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Age-dependent alterations in key components of the nigrostriatal dopaminergic system and distinct motor phenotypes. Acta Pharmacol Sin 2022; 43:862-875. [PMID: 34244603 PMCID: PMC8975991 DOI: 10.1038/s41401-021-00713-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 06/06/2021] [Indexed: 02/06/2023] Open
Abstract
The nigrostriatal dopaminergic (DA) system, which includes DA neurons in the ventral and dorsal tiers of the substantia nigra pars compacta (vSNc, dSNc) and DA terminals in the dorsal striatum, is critically implicated in motor control. Accumulating studies demonstrate that both the nigrostriatal DA system and motor function are impaired in aged subjects. However, it is unknown whether dSNc and vSNc DA neurons and striatal DA terminals age in similar patterns, and whether these changes parallel motor deficits. To address this, we performed ex vivo patch-clamp recordings in dSNc and vSNc DA neurons, measured striatal dopamine release, and analyzed motor behaviors in rodents. Spontaneous firing in dSNc and vSNc DA neurons and depolarization-evoked firing in dSNc DA neurons showed inverse V-shaped changes with age. But depolarization-evoked firing in vSNc DA neurons increased with age. In the dorsal striatum, dopamine release declined with age. In locomotor tests, 12-month-old rodents showed hyperactive exploration, relative to 6- and 24-month-old rodents. Additionally, aged rodents showed significant deficits in coordination. Elevating dopamine levels with a dopamine transporter inhibitor improved both locomotion and coordination. Therefore, key components in the nigrostriatal DA system exhibit distinct aging patterns and may contribute to age-related alterations in locomotion and coordination.
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Carving the senescent phenotype by the chemical reactivity of catecholamines: An integrative review. Ageing Res Rev 2022; 75:101570. [PMID: 35051644 DOI: 10.1016/j.arr.2022.101570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/11/2022] [Accepted: 01/15/2022] [Indexed: 11/21/2022]
Abstract
Macromolecules damaged by covalent modifications produced by chemically reactive metabolites accumulate in the slowly renewable components of living bodies and compromise their functions. Among such metabolites, catecholamines (CA) are unique, compared with the ubiquitous oxygen, ROS, glucose and methylglyoxal, in that their high chemical reactivity is confined to a limited set of cell types, including the dopaminergic and noradrenergic neurons and their direct targets, which suffer from CA propensities for autoxidation yielding toxic quinones, and for Pictet-Spengler reactions with carbonyl-containing compounds, which yield mitochondrial toxins. The functions progressively compromised because of that include motor performance, cognition, reward-driven behaviors, emotional tuning, and the neuroendocrine control of reproduction. The phenotypic manifestations of the resulting disorders culminate in such conditions as Parkinson's and Alzheimer's diseases, hypertension, sarcopenia, and menopause. The reasons to suspect that CA play some special role in aging accumulated since early 1970-ies. Published reviews address the role of CA hazardousness in the development of specific aging-associated diseases. The present integrative review explores how the bizarre discrepancy between CA hazardousness and biological importance could have emerged in evolution, how much does the chemical reactivity of CA contribute to the senescent phenotype in mammals, and what can be done with it.
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Demonstration of prion-like properties of mutant huntingtin fibrils in both in vitro and in vivo paradigms. Acta Neuropathol 2019; 137:981-1001. [PMID: 30788585 PMCID: PMC6531424 DOI: 10.1007/s00401-019-01973-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/07/2019] [Accepted: 02/07/2019] [Indexed: 12/02/2022]
Abstract
In recent years, evidence has accumulated to suggest that mutant huntingtin protein (mHTT) can spread into healthy tissue in a prion-like fashion. This theory, however, remains controversial. To fully address this concept and to understand the possible consequences of mHTT spreading to Huntington’s disease pathology, we investigated the effects of exogenous human fibrillar mHTT (Q48) and huntingtin (HTT) (Q25) N-terminal fragments in three cellular models and three distinct animal paradigms. For in vitro experiments, human neuronal cells [induced pluripotent stem cell-derived GABA neurons (iGABA) and (SH-SY5Y)] as well as human THP1-derived macrophages, were incubated with recombinant mHTT fibrils. Recombinant mHTT and HTT fibrils were taken up by all cell types, inducing cell morphology changes and death. Variations in HTT aggregation were further observed following incubation with fibrils in both THP1 and SH-SY5Y cells. For in vivo experiments, adult wild-type (WT) mice received a unilateral intracerebral cortical injection and R6/2 and WT pups were administered fibrils via bilateral intraventricular injections. In both protocols, the injection of Q48 fibrils resulted in cognitive deficits and increased anxiety-like behavior. Post-mortem analysis of adult WT mice indicated that most fibrils had been degraded/cleared from the brain by 14 months post-surgery. Despite the absence of fibrils at these later time points, a change in the staining pattern of endogenous HTT was detected. A similar change was revealed in post-mortem analysis of the R6/2 mice. These effects were specific to central administration of fibrils, as mice receiving intravenous injections were not characterized by behavioral changes. In fact, peripheral administration resulted in an immune response mounting against the fibrils. Together, the in vitro and in vivo data indicate that exogenously administered mHTT is capable of both causing and exacerbating disease pathology.
