Abstract
Nitric oxide synthase inhibitors reduce l-3, (Del-Bel et al., Cell Mol Neurobiol 25(2):371–392, 2005) 4-dihydroxyphenylalanine (l-DOPA)-induced abnormal motor effects subsequent to depletion of dopaminergic neurons in rodents and non-human primates. The present study used quantitative high-performance liquid chromatography to analyze, for the first time, dopamine metabolism in striatum of rats in order to elucidate the mechanism of action of the nitric oxide synthase inhibitors. Adult male Wistar rats received unilateral microinjection of saline (sham) or 6-hydroxydopamine (6-OHDA-lesioned) in the medial forebrain bundle. Past 3 weeks, rats were treated during 21 days with l-DOPA/benserazide (30 mg/kg/7.5 mg/kg, respectively, daily). On the 22nd day rats received an intraperitoneal (i.p.) injection of either vehicle or 7-nitroindazole, a preferential neuronal nitric oxide synthase inhibitor before l-DOPA. Abnormal involuntary movements and rotarod test were assessed as behavioral correlate of motor responses. Lesion intensity was evaluated through tyrosine hydroxylase immunohystochemical reaction. Dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), and an extent of dopamine striatal tissue levels/dopamine metabolism were measured in the striatum. Lesion with 6-OHDA decreased dopamine, DOPAC, and DOPAC/dopamine ratio in the lesioned striatum. l-DOPA treatment induced abnormal involuntary movements and increased DOPAC/dopamine ratio (nearly five times) in the lesioned striatum. l-DOPA-induced dyskinesia was mitigated by 7-nitroindazole, which also decreased dopamine turnover, dopamine and DOPAC levels. Our results revealed an almost two times increase in dopamine content in the non-lesioned striatum of 6-OHDA-lesioned rats. Reduction of striatal DOPAC/dopamine ratio in dyskinetic rats may suggest an increase in the dopamine availability. Our data confirm contribution of nitrergic transmission in the pathogenesis of l-DOPA-induced dyskinesia with potential utilization of nitric oxide synthase inhibitors for treatment.
Similar content being viewed by others
Abbreviations
- 7-NI:
-
7-Nitroindazole
- 6-OHDA:
-
6-Hydroxydopamine
- AIMs:
-
Abnormal involuntary movements
- cGMP:
-
Cyclic guanosine monophosphate
- DAT:
-
Dopamine transporter
- DOPAC:
-
3,4-Dihydroxyphenylacetic acid
- GABA:
-
Gamma-aminobutyric acid
- l-NAME:
-
N G-nitro-l-arginine methyl ester
- nNOS:
-
Neuronal nitric oxide synthase
- NOS:
-
Nitric oxide synthase
- NMDA:
-
N-Methyl-d-aspartate acid
- NADPH:
-
Nicotinamide adenine dinucleotide phosphate
- SN:
-
Substantia nigra
- VTA:
-
Ventral tegmental area
- TH:
-
Tyrosine hydroxylase
References
Altar CA, Marien MR, Marshall JF (1987) Time course of adaptations in dopamine biosynthesis, metabolism, and release following nigrostriatal lesions: implications for behavioral recovery from brain injury. J Neurochem 48(2):390–399
Archer T, Kostrzewa RM, Beninger RJ, Palomo T (2011) Staging neurodegenerative disorders: structural, regional, biomarker, and functional progressions. Neurotox Res 19(2):211–234
Bergstrom BP, Garris PA (2003) Passive stabilization of striatal extracellular dopamine across the lesion spectrum encompassing the presymptomatic phase of Parkinson’s disease: a voltammetric study in the 6-OHDA-lesioned rat. J Neurochem 87(5):1224–1236
Bezard E, Gross CE, Brotchie JM (2003) Presymptomatic compensation in Parkinson’s disease is not dopamine-mediated. Trends Neurosci 26(4):215–221
Bianco LE, Wiesinger J, Earley CJ, Jones BC, Beard JL (2008) Iron deficiency alters dopamine uptake and response to l-DOPA injection in Sprague–Dawley rats. J Neurochem 106(1):205–215
