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Brodnik ZD, Double M, España RA, Jaskiw GE. L-Tyrosine availability affects basal and stimulated catecholamine indices in prefrontal cortex and striatum of the rat. Neuropharmacology 2017; 123:159-174. [PMID: 28571714 DOI: 10.1016/j.neuropharm.2017.05.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 05/22/2017] [Accepted: 05/26/2017] [Indexed: 12/15/2022]
Abstract
We previously found that L-tyrosine (L-TYR) but not D-TYR administered by reverse dialysis elevated catecholamine synthesis in vivo in medial prefrontal cortex (MPFC) and striatum of the rat (Brodnik et al., 2012). We now report L-TYR effects on extracellular levels of catecholamines and their metabolites. In MPFC, reverse dialysis of L-TYR elevated in vivo levels of dihydroxyphenylacetic acid (DOPAC) (L-TYR 250-1000 μM), homovanillic acid (HVA) (L-TYR 1000 μM) and 3-methoxy-4-hydroxyphenylglycol (MHPG) (L-TYR 500-1000 μM). In striatum L-TYR 250 μM elevated DOPAC. We also examined L-TYR effects on extracellular dopamine (DA) and norepinephrine (NE) levels during two 30 min pulses (P2 and P1) of K+ (37.5 mM) separated by t = 2.0 h. L-TYR significantly elevated the ratio P2/P1 for DA (L-TYR 125 μM) and NE (L-TYR 125-250 μM) in MPFC but lowered P2/P1 for DA (L-TYR 250 μM) in striatum. Finally, we measured DA levels in brain slices using ex-vivo voltammetry. Perfusion with L-TYR (12.5-50 μM) dose-dependently elevated stimulated DA levels in striatum. In all the above studies, D-TYR had no effect. We conclude that acute increases within the physiological range of L-TYR levels can increase catecholamine metabolism and efflux in MPFC and striatum. Chronically, such repeated increases in L-TYR availability could induce adaptive changes in catecholamine transmission while amplifying the metabolic cost of catecholamine synthesis and degradation. This has implications for neuropsychiatric conditions in which neurotoxicity and/or disordered L-TYR transport have been implicated.
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Affiliation(s)
- Zachary D Brodnik
- Drexel University College of Medicine, Department of Neurobiology and Anatomy, 2900 W. Queen Lane, Philadelphia, PA 19129, United States
| | - Manda Double
- Medical Research Service, Louis Stokes Cleveland DVAMC, 10701 East Blvd., Cleveland, OH 44106, United States
| | - Rodrigo A España
- Drexel University College of Medicine, Department of Neurobiology and Anatomy, 2900 W. Queen Lane, Philadelphia, PA 19129, United States
| | - George E Jaskiw
- Medical Research Service, Louis Stokes Cleveland DVAMC, 10701 East Blvd., Cleveland, OH 44106, United States; Dept. of Psychiatry, Case Western University Medical Center at W.O. Walker 10524 Euclid Ave, Cleveland, OH 44133, United States.
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Kozina EA, Kim AR, Kurina AY, Ugrumov MV. Cooperative synthesis of dopamine by non-dopaminergic neurons as a compensatory mechanism in the striatum of mice with MPTP-induced Parkinsonism. Neurobiol Dis 2016; 98:108-121. [PMID: 27940203 DOI: 10.1016/j.nbd.2016.12.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 12/01/2016] [Accepted: 12/02/2016] [Indexed: 10/20/2022] Open
Abstract
Since the late 80s it has been repeatedly shown that besides dopaminergic neurons, the brain contains so-called monoenzymatic neurons possessing one of the enzymes of dopamine (DA) synthesis, tyrosine hydroxylase (TH) or aromatic l-amino acid decarboxylase (AADC). However, the data on the existence of monoenzymatic neurons in the striatum remain controversial, and little is known about their functional significance. The aim of this study was to test our hypothesis that monoenzymatic TH-containing neurons produce DA in cooperation with the neurons containing AADC, which might help to compensate DA deficiency under the failure of the nigrostriatal dopaminergic system. Using a combination of techniques: retrograde tracing, qPCR and immunolabeling for TH, AADC and MAP2, we showed that the striatum of mice with normal and degraded dopaminergic system comprises of monoenzymatic TH- and AADC-containing neurons. To provide evidence for cooperative synthesis of DA, we used an ex vivo model of inhibiting of DA synthesis by blocking transport of l-DOPA, produced in monoenzymatic TH-containing neurons, to neurons containing AADC by means of l-leucine, a competitive inhibitor of the membrane transporter of large neutral amino acids, and l-DOPA. With this original approach, cooperative synthesis of DA in the striatum was proven in MPTP-treated mice but not in the control. Furthermore, we demonstrated that the proportion of DA produced through cooperative synthesis in the striatum of MPTP-treated mice increases as the degradation of dopaminergic system proceeds. An increase in the proportion of cooperative synthesis of DA alongside degradation of the dopaminergic system is also proved by an increase of both TH gene expression and the number of TH-immunoreactive structures in the striatum. Thus, these data suggest that the cooperative synthesis of DA in the degraded striatum is an up-regulated compensatory reaction, which plays an increasing role as DA deficiency rises, and might be considered among the principal mechanisms of neuroplasticity in neurodegenerative diseases.