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Salvatore MF, McInnis TR, Cantu MA, Apple DM, Pruett BS. Tyrosine Hydroxylase Inhibition in Substantia Nigra Decreases Movement Frequency. Mol Neurobiol 2018; 56:2728-2740. [PMID: 30056575 DOI: 10.1007/s12035-018-1256-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 07/17/2018] [Indexed: 10/28/2022]
Abstract
Reduced movement frequency or physical activity (bradykinesia) occurs with high prevalence in the elderly. However, loss of striatal tyrosine hydroxylase (TH) in aging humans, non-human primates, or rodents does not reach the ~ 80% loss threshold associated with bradykinesia onset in Parkinson's disease. Moderate striatal dopamine (DA) loss, either following TH inhibition or decreased TH expression, may not affect movement frequency. In contrast, moderate DA or TH loss in the substantia nigra (SN), as occurs in aging, is of similar magnitude (~ 40%) to nigral TH loss at bradykinesia onset in Parkinson's disease. In aged rats, increased TH expression and DA in SN alone increases movement frequency, suggesting aging-related TH and DA loss in the SN contributes to aging-related bradykinesia or decreased physical activity. To test this hypothesis, the SN was targeted with bilateral guide cannula in young (6 months old) rats, in a within-subjects design, to evaluate the impact of nigral TH inhibition on movement frequency and speed. The TH inhibitor, α-methyl-p-tyrosine (AMPT) reduced nigral DA (~ 40%) 45-150 min following infusion, without affecting DA in striatum, nucleus accumbens, or adjacent ventral tegmental area. Locomotor activity in the open-field was recorded up to 3 h following nigral saline or AMPT infusion in each test subject. During the period of nigra-specific DA reduction, movement frequency, but not movement speed, was significantly decreased. These results indicate that DA or TH loss in the SN, as observed in aging, contributes as a central mechanism of reduced movement frequency.
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Affiliation(s)
- Michael F Salvatore
- Institute for Healthy Aging and Center for Neuroscience Discovery, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX, 76107, USA.
| | - Tamara R McInnis
- Institute for Healthy Aging and Center for Neuroscience Discovery, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX, 76107, USA
| | - Mark A Cantu
- Institute for Healthy Aging and Center for Neuroscience Discovery, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX, 76107, USA
| | - Deana M Apple
- Department of Cell Systems and Anatomy, Barshop Institute for Aging and Longevity Studies, UT Health San Antonio, San Antonio, TX, 78229, USA
| | - Brandon S Pruett
- Department of Psychiatry and Human Behavior, Warren Alpert Medical School of Brown University, Providence, RI, 02912, USA.,Department of Pharmacology, Toxicology, & Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA, 71130, USA
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Thanos PK, Hamilton J, O'Rourke JR, Napoli A, Febo M, Volkow ND, Blum K, Gold M. Dopamine D2 gene expression interacts with environmental enrichment to impact lifespan and behavior. Oncotarget 2017; 7:19111-23. [PMID: 26992232 PMCID: PMC4991369 DOI: 10.18632/oncotarget.8088] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 02/23/2016] [Indexed: 12/22/2022] Open
Abstract
Aging produces cellular, molecular, and behavioral changes affecting many areas of the brain. The dopamine (DA) system is known to be vulnerable to the effects of aging, which regulate behavioral functions such as locomotor activity, body weight, and reward and cognition. In particular, age-related DA D2 receptor (D2R) changes have been of particular interest given its relationship with addiction and other rewarding behavioral properties. Male and female wild-type (Drd2 +/+), heterozygous (Drd2 +/−) and knockout (Drd2 −/−) mice were reared post-weaning in either an enriched environment (EE) or a deprived environment (DE). Over the course of their lifespan, body weight and locomotor activity was assessed. While an EE was generally found to be correlated with longer lifespan, these increases were only found in mice with normal or decreased expression of the D2 gene. Drd2 +/+ EE mice lived nearly 16% longer than their DE counterparts. Drd2 +/+ and Drd2 +/− EE mice lived 22% and 21% longer than Drd2 −/− EE mice, respectively. Moreover, both body weight and locomotor activity were moderated by environmental factors. In addition, EE mice show greater behavioral variability between genotypes compared to DE mice with respect to body weight and locomotor activity.