Boireau A, Dubedat P, Bordier F, Imperato A, Moussaoui S (2000) The protective effect of riluzole in the MPTP model of Parkinson’s disease in mice is not due to a decrease in MPP(+) accumulation. Neuropharmacology 39(6):1016–1020
Bradford MM (1976) A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein–dye binding. Anal Biochem 72:248–254
Brotchie J, Fitzer-Attas C (2009) Mechanisms compensating for dopamine loss in early Parkinson disease. Neurology 72(7 Suppl):S32–S38
Brun Y, Karachi C, Fernandez-Vidal S, Jodoin N, Grabli D, Bardinet E, Mallet L, Agid Y, Yelnik J, Welter ML (2012) Does unilateral basal ganglia activity functionally influence the contralateral side? What we can learn from STN stimulation in patients with Parkinson’s disease. J Neurophysiol 108(6):1575
Calon F, Morissette M, Rajput AH, Hornykiewicz O, Bédard PJ, Di Paolo T (2003) Changes of GABA receptors and dopamine turnover in the postmortem brains of parkinsonians with levodopa-induced motor complications. Mov Disord 18(3):241–253
Cao X, Yasuda T, Uthayathas S, Watts RL, Mouradian MM, Mochizuki H, Papa SM (2010) Striatal overexpression of DeltaFosB reproduces chronic levodopa induced involuntary movements. J Neurosci 30:7335–7343
Castagnoli K, Palmer S, Anderson A, Bueters T, Castagnoli N (1997) The neuronal nitric oxide synthase inhibitor 7-nitroindazole also inhibits the monoamine oxidase-B-catalyzed oxidation of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Chem Res Toxicol 10(4):364–368
Cenci MA, Ohlin KE (2009) Rodent models of treatment-induced motor complications in Parkinson’s disease. Parkinsonism Relat Disord 15(Suppl 4):S13–S17
Cenci MA, Tranberg A, Andersson M, Hilbertson A (1999) Changes in the regional and compartmental distribution of FosB- and JunB-like immunoreactivity induced in the dopamine-denervated rat striatum by acute or chronic L-dopa treatment. Neuroscience 94(2):515–527
Chalimoniuk M, Langfort J (2007) The effect of subchronic, intermittent l-DOPA treatment on neuronal nitric oxide synthase and soluble guanylyl cyclase expression and activity in the striatum and midbrain of normal and MPTP-treated mice. Neurochem Int 50(6):821–833
Chalimoniuk M, Stepień A (2004) Influence of the therapy with pergolide mesylate plus l-DOPA and with l-DOPA alone on serum cGMP level in PD patients. Pol J Pharmacol 56(5):647–650
Chalimoniuk M, Stepień A, Strosznajder JB (2004) Pergolide mesylate, a dopaminergic receptor agonist, applied with l-DOPA enhances serum antioxidant enzyme activity in Parkinson disease. Clin Neuropharmacol 27:223–229
Cooper JR, Bloom FE, Roth RH (1996) The biochemical basis of neuropharmacology. Oxford University Press, New York, pp 293–351
de la Fuente-Fernández R, Sossi V, Huang Z, Furtado S, Lu JQ, Calne DB, Ruth TJ, Stoessl AJ (2004) Levodopa-induced changes in synaptic dopamine levels increase with progression of Parkinson’s disease: implications for dyskinesias. Brain. 127(Pt 12):2747–2754
Del-Bel EA, da Silva CA, Guimaraes FS (1998) Catalepsy induced by nitric oxide synthase inhibitors. Gen Pharmacol 30:245–248
Del-Bel EA, da Silva CA, Guimaraes FS, Bermudez-Echeverry M (2004) Catalepsy induced by intra-striatal administration of nitric oxide synthase inhibitors in rats. Eur J Pharmacol 485:175–181
Del-Bel EA, Guimaraes FS, Bermudez-Echeverry M, Gomes MZ, Schiaveto-de-Souza A, Padovan-Neto F, Tumas V, Barion-Cavalcanti AP, Lazzarini M, Nucci-da-Silva LP, de Paula-Souza D (2005) Role of nitric oxide on motor behavior. Cell Mol Neurobiol 25(2):371–392
Del-Bel EA, Guimaraes FS, Joca SR, Echeverry MB, Ferreira FR (2010) Tolerance to the cataleptic effect that follows repeated nitric oxide synthase inhibition may be related to functional enzymatic recovery. J Psychopharmacol 24:397–405
