Cognitive and neurochemical alterations in hyperhomocysteinemic rat.

Accumulating data have shown that the level of serum homocysteine in patients with mild cognitive impairment, vascular dementia and Alzheimer's disease is higher than normal while the underlying mechanism is not fully understood. Here, a hyperhomocysteinemic rat model was made by maintaining rats on a diet high in methionine. The cognitive behavior, level of monoamine neurotransmitters in brain homogenates and brain-derived neurotrophic factor (BDNF) in cerebral spinal fluid (CSF) were compared between high-methionine diet and control group. The high-methionine diet group presented longer mean latency of escape and lesser time in target quadrant in morris maze test, lower level of serotonin and dopamine in cortex homogenates and lower level of BDNF in CSF. Together, our findings provide evidence that hyperhomocysteinemia could cause alterations of monoamine and neurotrophic factor, which might be further pathogenetic mechanisms underlying the cognitive deterioration.