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Affiliation(s)
- Panayotis K Thanos
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Research Institute on Addictions, University at Buffalo, Buffalo, NY, USA
| | - John Hamilton
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Research Institute on Addictions, University at Buffalo, Buffalo, NY, USA
| | - Joseph R O'Rourke
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Research Institute on Addictions, University at Buffalo, Buffalo, NY, USA
| | - Anthony Napoli
- Department of Psychology, Suffolk Community College, Riverhead, NY, USA
| | - Marcelo Febo
- Department of Psychiatry, University of Florida, Gainesville, FL, USA
| | | | - Kenneth Blum
- Department of Psychiatry, University of Florida, Gainesville, FL, USA
| | - Mark Gold
- Department of Psychiatry, University of Florida, Gainesville, FL, USA
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Resveratrol and pinostilbene confer neuroprotection against aging-related deficits through an ERK1/2-dependent mechanism. J Nutr Biochem 2017; 54:77-86. [PMID: 29268122 DOI: 10.1016/j.jnutbio.2017.10.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 09/18/2017] [Accepted: 10/24/2017] [Indexed: 01/02/2023]
Abstract
Age-related declines in motor function may be due, in part, to an increase in oxidative stress in the aging brain leading to dopamine (DA) neuronal cell death. In this study, we examined the neuroprotective effects of natural antioxidants resveratrol and pinostilbene against age-related DAergic cell death and motor dysfunction using SH-SY5Y neuroblastoma cells and young, middle-aged, and old male C57BL/6 mice. Resveratrol and pinostilbene protected SH-SY5Y cells from a DA-induced decrease in cell viability. Dietary supplementation with resveratrol and pinostilbene inhibited the decline of motor function observed with age. While DA and its metabolites (DOPAC and HVA), dopamine transporter, and tyrosine hydroxylase levels remain unchanged during aging or treatment, resveratrol and pinostilbene increased ERK1/2 activation in vitro and in vivo in an age-dependent manner. Inhibition of ERK1/2 in SH-SY5Y cells decreased the protective effects of both compounds. These data suggest that resveratrol and pinostilbene alleviate age-related motor decline via the promotion of DA neuronal survival and activation of the ERK1/2 pathways.
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Rose KM, Parmar MS, Cavanaugh JE. Dietary supplementation with resveratrol protects against striatal dopaminergic deficits produced by in utero LPS exposure. Brain Res 2014; 1573:37-43. [DOI: 10.1016/j.brainres.2014.05.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 05/14/2014] [Accepted: 05/16/2014] [Indexed: 01/08/2023]
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Bussi IL, Levín G, Golombek DA, Agostino PV. Involvement of dopamine signaling in the circadian modulation of interval timing. Eur J Neurosci 2014; 40:2299-310. [PMID: 24689904 DOI: 10.1111/ejn.12569] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 02/12/2014] [Accepted: 02/21/2014] [Indexed: 02/03/2023]
Abstract
Duration discrimination within the seconds-to-minutes range, known as interval timing, involves the interaction of cortico-striatal circuits via dopaminergic-glutamatergic pathways. Besides interval timing, most (if not all) organisms exhibit circadian rhythms in physiological, metabolic and behavioral functions with periods close to 24 h. We have previously reported that both circadian disruption and desynchronization impaired interval timing in mice. In this work we studied the involvement of dopamine (DA) signaling in the interaction between circadian and interval timing. We report that daily injections of levodopa improved timing performance in the peak-interval procedure in C57BL/6 mice with circadian disruptions, suggesting that a daily increase of DA is necessary for an accurate performance in the timing task. Moreover, striatal DA levels measured by reverse-phase high-pressure liquid chromatography indicated a daily rhythm under light/dark conditions. This daily variation was affected by inducing circadian disruption under constant light (LL). We also demonstrated a daily oscillation in tyrosine hydroxylase levels, DA turnover (3,4-dihydroxyphenylacetic acid/DA levels), and both mRNA and protein levels of the circadian component Period2 (Per2) in the striatum and substantia nigra, two brain areas relevant for interval timing. None of these oscillations persisted under LL conditions. We suggest that the lack of DA rhythmicity in the striatum under LL - probably regulated by Per2 - could be responsible for impaired performance in the timing task. Our findings add further support to the notion that circadian and interval timing share some common processes, interacting at the level of the dopaminergic system.
