Effects of opioid microinjections into the medial septal area on spatial memory in rats.
Recent work has demonstrated that posttraining systemic opioid antagonist administration facilitates the acquisition of a radial arm maze task in new spatial environments. In this study, we examined the effect of posttraining naloxone and beta-endorphin microinjections into the medial septal area on the acquisition of a radial maze task in new spatial environments. The results of these experiments demonstrated that posttraining intraseptal naloxone administration facilitated, whereas posttraining intraseptal beta-endorphin administration impaired, the acquisition of criterion performance on a maze task performed in new spatial environments. Further, intraventricular beta-endorphin administration did not produce effects that were comparable to those observed following intraseptal beta-endorphin administration, which indicates that the septal region is a brain site that is sensitive to the effects of opioids on spatial memory in new environments. Further, posttraining intraseptal beta-endorphin administration had no effect on working memory in a familiar spatial environment, whereas pretraining intraseptal beta-endorphin administration had no effect on the performance of a previously acquired spatial task.
Bostock
E
E
Psychology Department, University of North Carolina-Chapel Hill.
Gallagher
M
M
King
R A
RA
D000818:Animals; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology; D004723:Endorphins / Q000494:pharmacology* / Q000502:physiology; D007276:Injections, Intraventricular; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D008845:Microinjections; D009270:Naloxone / Q000494:pharmacology*; D051381:Rats; D012686:Septal Nuclei / Q000187:drug effects / Q000502:physiology*; D013037:Spatial Behavior / Q000187:drug effects / Q000502:physiology*
D004723:Endorphins; D009270:Naloxone