Open Access
ARTICLE
Age related interaction of dopamine and serotonin synthesis in striatal synaptosomes
MANOOCHEHR MESSRIPOUR1, AZADEH MESRIPOUR2
1
Department of Medical Biochemistry, Khorasgan Branch, Islamic Azad University, Isfahan, Iran
2
Medical Plant Research Center, Shahre Kord University of Medical Sciences, Iran
* Address correspondence to: Manoochehr Messripour. Department of Medical Biochemistry, Khorasgan Branch, Islamic Azad University, Isfahan, IRAN
BIOCELL 2013, 37(2), 17-21. https://doi.org/10.32604/biocell.2013.37.017
Abstract
Tyrosine hydroxylase and tryptophan hydroxylase are key rate limiting enzymes in the biosynthesis of dopamine and serotonin, respectively. Since both enzymes are active in striatum, and affected by age,
this study was undertaken to investigate interaction between dopamine and serotonin synthesis in brain striatal
synaptosomes of aging rat. Male Wistar rats (3 and 30 month old) were killed by decapitation and brain striatal
synaptosomes were prepared by discontinuous Ficoll/sucrose gradient technique. Synaptosomes were incubated
in the presence of added pargiline (monoamineoxidase inhibitor), dopamine or serotonin synthesized during
25 min was measured by HPLC, employing electrochemical detection. Dopamine synthesis in synaptosomes
prepared from young animals was markedly inhibited by addition of 5 μM serotonin concentrations (30%)
and increasing serotonin concentrations up to 50 μM caused only a smaller additional inhibition. Dopamine
synthesis in synaptosomes obtained from old rats was signifi cantly lower than that of youg animals and addition
of serotonin concentrations up to 50 μM had little effect on these preparations. In case of serotonin synthesis,
exogenously added 5 μM dopamine inhibited serotonin synthesis in the synaptosomes of both ages by about
40%, whereas with higher concentration of dopamine (10-50 μM) the rate of inhibition was highly pronounced
in old rats as compared to that of young animals. It is concluded that dopamine and serotonin interaction may be
signifi cant, and that these should be considered in long-term treatments of Parkinson’s disease with L-DOPA.
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Cite This Article
MESSRIPOUR, M., MESRIPOUR, A. (2013). Age related interaction of dopamine and serotonin synthesis in striatal synaptosomes.
BIOCELL, 37(2), 17–21.
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