Del-Bel E, Padovan-Neto FE, Raisman-Vozari R, Lazzarini M (2011) Role of nitric oxide in motor control: implications for Parkinson’s disease pathophysiology and treatment. Curr Pharm Des 17(5):471–488
Echeverry MB, Salgado ML, Ferreira FR, da-Silva CA, Del Bel EA (2007) Intracerebroventricular administration of nitric oxide-sensitive guanylyl cyclase inhibitors induces catalepsy in mice. Psychopharmacology 194(2):271–278
Finkelstein DI, Stanic D, Parish CL, Tomas D, Dickson K, Horne MK (2000) Axonal sprouting following lesions of the rat substantia nigra. Neuroscience 97(1):99–112
Gomes MZ, Raisman-Vozari R, Del Bel EA (2008) A nitric oxide synthase inhibitor decreases 6-hydroxydopamine effects on tyrosine hydroxylase and neuronal nitric oxide synthase in the rat nigrostriatal pathway. Brain Res 1203:160–169
Guevara-Guzman R, Emson PC, Kendrick KM (1994) Modulation of in vivo striatal transmitter release by nitric oxide and cyclic GMP. J Neurochem 62(2):807–810
Handy RL, Moore PK (1997) Mechanism of the inhibition of neuronal nitric oxide synthase by 1-(2-trifluoromethylphenyl) imidazole (TRIM). Life Sci 60(25):PL389–PL394
Hefti F, Enz A, Melamed E (1985) Partial lesions of the nigrostriatal pathway in the rat. Acceleration of transmitter synthesis and release of surviving dopaminergic neurones by drugs. Neuropharmacology 24(1):19–23
Hornykiewicz O (1993) Parkinson’s disease and the adaptive capacity of the nigrostriatal dopamine system: possible neurochemical mechanisms. Adv Neurol 60:140–147
Hornykiewicz O (1998) Biochemical aspects of Parkinson’s disease. Neurology 51(2 Suppl 2):S2–S9
Huot P, Johnston TH, Koprich JB, Fox SH, Brotchie JM (2013) The pharmacology of l-DOPA-induced dyskinesia in Parkinson’s disease. Pharmacol Rev 65:171–222
Imam SZ, Islam F, Itzhak Y, Slikker W Jr, Ali SF (2000) Prevention of dopaminergic neurotoxicity by targeting nitric oxide and peroxynitrite: implications for the prevention of methamphetamine-induced neurotoxic damage. Ann N Y Acad Sci 914:157–171
Iravani MM, Jenner P (2011) Mechanisms underlying the onset and expression of levodopa-induced dyskinesia and their pharmacological manipulation. J Neural Transm 118(12):1661–1690
Iravani MM, Stockwell KA, Tayarani-Binazir K, Jackson MJ, Smith LA (2008) Inhibition of neuronal nitric oxide synthase as a novel target for suppression of levoda-induced dyskinesia in primates. Neuroscience Meeting Planner Soc. Neurosc. Abstr. 139.15/M6
Iravani MM, McCreary AC, Jenner P (2012) Striatal plasticity in Parkinson’s disease and l-DOPA induced dyskinesia. Parkinsonism Relat Disord 1:S123–S125
Jenner P (2008) Molecular mechanisms of l-DOPA-induced dyskinesia. Nat Rev Neurosci 9(9):665–677
Jonkers N, Sarre S, Ebinger G, Michotte Y (2001) Benserazide decreases central AADC activity, extracellular dopamine levels and levodopa decarboxylation in striatum of the rat. J Neural Transm 108(5):559–570
Keller RW, Kuhr WG, Wightman RM, Zigmond MJ (1988) The effect of l-dopa on in vivo dopamine release from nigrostriatal bundle neurons. Brain Res 447(1):191–194
Lee CS, Cenci MA, Schulzer M, Björklund A (2000) Embryonic ventral mesencephalic grafts improve levodopa-induced dyskinesia in a rat model of Parkinson’s disease. Brain. 123(Pt 7):1365–1379
Lee J, Zhu WM, Stanic D, Finkelstein DI, Horne MH, Henderson J, Lawrence AJ, O’Connor L, Tomas D, Drago J, Horne MK (2008) Sprouting of dopamine terminals and altered dopamine release and uptake in Parkinsonian dyskinesia. Brain 131(Pt 6):1574–1587
Lieu CA, Subramanian T (2012) The interhemispheric connections of the striatum: implications for Parkinson’s disease and drug-induced dyskinesias. Brain Res Bull 87(1):1–9
