Altered conditioned taste aversion and glucose utilization in related brain nuclei of diabetic GK rats

The impact of diabetes and especially hyperglycemia on brain glucose utilization and insulin binding are still not clear. This is probably due to the fact that most studies have been performed in streptozotocin treated rats that are highly hyperglycemia and that could have an effect per se on the brain. The aim of the present work was to measure, in vivo, glucose utilization and insulin binding in different areas of the brain of the spontaneously diabetic GK rats that present a moderate hyperglycemia. Brain insulin receptors number was not changed in the brain of GK rats. By contrast, an increased glucose utilization was present in the external plexiform and the intergranular layers of the olfactory bulbs, as well as in the amygdaloid of the GK rats. These structures are involved in conditioned taste aversion, which was found to be greatly altered in the diabetic rats. These results sustain the hypothesis of impaired neuropsychological functions in diabetic patients particularly in term of learning and memory.