Striatal synaptosomal dopamine and serotonin cross-talk synthesis in aging rat.
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Date
2014-07
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Abstract
Aims: The existence of a dopamine (DA)-serotonin (5-HT) interaction in the brain has
been validated by numerous studies. Nevertheless, interaction between DA- 5-HT
synthesis in aging brain has not been highly considered. The central aim of this study was
to investigate the interaction between DA and 5-HT synthesis in rat brain striatal
synaptosomes.
Methodology: Male Wistar rats (3 and 30 months old) were killed by decapitation and the
brain sriatal synaptosomes were prepared by discontinuous Ficoll/sucrose gradient
technique. DA or 5-HT synthesized during an appropriate incubation period was measured
by the synaptosomes in the presence of added substrates (tyrosine or tryptophan) and a
monoamine oxidase inhibitor (pargiline).
Results: Dopamine synthesis in the synaptosomes prepared from young animals was
markedly inhibited (about 30%) by the addition of 5 μM 5-HT and increasing 5-HT up to 50
μM caused only a relatively small additional inhibition. However, different concentrations
of 5-HT (0-50μM) had little effect on dopamine synthesis of the synaptosomes
preparations from old animals. In case of 5-HT synthesis, exogenously added 5 μM DA
inhibited 5-HT synthesis in the synaptosomes of both ages by about 40%, whereas with
higher concentration of DA (10-50 μM) the rate of inhibition was highly pronounced in the
old rats as compared to that of young animals.
Conclusion: It is concluded that DA- 5-HT cross reaction might be considered, where long-term treatment with L-DOPA of patients suffering from Parkinson's disease renders
patients experience variations in response and even psychiatric problems.
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Keywords
Aging, dopamine synthesis, serotonin synthesis, synaptosomes, tryptophan hydroxylase, tyrosine hydroxylase
Citation
Mesripour Azadeh, Messripour Manoochehr. Striatal synaptosomal dopamine and serotonin cross-talk synthesis in aging rat. International Neuropsychiatric Disease Journal. 2014 Jul-Aug 2(4): 153-161.