Lieu CA, Deogaonkar M, Bakay RA, Subramanian T (2011) Dyskinesias do not develop after chronic intermittent levodopa therapy in clinically hemiparkinsonian rhesus monkeys. Parkinsonism Relat Disord 17(1):34–39
Lindgreen HS, Andersson DR, Lagerkvist S, Nissbrandt H, Cenci MA (2010) l-DOPA-induced dopamine efflux in the striatum and the substantia nigra in a rat model of Parkinson’s disease: temporal and quantitative relationship to the expression of dyskinesia. J Neurochem 112:1465–1476
Lundblad M, Andersson M, Winkler C, Kirik D, Wierup N, Cenci MA (2002) Pharmacological validation of behavioural measures of akinesia and dyskinesia in a rat model of Parkinson’s disease. Eur J Neurosci 15(1):120–132
Marin C, Rodriguez-Oroz MC, Obeso JA (2006) Motor complications in Parkinson’s disease and the clinical significance of rotational behavior in the rat: have we wasted our time? Exp Neurol 197:269–274
Meissner W, Ravenscroft P, Reese R, Harnack D, Morgenstern R, Kupsch A, Klitgaard H, Bioulac B, Gross CE, Bezard E, Boraud T (2006) Increased slow oscillatory activity in substantia nigra pars reticulata triggers abnormal involuntary movements in the 6-OHDA-lesioned rat in the presence of excessive extracellular striatal dopamine. Neurobiol Dis 22(3):586–598
Miller DW, Abercrombie ED (1999) Role of high-affinity dopamine uptake and impulse activity in the appearance of extracellular dopamine in striatum after administration of exogenous l-DOPA: studies in intact and 6-hydroxydopamine-treated rats. J Neurochem 72(4):1516–1522
Mishra RK, Gardner EL, Katzman R, Makman MH (1974) Enhancement of dopamine-stimulated adenylate cyclase activity in rat caudate after lesions in substantia nigra: evidence for denervation supersensitivity. Proc Natl Acad Sci USA 71(10):3883–3887
Moore PK, Babbedge RC, Wallace P, Gaffen ZA, Hart SL (1993) 7-Nitroindazole, an inhibitor of nitric oxide synthase, exhibits anti-nociceptive activity in the mouse without increasing blood pressure. Br J Pharmacol 108(2):296–297
Novaretti N, Padovan-Neto FE, Tumas V, da Silva CA, Del Bel EA (2010) Lack of tolerance for the anti-dyskinetic effects of 7-nitroindazole, a neuronal nitric oxide synthase inhibitor, in rats. Braz J Med Biol Res 43(11):1047–1053
Obeso JA, Rodriguez-Oroz MC, Lanciego JL, Rodriguez Diaz M (2004) How does Parkinson’s disease begin? The role of compensatory mechanisms. Trends Neurosci 27(3):125–127
Ogawa N, Tanaka K, Asanuma M (2000) Bromocriptine markedly suppresses levodopa-induced abnormal increase of dopamine turnover in the parkinsonian striatum. Neurochem Res 25(6):755–758
Onn SP, Berger TW, Stricker EM, Zigmond MJ (1986) Effects of intraventricular 6-hydroxydopamine on the dopaminergic innervation of striatum: histochemical and neurochemical analysis. Brain Res 376(1):8–19
Orosz D, Bennett JP (1992) Simultaneous microdialysis in striatum and substantia nigra suggests that the nigra is a major site of action of l-dihydroxyphenylalanine in the “hemiparkinsonian” rat. Exp Neurol 115(3):388–393
Padovan-Neto FE, Echeverry MB, Tumas V, Del-Bel EA (2009) Nitric oxide synthase inhibition attenuates l-DOPA-induced dyskinesias in a rodent model of Parkinson’s disease. Neuroscience 159(3):927–935
Padovan-Neto FE, Echeverry MB, Chiavegatto S, Del-Bel E (2011) Nitric oxide synthase inhibitor improves de novo and long-term l-DOPA-induced dyskinesia in hemiparkinsonian rats. Front Syst Neurosci 5:40
Padovan-Neto FE, Ferreira NR, Tavares D, de Aguiar D, da Silva CA, Raisman-Vozari R, Del Bel E (2013) Anti-dyskinetic effect of the neuronal nitric oxide synthase inhibitor is linked to decrease of FosB/delta-FosB expression. Neurosc Lett 541:126–131
