Elsevier

Neuroscience Letters

Volume 439, Issue 2, 11 July 2008, Pages 208-211
Neuroscience Letters

Soft-diet feeding decreases dopamine release and impairs aversion learning in Alzheimer model rats

https://doi.org/10.1016/j.neulet.2008.05.017Get rights and content

Abstract

To examine the effects of soft-diet feeding on the dopaminergic system in a model rat for Alzheimer's disease (AD), we measured dopamine release in the hippocampus using a microdialysis approach and assessed learning ability and memory using step-through passive avoidance tests. Furthermore, we immunohistochemically examined the ventral tegmental area (VTA), which is the origin of hippocampal dopaminergic fibers using tyrosine hydroxylase (TH), a marker enzyme for the dopaminergic nervous system. Feeding a soft diet decreased dopamine release in the hippocampus and impaired learning ability and memory in AD model rats in comparison with rats fed a hard diet; however, TH-immunopositive profiles in the VTA seemed not to be notably different between rats fed a soft diet and those fed a hard diet. These observations suggest that soft-diet feeding enhances the impairment of learning ability and memory through the decline of dopamine release in the hippocampus in AD rats.

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Acknowledgements

We express our thanks to Dr. Toshitaka Nabeshima (Department of Chemical Pharmacology, Graduate School of Pharmaceutical Science, Meijo University, Nagoya, Japan) and Dr Atsumi Nitta (Department of Neuropsychopharmacology and Hospital Pharmacy, School of Medicine, Nagoya University, Nagoya, Japan) for instruction on how to infuse rats with amyloid-β peptide. This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture of Japan

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