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Affiliation(s)
- Elena A Kozina
- Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology RAS, 26 Vavilov St, Moscow 119334, Russia
| | - Aleksandr R Kim
- Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology RAS, 26 Vavilov St, Moscow 119334, Russia
| | - Anna Y Kurina
- Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology RAS, 26 Vavilov St, Moscow 119334, Russia
| | - Michael V Ugrumov
- Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology RAS, 26 Vavilov St, Moscow 119334, Russia; Department of Psychology, Faculty of Social Sciences, The National Research University Higher School of Economics, 20 Myasnitskaya St, Moscow 101000, Russia.
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Ugrumov M, Taxi J, Pronina T, Kurina A, Sorokin A, Sapronova A, Calas A. Neurons expressing individual enzymes of dopamine synthesis in the mediobasal hypothalamus of adult rats: functional significance and topographic interrelations. Neuroscience 2014; 277:45-54. [PMID: 24997271 DOI: 10.1016/j.neuroscience.2014.06.051] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Revised: 06/20/2014] [Accepted: 06/24/2014] [Indexed: 11/30/2022]
Abstract
Besides dopaminergic (DA-ergic) neurons having all enzymes of DA synthesis, tyrosine hydroxylase (TH) and aromatic l-amino acid decarboxylase (AADC), "monoenzymatic" neurons expressing only one of them were found in the brain, mostly in the mediobasal hypothalamus (MBH). The aim of this study was to test our hypothesis that DA is synthesized by monoenzymatic neurons, i.e. l-3,4-dihydroxyphenylalanine (l-DOPA), which produced in the monoenzymatic TH neurons is transported in the monoenzymatic AADC neurons for DA synthesis. Incubation of MBH in Krebs-Ringer solution with l-leucine, a competitive inhibitor of l-DOPA uptake, was used to prevent a hypothetical l-DOPA capture into AADC-containing neurons. Incubation of the substantia nigra containing DA-ergic neurons under the same conditions served as the control. According to our data, the l-leucine administration provoked a decrease of DA concentration in MBH and in the incubation medium but not in the substantia nigra and respective incubation medium, showing a decrease of cooperative synthesis of DA in MBH. This conclusion was supported by an observation of higher concentration of l-DOPA in the incubation medium under perfusion of MBH with Krebs-Ringer solution containing tolcapone, an inhibitor of catechol-O-methyltransferase, and l-leucine than under perfusion with the same solution, but without l-leucine. Functional interaction between monoenzymatic TH and AADC neurons was indirectly confirmed by finding in electron microscopy their close relations in MBH. Besides monoenzymatic AADC neurons, any AADC-possessing neurons, catecholaminergic and serotoninergic, apparently, could participate in DA synthesis together with monoenzymatic TH neurons. This idea was confirmed by the observation of close topographic relations between monoenzymatic TH neurons and those containing both enzymes, i.e. DA-ergic, noradrenergic or adrenergic. Thus, monoenzymatic neurons possessing TH or AADC and being in close topographic relations can synthesize DA in cooperation.
