title: Effects of systemic administration of beta-casomorphin-5 on learning and memory in mice.
abstract: The effects of systemic administration of bovine beta-casomorphin-5 (Tyr-Pro-Phe-Pro-Gly), a mu-opioid receptor agonist derived from milk beta-casein, on spontaneous alternation behavior in the Y-maze (spatial short-term memory) and step-down-type passive avoidance response (non-spatial long-term memory) were investigated in mice. Intraperitoneal (i.p.) administration of beta-casomorphin-5 (0.1-20 mg/kg) did not have a significant effect on either spontaneous alternation behavior or passive avoidance response. However, a low dose (1 mg/kg, i.p.) of beta-casomorphin-5 improved scopolamine (1 mg/kg, s.c.)-induced impairment of spontaneous alternation behavior and passive avoidance response. Pretreatment with intracerebroventricular injections of beta-funaltrexamine (a mu-opioid receptor antagonist, 0.1 microg/mouse) and naloxonazine (a mu(1)-opioid antagonist, 5 microg/mouse), which did not improve scopolamine-induced impairment, prevented the ameliorating effect of beta-casomorphin-5 on scopolamine-induced impairment of passive avoidance response. These results indicated that systemic administration of a low dose (1 mg/kg, i.p.) of beta-casomorphin-5 improves the disturbance of learning and memory resulting from cholinergic dysfunction through central mediation involving mu(1)-opioid receptors.
authors.affiliation: Laboratory of Cell Biology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan. sakaguti@gly.oups.ac.jp
authors.forename: Minoru
authors.initials: M
authors.lastname: Sakaguchi
authors.forename: Makoto
authors.initials: M
authors.lastname: Koseki
authors.forename: Masanori
authors.initials: M
authors.lastname: Wakamatsu
authors.forename: Eiko
authors.initials: E
authors.lastname: Matsumura
mesh_terms: D000700:Analgesics / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D002417:Cattle; D004305:Dose-Response Relationship, Drug; D004723:Endorphins / Q000008:administration & dosage / Q000494:pharmacology*; D007274:Injections, Intraperitoneal; D007276:Injections, Intraventricular; D007279:Injections, Subcutaneous; D008297:Male; D008568:Memory / Q000187:drug effects*; D051379:Mice; D009270:Naloxone / Q000031:analogs & derivatives / Q000494:pharmacology; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology*; D017450:Receptors, Opioid, mu / Q000819:agonists / Q000037:antagonists & inhibitors; D012601:Scopolamine / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D000700:Analgesics; D004723:Endorphins; D009292:Narcotic Antagonists; D010446:Peptide Fragments; D017450:Receptors, Opioid, mu; D009270:Naloxone; D009271:Naltrexone; C034812:beta-casomorphin 5; C024524:beta-funaltrexamine; C034643:naloxonazine; D012601:Scopolamine