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Taherian N, Vaezi G, Neamati A, Hojjati V, Ghorbani-Taherdehi F, Sahebkar A, Gorji-Valokola M. The dose-dependent neuroprotective effect of norepinephrine in improving memory retrieval in an experimental model of multiple sclerosis, experimental autoimmune encephalomyelitis. Brain Res Bull 2024; 209:110907. [PMID: 38395110 DOI: 10.1016/j.brainresbull.2024.110907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/26/2024] [Accepted: 02/20/2024] [Indexed: 02/25/2024]
Abstract
Multiple sclerosis (MS) is considered an immune-mediated inflammatory disorder that causes cognitive impairments by damaging the hippocampal tissue. Conversely, norepinephrine (NEP) has anti-inflammatory and re-myelinating properties, which improve cognitive impairments. The aim of this study was to assess the neuroprotective effects of NEP on learning and memory disorders in an experimental animal model of MS. Two guide cannulas were bilaterally implanted in the rat hippocampal CA1 regions. After recovery, the animals received 3 μl of 0.01% ethidium bromide (EtB) in each of both hippocampal regions. After three days, the rats were randomly divided into 6 groups (8 rats/group), including control, sham 1, sham 2, and three groups of NEP 0.25, 0.5, and 1 mg/kg by intrahippocampal injection. Behavioral tests (e.g. shuttle box test and open-field test) were then performed. Finally, ROS, MDA, GSH, TNF-α, IL-6, and IL-1β concentrations in the left CA1 area, as well as using western-blot analysis, p-p38, p-JNK, p-AKT, p-ERK1/2, p-NMDA, p-AMPA, p-CREB, and BDNF proteins in the right CA1 region evaluated. The EtB injection increased ROS, MDA, TNF-α, IL-6, and IL-1β levels, as well as p-JNK and p-P38, except all other proteins, while decreasing GSH content, as well as step-through latency and locomotor activity in sham groups compared to the control group. Conversely, NEP (0.5 and 1 mg/kg, particularly at the dose of 1 mg/kg) counterbalanced all the alterations mentioned above in comparison to the sham groups. The EtB induced learning and memory impairment; however, NEP dose-dependently restored these impairments to normal levels.
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Affiliation(s)
- Narjes Taherian
- Department of Biology, Damghan Branch, Islamic Azad University, Damghan, Iran
| | - Gholamhassan Vaezi
- Department of Biology, Damghan Branch, Islamic Azad University, Damghan, Iran
| | - Ali Neamati
- Department of Biology, Mashhad Branch, Islamic Azad University, Mashhad, Iran
| | - Vida Hojjati
- Department of Biology, Damghan Branch, Islamic Azad University, Damghan, Iran
| | - Faezeh Ghorbani-Taherdehi
- Department of Anatomy and Cell Biology, School of Medicine, Esfahan University of Medical Sciences, Esfahan, Iran
| | - Amirhossein Sahebkar
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mahmoud Gorji-Valokola
- Department of Food and Drug Administration, Shahid Sadoughi University of Medical Sciences, Yazd, Iran; Department of Pharmacology, Brain and Spinal Injury Repair Research Center, Tehran University of Medical Science, Tehran, Iran.