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Affiliation(s)
- M Ugrumov
- Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov St., Moscow 119334, Russia.
| | - J Taxi
- Laboratoire de Pathophysiologie des maladies du système nervoux central, UMR5 INSERM 952, IFR 83, Université P. et M. Curie, 7 quai St. Bernard, 75252 Paris Cedex 05, France
| | - T Pronina
- Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov St., Moscow 119334, Russia
| | - A Kurina
- Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov St., Moscow 119334, Russia
| | - A Sorokin
- Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov St., Moscow 119334, Russia; Laboratoire de Pathophysiologie des maladies du système nervoux central, UMR5 INSERM 952, IFR 83, Université P. et M. Curie, 7 quai St. Bernard, 75252 Paris Cedex 05, France
| | - A Sapronova
- Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov St., Moscow 119334, Russia
| | - A Calas
- IINS, UMR CNRS 5297, Université Bordeaux Segalen, 146 rue Léo Saignat, 33076 Bordeaux-Cedex, France
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Ugrumov MV. Brain neurons partly expressing dopaminergic phenotype: location, development, functional significance, and regulation. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2013; 68:37-91. [PMID: 24054140 DOI: 10.1016/b978-0-12-411512-5.00004-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In addition to catecholaminergic neurons possessing all the enzymes of catecholamine synthesis and the specific membrane transporters, neurons partly expressing the catecholaminergic phenotype have been found a quarter of a century ago. Most of them express individual enzymes of dopamine (DA) synthesis, tyrosine hydroxylase (TH), or aromatic l-amino acid decarboxylase (AADC), lacking the DA membrane transporter and the vesicular monoamine transporter, type 2. These so-called monoenzymatic neurons are widely distributed throughout the brain in ontogenesis and adulthood being in some brain regions even more numerous than dopaminergic (DA-ergic) neurons. Individual enzymes of DA synthesis are expressed in these neurons continuously or transiently in norm and pathology. It has been proven that monoenzymatic TH neurons and AADC neurons are capable of producing DA in cooperation. It means that l-3,4-dihydroxyphenylalanine (l-DOPA) synthesized from l-tyrosine in monoenzymatic TH neurons is transported to monoenzymatic AADC neurons for DA synthesis. Such cooperative synthesis of DA is considered as a compensatory reaction under a failure of DA-ergic neurons, for example, in neurodegenerative diseases like hyperprolactinemia and Parkinson's disease. Moreover, l-DOPA, produced in monoenzymatic TH neurons, is assumed to play a role of a neurotransmitter or neuromodulator affecting the target neurons via catecholamine receptors. Thus, numerous widespread neurons expressing individual complementary enzymes of DA synthesis serve to produce DA in cooperation that is a compensatory reaction at failure of DA-ergic neurons.
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Affiliation(s)
- Michael V Ugrumov
- Institute of Developmental Biology and Centre for Brain Research, Russian Academy of Sciences, Moscow, Russia; Institute of Normal Physiology RAMS, Moscow, Russia.
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Jaskiw GE, Newbould E, Bongiovanni R. Tyrosine availability modulates potassium-induced striatal catecholamine efflux in vivo. Brain Res 2008; 1209:74-84. [DOI: 10.1016/j.brainres.2008.02.050] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Revised: 02/14/2008] [Accepted: 02/15/2008] [Indexed: 11/17/2022]
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Blokland A, Lieben C, Deutz NEP. Anxiogenic and depressive-like effects, but no cognitive deficits, after repeated moderate tryptophan depletion in the rat. J Psychopharmacol 2002; 16:39-49. [PMID: 11949770 DOI: 10.1177/026988110201600112] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The tryptophan (TRP) depletion method has been used as a tool to investigate the effects of acute lowered serotonin levels in the brain. In the present study, the effects of this treatment were investigated in rat models of anxiety (open field test, home cage emergence test), depression (forced swimming test, sucrose preference test) and cognition (spatial discrimination learning, sustained attention). It was found that the repeated TRP depletion increased anxiety-related behaviour in the open field test and increased immobility in the forced swimming test. The other behavioural tests did not reveal effects of treatment. TRP levels were decreased in plasma (34%) and hippocampus (33%) but not in the cortex. Stress-induced corticosterone levels were not affected after TRP depletion. The present findings indicate that repeated moderate TRP depletion leads to anxiogenic and depressive-like behaviour in the rat and corroborates the notion of the involvement of serotonin in these behaviours.
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Affiliation(s)
- Arjan Blokland
- Faculty of Psychology, Maastricht Brain and Behaviour Institute, Maastricht University, The Netherlands.
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