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Affiliation(s)
- Ivana L Bussi
- Laboratorio de Cronobiología, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes/CONICET, R. S. Peña 352, B1876BXD, Bernal, Buenos Aires, Argentina
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Allen EN, Cavanaugh JE. Loss of motor coordination in an aging mouse model. Behav Brain Res 2014; 267:119-25. [PMID: 24675158 DOI: 10.1016/j.bbr.2014.03.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 03/12/2014] [Accepted: 03/17/2014] [Indexed: 12/17/2022]
Abstract
With age, there is an increase in motor deficits that leads to an increased incidence of slips and falls. As the elderly population continues to grow, there is a need for aging models and research that focus on behavioral deficits that occur with normal, non-diseased aging. The present study was designed to examine the appropriateness of C57Bl/6 male mice as aging animal models using the challenging beam and cylinder tests to measure motor coordination and spontaneous activity, respectively. Using young (2-4 mo), middle-aged (10-12 mo), and aged (22-24 mo) mice, we observed that aged C57Bl/6 male mice make more errors on the challenging beam task and take fewer hind limb steps as compared to young and middle-aged mice. Body weight and food intake were also measured to determine if these parameters were confounding factors in the interpretation of the behavioral data. Increases in body weight and food consumption were not observed in the oldest group that made the most errors. Together these data indicate that aged C57BL/6 mice display age-related motor deficits similar to those seen in humans and are an appropriate model of motor deficits that occur with age.
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Affiliation(s)
- Erika N Allen
- Division of Pharmaceutical Sciences, Mylan School of Pharmacy, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282, United States
| | - Jane E Cavanaugh
- Division of Pharmaceutical Sciences, Mylan School of Pharmacy, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282, United States.
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Parmar MS, Jaumotte JD, Wyrostek SL, Zigmond MJ, Cavanaugh JE. Role of ERK1, 2, and 5 in dopamine neuron survival during aging. Neurobiol Aging 2013; 35:669-79. [PMID: 24411019 DOI: 10.1016/j.neurobiolaging.2013.09.031] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 07/15/2013] [Accepted: 09/19/2013] [Indexed: 11/27/2022]
Abstract
Extracellular signal-regulated kinases (ERKs) 1, 2, and 5 have been shown to play distinct roles in proliferation, differentiation, and neuronal viability. In this study, we examined ERK1, 2, and 5 expression and activation in the substantia nigra (SN), striatum (STR), and ventral tegmental area (VTA) during aging. An age-related decrease in phosphorylated ERK5 was observed in the SN and STR, whereas an increase in total ERK1 was observed in all 3 regions. In primary cultures of the SN and VTA, inhibition of ERK5 but not ERK1 and 2 decreased dopamine neuronal viability significantly. These data suggest that ERK5 is essential for the basal survival of SN and VTA dopaminergic neurons. This is the first study to examine ERK1, 2, and 5 expression and activation in the SN, STR, and VTA during aging, and the relative roles of ERK1, 2, and 5 in basal survival of SN and VTA dopaminergic neurons. These data raise the possibility that a decline in ERK5 signaling may play a role in age-related impairments in dopaminergic function.
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Affiliation(s)
- Mayur S Parmar
- Division of Pharmaceutical Sciences, Mylan School of Pharmacy, Duquesne University, Pittsburgh, PA, USA
| | - Juliann D Jaumotte
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA, USA
| | - Stephanie L Wyrostek
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael J Zigmond
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jane E Cavanaugh
- Division of Pharmaceutical Sciences, Mylan School of Pharmacy, Duquesne University, Pittsburgh, PA, USA.
