.2 or CH.sub.2 OH; Y and Z are independently sulfur or CH.sub.2 ; R.sup.1 and R.sup.2, which may be the same or different, are hydrogen, methyl, ethyl, cyclopentamethylene, or a lower alkyl group having five or less carbon atoms; R.sup.3 and R.sup.4, which may be the same or different, are hydrogen, methyl, ethyl, cyclopentamethylene, or a lower alkyl group having five or less carbon atoms, provided, however, that R.sup.1, R.sup.2, R.sup.3, and R.sup.4 may not all be hydrogen; AA.sub.1 is Phe, D-Phe, phenyl-Gly, D-phenyl-Gly, Tyr, D-Tyr, L-1-Naphthylalanine, D-1-Naphthylalanine, or D-Phe(4-Me); AA.sub.2 is Tyr, Phe, Tyr(OMe), Phe(4-Me), Tyr(OEt), or Phe(4-Et); and AA.sub.3 is Lys, Arg, Orn or homo-Arg. The novel compounds have antagonist activity and may be used to induce pharmacological or therapeutic effects in humans and other animals.

Dependencies are inferred from the claim text.