Effects of dynorphin A (1-13) on carbon monoxide-induced delayed amnesia in mice.
The effects of dynorphin A (1-13) on carbon monoxide (CO)-induced amnesia in mice were investigated. Memory deficiency was apparent during Y-maze testing 5 days after CO exposure (delayed amnesia). Percent alternation in the CO-exposed group was significantly lower than that in the control group. Administration of dynorphin A (1-13) (1.5 nmol, i.c.v.) 15 min before the Y-maze test session reversed the impairment of spontaneous alternation performance in the CO-exposed group. To determine whether this effect was mediated via kappa opioid receptors, we attempted to block the effect of dynorphin A using the kappa opioid receptor antagonist nor-binaltorphimine. Nor-binaltorphimine (5.44 nmol, i.c.v.) blocked the effect of dynorphin A (1-13) on delayed amnesia. Dynorphin A (1-13) did not affect the impairment of alternation induced by the blockade of NMDA-receptors by dizocilpine (MK-801), but significantly prevented the impairment induced by mecamylamine. These results suggest that dynorphin A (1-13) modulates the kappa receptor-mediated opioid neuronal system, and reverses the impairment of spontaneous alternation performance induced by CO exposure.
Hiramatsu
M
M
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Meijo University, Nagoya, Japan.
Sasaki
M
M
Nabeshima
T
T
Kameyama
T
T
D000647:Amnesia / Q000139:chemically induced / Q000517:prevention & control* / Q000523:psychology; D000818:Animals; D002249:Carbon Monoxide Poisoning / Q000517:prevention & control* / Q000523:psychology*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004399:Dynorphins / Q000494:pharmacology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D007276:Injections, Intraventricular; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008464:Mecamylamine / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D009294:Narcotics / Q000494:pharmacology*; D018733:Nicotinic Antagonists / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D017473:Receptors, Opioid, kappa / Q000037:antagonists & inhibitors
D018691:Excitatory Amino Acid Antagonists; D009292:Narcotic Antagonists; D009294:Narcotics; D018733:Nicotinic Antagonists; D010446:Peptide Fragments; D016194:Receptors, N-Methyl-D-Aspartate; D017473:Receptors, Opioid, kappa; C051844:norbinaltorphimine; D009271:Naltrexone; D008464:Mecamylamine; D016291:Dizocilpine Maleate; C026843:dynorphin (1-13); D004399:Dynorphins