title: Des-tyrosine(1) dynorphin A-(2-13) improves carbon monoxide-induced impairment of learning and memory in mice.
abstract: The effects of des-tyrosine(1) dynorphin A-(2-13) (dynorphin A-(2-13)) on carbon monoxide (CO)-induced impairment of learning and memory in mice were investigated using a Y-maze task and a passive avoidance test. The lower percentage alternation and shorter step-down latency of the CO-exposed group indicated that learning and/or memory impairment occurred in mice 5 and 7 days after CO exposure, respectively. Administration of dynorphin A-(2-13) (1.5 and/or 5.0 nmol/mouse, intracerebroventricularly (i.c.v.)) 30 min before behavioral tests improved the CO-induced impairment in alternation performance and the CO-induced shortened step-down latency. We previously reported that dynorphin A-(1-13) improved the impairment of learning and/or memory via kappa opioid receptor mediated mechanisms. To determine whether the effect of dynorphin A-(2-13) was also mediated via kappa opioid receptors, we attempted to block its action using a selective kappa opioid receptor antagonist, nor-binaltorphimine (nor-BNI). Nor-BNI (4.9 nmol/mouse, i.c.v.) did not block the effects of dynorphin A-(2-13) on the CO-induced impairment of learning and/or memory. These results indicate that dynorphin A-(2-13) improves impairment of learning and/or memory via a non-opioid mechanism.
authors.affiliation: Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Meijo University, 150 Yagotoyama, Tenpaku-ku, Nagoya, Japan. mhiramt@meijo-u.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Hiramatsu
authors.forename: K
authors.initials: K
authors.lastname: Inoue
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology; D002249:Carbon Monoxide Poisoning / Q000188:drug therapy*; D004399:Dynorphins / Q000494:pharmacology*; D008297:Male; D018782:Maze Learning / Q000187:drug effects* / Q000502:physiology*; D008568:Memory / Q000187:drug effects* / Q000502:physiology*; D051379:Mice; D008815:Mice, Inbred Strains; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D009292:Narcotic Antagonists / Q000494:pharmacology*; D009619:Nociceptors / Q000187:drug effects / Q000502:physiology; D010147:Pain Measurement; D010446:Peptide Fragments / Q000494:pharmacology*; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology
chemical_list: D009292:Narcotic Antagonists; D010446:Peptide Fragments; D004399:Dynorphins; C036730:dynorphin A, desTyr(1)-desTrp(14)-desAsp(15)-desAsn(16)-desGlu(17)-