Studies on Active Trasport of L-Dopa (Dihydroxy-Phenylalanine) Into Brain Slices

Yoshida, Hiroshi; Namba, Jin; Kaniike, Kenichi; Imaizumi, Reiji

doi:10.1254/jjp.13.1

Cited by 17 publications

(8 citation statements)

References 23 publications

(15 reference statements)

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“…Conversion of dopa to dopamine and noradrenaline in brain slices and autoxida tion of dopa in the medium do not seem to have an important influence on amount of dopa accumulated in brain slices under our experimental conditions as pointed in our previous paper (1). In this paper it is shown that the major part of dopa in the slices is present in free form and binding of dopa with the intracellular particulate components does not seem to play an important role even in presence of ethanol.…”

Section: Discussionsupporting

confidence: 61%

“…Dopa is metabolized in brain slices , but the amount of dopa in the slices under our experimental condition is not so strongly depend on its metabolic destruction as described in our previous paper (1). Therefore, intra cellular distribution of dopa in brain slices was examined to know whether binding with particles concerned or not with the increase in amount of dopa accumulated in brain slices caused by ethanol.…”

Section: Intracellular Distribution Of Dopa In Brain Slicesmentioning

confidence: 80%

“…Brain cortex slices of adult guinea pigs were incubated at 37°C for 30 min with 0.1 mm L-dopa in glucose Ringer solution at pH 7.0, and then amount of dopa accumulated in the slices was estimated according to the methods described in our previous paper (1). In this experiments incubation tubes were closed with stoppers to prevent evapora tion of alcohol during incubation.…”

Section: Incubation Of Brain Slices With Dopymentioning

confidence: 99%

“…In our previous paper it was described that an amino acid, L-dopa (3,4-dihydroxy phenylalanine) was accumulated in brain slices against concentration gradient and an energy dependent active transport process was assumed to be participated in this pheno menon (1,4). The carrier system for this active transport of L-dopa was assumed to divide at least into two parts : a specific site to combine with L-dopa and the Na+, K+ -activated ATP-ase which seems to play a common important role for many active trans port processes.…”

mentioning

confidence: 99%

“…The carrier system for this active transport of L-dopa was assumed to divide at least into two parts : a specific site to combine with L-dopa and the Na+, K+ -activated ATP-ase which seems to play a common important role for many active trans port processes. Moreover it was discussed on a role of intracellular K+ concentration in this active transport process (1)(2)(3)(4).…”

mentioning

confidence: 99%

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Increase in Accumulation of L-Dopa (3,4-Dihydroxy-Phenylalanine) in Brain Slices by Alcohol

Kaniike

Yoshida

1963

Japanese Journal of Pharmacology

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Section: Discussionsupporting

confidence: 61%

Section: Intracellular Distribution Of Dopa In Brain Slicesmentioning

confidence: 80%

Section: Incubation Of Brain Slices With Dopymentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Increase in Accumulation of L-Dopa (3,4-Dihydroxy-Phenylalanine) in Brain Slices by Alcohol

Kaniike

Yoshida

1963

Japanese Journal of Pharmacology

Self Cite

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Monoamines in rat thyroid parafollicular cells and the effect of vitamin D2-induced degranulation

Dahlström

Ericson

1972

Z.Zellforsch

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Dopamine Synthesis by Non-Dopaminergic Neurons in the Arcuate Nucleus of Rat Fetuses

Melnikova

Lavrenteva

Кудрин

et al. 2005

Neurosci Behav Physiol

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The aim of the present work was to verify the hypothesis that non-dopaminergic neurons expressing individual complementary dopamine synthesis enzymes can perform the co-located synthesis of dopamine. According to this hypothesis, neurons expressing tyrosine hydroxylase use L-tyrosine for the synthesis of L-dihydroxyphenylalanine (L-DOPA), which then enters neurons expressing aromatic amino acid decarboxylase, which converts L-DOPA to dopamine. Experiments were performed using the mediobasal hypothalamus of rat fetuses, which mostly contains single-enzyme neurons (>99%) and occasional double-enzyme neurons (<1%). Controls were obtained from the fetal substantia nigra, which is enriched with dopaminergic neurons. High-performance liquid chromatography was used to measure levels of dopamine and L-DOPA in cell extracts and the incubation medium after incubation in the presence and absence of exogenous L-tyrosine. Addition of L-tyrosine to the medium led to increases in the level of synthesis and release of L-DOPA in the mediobasal hypothalamus and substantia nigra. In addition, L-tyrosine increased dopamine synthesis in the substantia nigra and decreased dopamine synthesis in the mediobasal hypothalamus. This regional difference in levels of dopamine synthesis is probably due to inhibition of the uptake of L-DOPA from the intercellular medium by neurons in the mediobasal hypothalamus containing aromatic amino acid decarboxylase, due to the competitive binding of the L-DOPA transporter by L-tyrosine. Thus, these results provide the first evidence for the co-located synthesis of dopamine by non-dopaminergic neurons expressing single complementary enzymes involved in the synthesis of this neurotransmitter.

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Studies on Active Trasport of L-Dopa (Dihydroxy-Phenylalanine) Into Brain Slices

Cited by 17 publications

References 23 publications

Increase in Accumulation of L-Dopa (3,4-Dihydroxy-Phenylalanine) in Brain Slices by Alcohol

Increase in Accumulation of L-Dopa (3,4-Dihydroxy-Phenylalanine) in Brain Slices by Alcohol

Monoamines in rat thyroid parafollicular cells and the effect of vitamin D2-induced degranulation

Dopamine Synthesis by Non-Dopaminergic Neurons in the Arcuate Nucleus of Rat Fetuses

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