title: Systemic and intracerebroventricular effects of opioid peptides in withdrawn morphine-dependent rhesus monkeys.
abstract: The effects of the degradation-resistant enkephalin analogs FK 33-824 and metkephamid were determined after systemic and intracerebroventricular (i.c.v.) administration in withdrawn morphine-dependent rhesus monkeys. Both peptides suppressed completely signs of 12-hr morphine deprivation, as does the prototype mu-receptor agonist morphine. The peptides were 100 and 2000 times more potent, respectively, after i.c.v. than s.c. injection. Thus, although peptidase-resistant, these compounds have restricted entrance into the central nervous system after systemic administration. The i.c.v. administration of compounds in rhesus monkeys should prove to be a valuable tool in the study of peptide ligands for opiate receptors.
mesh_terms: D000818:Animals; D005405:D-Ala(2),MePhe(4),Met(0)-ol-enkephalin / Q000008:administration & dosage / Q000494:pharmacology*; D004744:Enkephalin, Methionine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D006728:Hormones / Q000494:pharmacology*; D006801:Humans; D007276:Injections, Intraventricular; D007279:Injections, Subcutaneous; D008253:Macaca mulatta; D009020:Morphine / Q000494:pharmacology*; D009021:Morphine Dependence
chemical_list: D006728:Hormones; D004744:Enkephalin, Methionine; D005405:D-Ala(2),MePhe(4),Met(0)-ol-enkephalin; D009020:Morphine; C028208:metkephamid