Dynorphin A-(1-13) markedly improves scopolamine-induced impairment of spontaneous alternation performance in mice.
The effect of intracerebroventricular (i.c.v.) injection of dynorphin A-(1-13) on the memory process was examined in mice, using spontaneous alternation performance related to working memory in a Y-maze. Dynorphin A-(1-13) (1, 3 and 10 micrograms) influenced neither spontaneous alternation performance nor total arm entries, which are considered to reflect locomotor activity. In contrast, dynorphin A-(1-13) (3 and 10 micrograms) significantly improved the impairment of spontaneously alternation performance induced by scopolamine (1 mg/kg s.c.). Simultaneously, the scopolamine-induced increase in total arm entries was markedly attenuated by dynorphin A-(1-13) (10 micrograms). The effect of dynorphin A-(1-13) (3 micrograms) on the scopolamine-induced impairment of spontaneous alternation was almost completely reversed by pretreatment with nor-binaltorphimine (4 micrograms i.c.v.), a kappa-selective opioid antagonist. These findings suggest that dynorphin A-(1-13) improves through the mediation of kappa-opioid receptors the scopolamine-induced impairment of spontaneous alternation performance associated with working memory.
Itoh
J
J
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Meijo University, Nagoya, Japan.
Ukai
M
M
Kameyama
T
T
D000704:Analysis of Variance; D000818:Animals; D004347:Drug Interactions; D004399:Dynorphins / Q000494:pharmacology*; D008297:Male; D008568:Memory / Q000187:drug effects*; D051379:Mice; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology*; D011597:Psychomotor Performance / Q000187:drug effects*; D017473:Receptors, Opioid, kappa / Q000037:antagonists & inhibitors; D012601:Scopolamine / Q000633:toxicity*
D010446:Peptide Fragments; D017473:Receptors, Opioid, kappa; C051844:norbinaltorphimine; D009271:Naltrexone; C026843:dynorphin (1-13); D004399:Dynorphins; D012601:Scopolamine