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Dixit A, Srivastava G, Verma D, Mishra M, Singh PK, Prakash O, Singh MP. Minocycline, levodopa and MnTMPyP induced changes in the mitochondrial proteome profile of MPTP and maneb and paraquat mice models of Parkinson's disease. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1227-40. [PMID: 23562983 DOI: 10.1016/j.bbadis.2013.03.019] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 03/25/2013] [Accepted: 03/26/2013] [Indexed: 12/31/2022]
Abstract
Mitochondrial dysfunction is the foremost perpetrator of the nigrostriatal dopaminergic neurodegeneration leading to Parkinson's disease (PD). However, the roles played by majority of the mitochondrial proteins in PD pathogenesis have not yet been deciphered. The present study investigated the effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and combined maneb and paraquat on the mitochondrial proteome of the nigrostriatal tissues in the presence or absence of minocycline, levodopa and manganese (III) tetrakis (1-methyl-4-pyridyl) porphyrin (MnTMPyP). The differentially expressed proteins were identified and proteome profiles were correlated with the pathological and biochemical anomalies induced by MPTP and maneb and paraquat. MPTP altered the expression of twelve while combined maneb and paraquat altered the expression of fourteen proteins. Minocycline, levodopa and MnTMPyP, respectively, restored the expression of three, seven and eight proteins in MPTP and seven, eight and eight proteins in maneb- and paraquat-treated groups. Although levodopa and MnTMPyP rescued from MPTP- and maneb- and paraquat-mediated increase in the microglial activation and decrease in manganese-superoxide dismutase expression and complex I activity, dopamine content and number of dopaminergic neurons, minocycline defended mainly against maneb- and paraquat-mediated alterations. The results demonstrate that MPTP and combined maneb and paraquat induce mitochondrial dysfunction and microglial activation and alter the expression of a bunch of mitochondrial proteins leading to the nigrostriatal dopaminergic neurodegeneration and minocycline, levodopa or MnTMPyP variably offset scores of such changes.
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Affiliation(s)
- Anubhuti Dixit
- CSIR-Indian Institute of Toxicology Research CSIR-IITR, M. G. Marg, Post Box-80, Lucknow-226 001, UP, India
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Ionov ID, Severtsev NN. Histamine- and haloperidol-induced catalepsy in aged mice: differential responsiveness to L-DOPA. Psychopharmacology (Berl) 2012; 223:191-7. [PMID: 22526536 DOI: 10.1007/s00213-012-2706-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 03/26/2012] [Indexed: 11/27/2022]
Abstract
RATIONALE In rodents and dog, histamine induces catalepsy, a dopamine-dependent phenomenon that resembles the extrapyramidal signs of Parkinson's disease (PD). Histamine was also found to damage the dopaminergic neurons in rat substantia nigra. These facts, as well as an increase in brain histamine levels in Parkinsonian patients, suggest a pathogenic role for histamine in PD. As it seems, a comparison between pattern of experimental brain histamine toxicity and signs of PD would elucidate the role of histamine in PD pathogenesis. OBJECTIVE This study aimed to examine whether mouse histamine-induced catalepsy shares such age-related traits of PD as disease aggravation and underresponsiveness to 3,4-dihydroxy-L: -phenylalanine (L: -DOPA) in aged patients. For comparison purposes, haloperidol-induced catalepsy was studied. METHODS The intensity of catalepsy was measured as the time the mouse maintained an abnormal posture. The cataleptogens, histamine or haloperidol, were administered intracerebroventricularly and subcutaneously, respectively. RESULTS The cataleptogenic activity of histamine was significantly higher in 18-19-month-old and 22-23-month-old mice than 3-4-month-old ones. Aging was found to decrease the responsiveness of the histamine-induced catalepsy to L: -DOPA. The intensity of the haloperidol-induced catalepsy and its sensitivity to L: -DOPA were found independent of the animal's age. CONCLUSIONS The mouse histamine-induced catalepsy, unlike haloperidol-induced one, displays the same pattern of age dependency as PD. These findings support an involvement of histamine in the PD pathogenesis.
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Affiliation(s)
- Ilya D Ionov
- Centre on Theoretical Problems in Physical and Chemical Pharmacology, Russian Academy of Sciences, Leninsky Prospect 123-4-63, Moscow 117513, Russia.
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