Abstract: Abundant evidence indicates that propofol profoundly affects memory processes, although its specifc effects on memory retrieval have not been clarifed. A recent study has indicated that hippocampal glycogen synthase kinase-3β (GSK-3β) activity affects memory. Constitutively active GSK-3β is required for memory retrieval, and propofol has been shown to inhibit GSK-3β. Tus, the present study examined whether propofol affects memory retrieval, and, if so, whether that effect is mediated through altered GSK-3β activity. Adult Sprague-Dawley rats were trained on a Morris water maze task (eight acquisition trials in one session) and subjected under the in?uence of a subhypnotic dose of propofol to a 24-hour probe trial memory retrieval test. Te results showed that rats receiving pretest propofol (25 mg/kg) spent signifcantly less time in the target quadrant but showed no change in locomotor activity compared with those in the control group. Memory retrieval was accompanied by reduced phosphorylation of the serine-9 residue of GSK-3β in the hippocampus, whereas phosphorylation of the tyrosine-216 residue was unaffected. However, propofol blocked this retrieval-associated serine-9 phosphorylation. Tese fndings suggest that subhypnotic propofol administration impairs memory retrieval and that the amnestic effects of propofol may be mediated by attenuated GSK-3β signaling in the hippocampus.

Key words: nerve regeneration, glycogen synthase kinase-3β, propofol, memory retrieval, Morris water maze, neural regeneration