Insulin modulates hippocampally-mediated spatial working memory via glucose transporter-4.

Insulin modulates hippocampally-mediated spatial working memory via glucose transporter-4.
Behav Brain Res. 2017 Sep 21;:
Authors: Pearson-Leary J, Jahagirdar V, Sage J, McNay EC
Abstract
The insulin-regulated glucose transporter, GluT4, is a key molecule in peripheral insulin signaling. Although GluT4 is abundantly expressed in neurons of specific brain regions such as the hippocampus, the functional role of neuronal GluT4 is unclear. Here, we used pharmacological inhibition of GluT4-mediated glucose uptake to determine whether GluT4 mediates insulin-mediated glucose uptake in the hippocampus. Consistent with previous reports, we found that glucose utilization increased in the dorsal hippocampus of male rats during spontaneous alternation (SA), a hippocampally-mediated spatial working memory task. We previously showed that insulin signaling within the hippocampus is required for processing this task, and that administration of exogenous insulin enhances performance. At baseline levels of hippocampal insulin, inhibition of GluT4-mediated glucose uptake did not affect SA performance. However, inhibition of an upstream regulator of GluT4, Akt, did impair SA performance. Conversely, when a memory-enhancing dose of insulin was delivered to the hippocampus prior to SA-testing, inhibition of GluT4-mediated glucose transport prevented cognitive enhancement. These data suggest that baseline hippocampal cognitive processing does not require f...

Source: Behavioural Brain Research - September 21, 2017 Category: Neurology Authors: Pearson-Leary J, Jahagirdar V, Sage J, McNay EC Tags: Behav Brain Res Source Type: research