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

Neurosci Lett. 2008 Jul 11;439(2):208-11. doi: 10.1016/j.neulet.2008.05.017. Epub 2008 May 10.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alzheimer Disease / chemically induced
  • Alzheimer Disease / complications
  • Amyloid beta-Peptides
  • Animals
  • Avoidance Learning / physiology*
  • Diet / methods*
  • Disease Models, Animal
  • Dopamine / metabolism*
  • Electrochemistry / methods
  • Hippocampus / metabolism
  • Learning Disabilities / etiology
  • Learning Disabilities / pathology
  • Male
  • Microdialysis / methods
  • Peptide Fragments
  • Rats
  • Reaction Time / drug effects
  • Reaction Time / physiology
  • Tyrosine 3-Monooxygenase / metabolism
  • Ventral Tegmental Area / metabolism


  • Amyloid beta-Peptides
  • Peptide Fragments
  • amyloid beta-protein (1-40)
  • Tyrosine 3-Monooxygenase
  • Dopamine