Pavese N, Evans AH, Tai YF, Hotton G, Brooks DJ, Lees AJ, Piccini P (2006) Clinical correlates of levodopa-induced dopamine release in Parkinson disease: a PET study. Neurology 67(9):1612–1617
Pavón N, Martín AB, Mendialdua A, Moratalla R (2006) ERK phosphorylation and FosB expression are associated with l-DOPA-induced dyskinesia in hemiparkinsonian mice. Biol Psychiatry 59:64–74
Paxinos G, Watson W (1998) The rat brain in stereotaxic coordinates. Academic Press, San Diego
Pierucci M, Galati S, Valentino M, Di Matteo V, Benigno A (2011) Nitric oxide modulation of the Basal Ganglia circuitry: therapeutic implication for Parkinson’s disease and other motor disorders. CNS Neurol Disord 10(7):777–791
Pifl C, Hornykiewicz O (2006) Dopamine turnover is upregulated in the caudate/putamen of asymptomatic MPTP-treated rhesus monkeys. Neurochem Int 49(5):519–524
Pritzel M, Huston JP, Sarter M (1983) Behavioral and neuronal reorganization after unilateral substantia nigra lesions: evidence for increased interhemispheric nigrostriatal projections. Neuroscience 9(4):879–888
Rajput AH, Fenton ME, Di Paolo T, Sitte H, Pifl C, Hornykiewicz O (2004) Human brain dopamine metabolism in levodopa-induced dyskinesia and wearing-off. Parkinsonism Relat Disord 10(4):221–226
Roffler-Tarlov S, Sharman DF, Tegerdine P (1971) 3,4-Dihydroxyphenylacetic acid and 4-hydroxy-3-methoxyphenylacetic acid in the mouse striatum: a reflection of intra- and extra-neuronal metabolism of dopamine? Br J Pharmacol 42(3):343–351
Sanchez JJ, Abreu P, Gonzalez MC (2002) Sodium nitroprusside stimulates l-DOPA release from striatal tissue through nitric oxide and cGMP. Eur J Pharmacol 438(1–2):79–83
Silva MT, Rose S, Hindmarsh JG, Aislaitner G, Gorrod JW, Moore PK, Jenner P, Marsden CD (1995) Increased striatal dopamine efflux in vivo following inhibition of cerebral nitric oxide synthase by the novel monosodium salt of 7-nitroindazole. Br J Pharmacol 114(2):257–258
Silva MT, Rose S, Hindmarsh JG, Jenner P (2003) Inhibition of neuronal nitric oxide synthase increases dopamine efflux from rat striatum. J Neural Transm 110(4):353–362
Simola N, Morelli M, Carta AR (2007) The 6-hydroxydopamine model of Parkinson’s disease. Neurotox Res 11(3–4):151–167
Soares-da-Silva P, Garrett MC (1990) A kinetic study of the rate of formation of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the brain of the rat: implications for the origin of DOPAC. Neuropharmacology 29(10):869–874
Southan GJ, Szabó C (1996) Selective pharmacological inhibition of distinct nitric oxide synthase isoforms. Biochem Pharmacol 51(4):383–394
Spadas I, Darmopil S, Vergaño-Vera E, Ortiz O, Oliva I, Vicario-Abejón C, Martín ED, Moratalla R (2012) l-DOPA-induced increase in TH-immunoreactive striatal neurons in Parkinsonian mice: insights into regulation and function. Neurobiol Dis 48(3):271–281
Staunton DA, Wolfe BB, Groves PM, Molinoff PB (1981) Dopamine receptor changes following destruction of the nigrostriatal pathway: lack of a relationship to rotational behavior. Brain Res 211(2):315–327
Storch A, Wolz M, Beuthien-Baumann B, Löhle M, Herting B, Schwanebeck U, Oehme L, van den Hoff J, Perick M, Grählert X, Kotzerke J, Reichmann H (2013) Effects of dopaminergic treatment on striatal dopamine turnover in de novo Parkinson disease. Neurology 80(19):1754–1761
Szawka RE, Ribeiro AB, Leite CM, Helena CV, Franci CR, Anderson GM, Hoffman GE, Anselmo-Franci JA (2010) Kisspeptin regulates prolactin release through hypothalamic dopaminergic neurons. Endocrinology 151(7):3247–3257
