Unlike beta-endorphin, dynorphin 1-13 does not cause retrograde amnesia for shuttle avoidance or inhibitory avoidance learning in rats.
Posttraining administration of the opioid peptides, beta-endorphin or the enkephalins, is known to cause retrograde amnesia for a variety of tasks in rats. The present paper studies the effect of the posttraining administration of dynorphin 1-13 on retention of a step-down inhibitory avoidance task and of a shuttle avoidance task. For the purpose of comparison, the effect of human beta-endorphin was also studied. In confirmation of previous results, beta-endorphin (1.0 or 10.0 micrograms/kg, IP) caused retrograde amnesia for the two tasks. Dynorphin 1-13 had no effect at doses between 0.008-125.0 micrograms/kg IP or 1.25-125.0 ng/rat ICV in the inhibitory avoidance task, or at doses of 5.0, 25.0, or 125.0 micrograms/kg in the shuttle avoidance paradigm. These findings suggest that, in contrast to beta-endorphin, dynorphin 1-13 may not be involved in memory regulation at the posttraining period in rats.
Izquierdo
I
I
De Almeida
M A
MA
Emiliano
V R
VR
D000647:Amnesia / Q000139:chemically induced*; D000648:Amnesia, Retrograde / Q000139:chemically induced*; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D004399:Dynorphins / Q000494:pharmacology*; D004723:Endorphins / Q000494:pharmacology*; D005260:Female; D007274:Injections, Intraperitoneal; D007276:Injections, Intraventricular; D009294:Narcotics / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D001615:beta-Endorphin
D004723:Endorphins; D009294:Narcotics; D010446:Peptide Fragments; D001615:beta-Endorphin; C026843:dynorphin (1-13); D004399:Dynorphins