Elevated homocysteine (Hcy) plasma levels have been associated with several psychiatric and neurodegenerative disorders including depression, schizophrenia, Alzheimer’s disease, and Parkinson’s disease. Flinders Line rats present two groups: Flinders Sensitive Line (FSL) and Flinders Resistant Line (FRL). FSL rats were originally bred for increased responses to an anticholinesterase agent. FSL rats partially resembles depressed individuals because they exhibit reduced appetite and psychomotor function, sleep and immune abnormalities observed in depressed individuals and they have been very effective in detecting antidepressive drugs. FRL rats present high resistance to an anticholinesterase agent, this group is a FSL control. The main objective of this study was to verify homocysteine and cysteine plasma concentrations, as well as vitamins involved in their metabolism in the Flinders Line rats.
FSL and FRL rats had not been submitted to any manipulation. Homocysteine and cysteine values were determined in plasma by high performance liquid chromatography (HPLC) with fluorimetric detection and isocratic elution. Folate and B6 vitamin were quantified in serum using HPLC with ultraviolet detection (UV) and isocratic elution.
Homocysteine and cysteine concentrations did not have significant difference between FSL and FRL. FSL animals presented decreased concentrations of folate when compared to FRL animals (p<0.01). Concentrations of B6 vitamin were also significantly lower in FSL animals (p<0.05).
Our results suggest that low folate and B6 vitamin concentrations in FSL rats can be related to the depressive behavior of these animals. Both folate and B6 vitamin are important cofactors in the synthesis of the neurotransmitters involved in the pathophisiology of depression.
Financial support: FAPESP, CNPq, AFIP