title: Effects of beta-casomorphin-5 on passive avoidance response in mice.
abstract: The effects of intracerebroventricular (i.c.v.) injection of bovine beta-casomorphin-5 (beta-CM-5: Tyr-Pro-Phe-Pro-Gly), a micro-opioid agonist derived from milk beta-casein, on step-down type passive avoidance tasks were investigated in mice. Intracerebroventricular administration of a high dose (10 microg) of beta-CM-5 produced a significant decrease in step-down latency. beta-Funaltrexamine (5 microg, i.c.v.) almost completely reversed the beta-CM-5-induced shortening of step-down latency, although neither naltrindole (5 ng, i.c.v.) nor nor-binaltorphimine (5 microg, i.c.v.) had any significant influence on the effect of beta-CM-5. Meanwhile, a low dose (0.5 microg, i.c.v.) of beta-CM-5 inhibited scopolamine (1 mg/kg)-induced impairment of passive avoidance response. These results indicated that a high dose of beta-CM-5 induces amnesia, whereas a low dose ameliorates scopolamine-induced amnesia.
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 / Q000494:pharmacology; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology; D004723:Endorphins / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D007276:Injections, Intraventricular; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009271:Naltrexone / Q000031:analogs & derivatives* / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D010446:Peptide Fragments / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D011930:Reaction Time / Q000187:drug effects*; D012601:Scopolamine / Q000494:pharmacology
chemical_list: D000700:Analgesics; D004723:Endorphins; D009292:Narcotic Antagonists; D010446:Peptide Fragments; D009271:Naltrexone; C034812:beta-casomorphin 5; C024524:beta-funaltrexamine; D012601:Scopolamine