Dynorphin1-17 can enhance or impair retention of an inhibitory avoidance response in rats.
The possible effects of subcutaneous administration of dynorphin1-17 on retention of an inhibitory avoidance behavior have been studied in rats. Post-training or pre-test administration of dynorphin1-17 in doses of 25 or 50 micrograms/kg facilitated retention performance in rats subjected to a footshock of 0.2 mA n the acquisition trial. However, the same doses of the opioid peptide exerted a deleterious effect on retention performance when a footshock of 0.4 mA was used after either post-training or pre-test administration. Post-training injection of the kappa-receptor antagonist MR-2266 in doses of 0.5, 1 or 2.5 mg/kg failed to affect retention behavior. However, the previous administration of 2.5 mg/kg of MR-2266 prevented the facilitatory effect exerted by dynorphin1-17 after post-training, as well as after pre-test administration. Our results suggest that dynorphin1-17 may be involved in modulating the consolidation, as well as the retrieval, of recently acquired information.
del Cerro
S
S
Department of Psychobiology, C.S.I.C., Madrid, Spain.
Borrell
J
J
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D001575:Benzomorphans / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004399:Dynorphins / Q000008:administration & dosage / Q000494:pharmacology*; D007279:Injections, Subcutaneous; D008297:Male; D008568:Memory / Q000187:drug effects*; D009292:Narcotic Antagonists / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000187:drug effects / Q000502:physiology; D017473:Receptors, Opioid, kappa; D012016:Reference Values
D001575:Benzomorphans; D009292:Narcotic Antagonists; D011957:Receptors, Opioid; D017473:Receptors, Opioid, kappa; C027247:MR 2266; D004399:Dynorphins