Takuma K, Tanaka T, Takahashi T, Hiramatsu N, Ota Y, Ago Y, Matsuda T (2012) Neuronal nitric oxide synthase inhibition attenuates the development of l-DOPA-induced dyskinesia in hemi-Parkinsonian rats. Eur J Pharmacol 683(1–3):166–173
Thomas B, Saravanan KS, Mohanakumar KP (2008) In vitro and in vivo evidences that antioxidant action contributes to the neuroprotective effects of the neuronal nitric oxide synthase and monoamine oxidase-B inhibitor, 7-NI. Neurochem Int 52(6):990–1001
West AR, Galloway MP (1997) Endogenous nitric oxide facilitates striatal dopamine and glutamate efflux in vivo: role of ionotropic glutamate receptor-dependent mechanisms. Neuropharmacology 36(11–12):1571–1581
West AR, Galloway MP, Grace AA (2002) Regulation of striatal dopamine neurotransmission by nitric oxide: effector pathways and signaling mechanisms. Synapse 44(4):227–245
Westerink BH (1985) Sequence and significance of dopamine metabolism in the rat brain. Neurochem Int 7(2):221–227
Wolf ME, Zigmond MJ, Kapatos G (1998) Tyrosine hydroxylase content of residual striatal dopamine nerve terminals following 6-hydroxydopamine administration: a flow cytometric study. J Neurochem 53(3):879–885
Xu ZC, Ling G, Sahr RN, Neal-Beliveau BS (2005) Asymmetrical changes of dopamine receptors in the striatum after unilateral dopamine depletion. Brain Res 1038(2):163–170
Yang J, Sadler TR, Givrad TK, Maarek JM, Holschneider DP (2007) Changes in brain functional activation during resting and locomotor states after unilateral nigrostriatal damage in rats. Neuroimage 36(3):755–773
Youdim MB, Edmondson D, Tipton KF (2006) The therapeutic potential of monoamine oxidase inhibitors. Nat Rev Neurosci 7(4):295–309
Yuste JE, Bermúdez M, Bernal FR, Barcia C, Martin J, Del Bel E, Villalba EF, Herrero MT (2011) NOS inhibitors improve l-DOPA-induced dyskinesias in experimental models of Parkinsonism. Mov Disord 26(Suppl2):S257–S258
Zetterström T, Herrera-Marschitz M, Ungerstedt U (1986) Simultaneous measurement of dopamine release and rotational behaviour in 6-OHDA denervated rats using intracerebral dialysis. Brain Res 376(1):1–7
Zigmond MJ, Acheson AL, Stachowiak MK, Stricker EM (1984) Neurochemical compensation after nigrostriatal bundle injury in an animal model of preclinical Parkinsonism. Arch Neurol 41(8):856–861
Zigmond MJ, Abercrombie ED, Stricker EM (1990a) Partial damage to nigrostriatal bundle: compensatory changes and the action of l-dopa. J Neural Transm 29:217–232
Zigmond MJ, Abercrombie ED, Berger TW, Grace AA, Stricker EM (1990b) Compensations after lesions of central dopaminergic neurons: some clinical and basic implications. Trends Neurosci 13(7):290–296
Zigmond MJ, Hastings TG, Perez RG (2002) Increased dopamine turnover after partial loss of dopaminergic neurons: compensation or toxicity? Parkinsonism Relat Disord 8(6):389–393
Acknowledgments
The authors are most obliged to Danielle de Oliveira Tavares and Aline Luciana Tolentino for the excellent photomicrography and help with histological analyses. We also acknowledge grants from FAPESP-Projeto Temático 2012, FAPESP-INSERM, CAPES-COFECUB, CNPQ, and CNPQ-Science without Border project. FAPESP supported Fernando E. Padovan-Neto with a PhD fellowship. Aline Luciana Tolentino and Angélica C. Romano-Dutra were CNPQ-PIBIC fellowship holders. E.A.Del-Bel is a Senior Research from CNPq.
Conflict of interest
We declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Del-Bel, E., Padovan-Neto, F.E., Szawka, R.E. et al. Counteraction by Nitric Oxide Synthase Inhibitor of Neurochemical Alterations of Dopaminergic System in 6-OHDA-Lesioned Rats Under l-DOPA Treatment. Neurotox Res 25, 33–44 (2014). https://doi.org/10.1007/s12640-013-9406-3
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12640-013-9406-3