Age-related Changes in the Insulin Receptor β in the Gerbil Hippocampus

초록

The insulin receptor has been reported to be associated with memory formation via the hippocampus. In this study, we observed age-related changes in the insulin receptor beta immunoreactivity and its protein levels in the hippocampus of gerbils of various ages in order to identify the correlation between the insulin receptor beta and aging processes in the hippocampus. Insulin receptor beta immunoreactivity was mainly detected in the molecular and polymorphic layers of the dentate gyrus, and in mossy fibers, Schaffer collaterals, alveus and stratum lacunosum-moleculare of the hippocampus proper (CA1-3) of gerbils at postnatal month 1 (PM 1). Insulin receptor beta immunoreactivity decreased with age in all of these structures, except for the alveus. Reduction of the insulin receptor beta immunoreactivity was prominent in the molecular layer of the dentate gyrus at PM 6 and in the stratum lacunosum-moleculare of the CA1 region at PM 12, while insulin receptor beta immunoreactivity was decreased in other regions in the PM 18 groups. In addition, insulin receptor beta protein level in the whole hippocampus was slightly increased at PM 3, and it decreased in an age-dependent manner from PM 6 to PM 24. These reductions of the insulin receptor beta in the hippocampus may be associated with age-related memory deficits in gerbils.

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