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Herpes Simplex Virus Type 1 Preferentially Enhances Neuro-Inflammation and Senescence in Brainstem of Female Mice. J Virol 2022; 96:e0108122. [PMID: 35975996 PMCID: PMC9472638 DOI: 10.1128/jvi.01081-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Following acute infection, herpes simplex virus 1 (HSV-1) establishes lifelong latency in neurons. The latency associated transcript (LAT) is the only viral gene abundantly expressed during latency. Wild-type (WT) HSV-1 reactivates more efficiently than LAT mutants because LAT promotes establishment and maintenance of latency. While sensory neurons in trigeminal ganglia (TG) are important sites for latency, brainstem is also a site for latency and reactivation from latency. The principal sensory nucleus of the spinal trigeminal tract (Pr5) likely harbors latent HSV-1 because it receives afferent inputs from TG. The locus coeruleus (LC), an adjacent brainstem region, sends axonal projections to cortical structures and is indirectly linked to Pr5. Senescent cells accumulate in the nervous system during aging and accelerate neurodegenerative processes. Generally senescent cells undergo irreversible cell cycle arrest and produce inflammatory cytokines and chemokines. Based on these observations, we hypothesized HSV-1 influences senescence and inflammation in Pr5 and LC of latently infected mice. This hypothesis was tested using a mouse model of infection. Strikingly, female but not age-matched male mice latently infected with a LAT null mutant (dLAT2903) exhibited significantly higher levels of senescence markers and inflammation in LC, including cell cycle inhibitor p16, NLRP3 (NOD-, LRR- and pyrin domain-containing protein 3), IL-1α, and IL-β. Conversely, Pr5 in female but not male mice latently infected with WT HSV-1 or dLAT2903 exhibited enhanced expression of important inflammatory markers. The predilection of HSV-1 to induce senescence and inflammation in key brainstem regions of female mice infers that enhanced neurodegeneration occurs. IMPORTANCE HSV-1 (herpes simplex virus 1), an important human pathogen, establishes lifelong latency in neurons in trigeminal ganglia and the central nervous system. In contrast to productive infection, the only viral transcript abundantly expressed in latently infected neurons is the latency associated transcript (LAT). The brainstem, including principal sensory nucleus of the spinal trigeminal tract (Pr5) and locus coeruleus (LC), may expedite HSV-1 spread from trigeminal ganglia to the brain. Enhanced senescence and expression of key inflammatory markers were detected in LC of female mice latently infected with a LAT null mutant (dLAT2903) relative to age-matched male or female mice latently infected with wild-type HSV-1. Conversely, wild-type HSV-1 and dLAT2903 induced higher levels of senescence and inflammatory markers in Pr5 of latently infected female mice. In summary, enhanced inflammation and senescence in LC and Pr5 of female mice latently infected with HSV-1 are predicted to accelerate neurodegeneration.
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Zeng F, Fan Y, Brown RW, Drew Gill W, Price JB, Jones TC, Zhu MY. Effects of Manipulation of Noradrenergic Activities on the Expression of Dopaminergic Phenotypes in Aged Rat Brains. ASN Neuro 2021; 13:17590914211055064. [PMID: 34812056 PMCID: PMC8613899 DOI: 10.1177/17590914211055064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
This study investigated the effects of the pharmacological manipulation of noradrenergic activities on dopaminergic phenotypes in aged rats. Results showed that the administration of L-threo-3,4-dihydroxyphenylserine (L-DOPS) for 21 days significantly increased the expression of tyrosine hydroxylase (TH) and dopamine transporter (DAT) in the striatum and substantia nigra (SN) of 23-month-old rats. Furthermore, this treatment significantly increased norepinephrine/DA concentrations in the striatum and caused a deficit of sensorimotor gating as measured by prepulse inhibition (PPI). Next, old rats were injected with the α2-adrenoceptor antagonist 2-methoxy idazoxan or β2-adrenoceptor agonist salmeterol for 21 days. Both drugs produced similar changes of TH and DAT in the striatum and SN. Moreover, treatments with L-DOPS, 2-methoxy idazoxan, or salmeterol significantly increased the protein levels of phosphorylated Akt in rat striatum and SN. However, although a combination of 2-methoxy idazoxan and salmeterol resulted in a deficit of PPI in these rats, the administration of 2-methoxy idazoxan alone showed an opposite behavioral change. The in vitro experiments revealed that treatments with norepinephrine markedly increased mRNAs and proteins of ATF2 and CBP/p300 and reduced mRNA and proteins of HDAC2 and HDAC5 in MN9D cells. A ChIP assay showed that norepinephrine significantly increased CBP/p300 binding or reduced HDAC2 and HDAC5 binding on the TH promoter. The present results indicate that facilitating noradrenergic activity in the brain can improve the functions of dopaminergic neurons in aged animals. While this improvement may have biochemically therapeutic indication for the status involving the degeneration of dopaminergic neurons, it may not definitely include behavioral improvements, as indicated by using 2-methoxy idazoxan only.
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Affiliation(s)
- Fei Zeng
- Department of Neurology, Renmin Hospital of the Wuhan University, China.,Departments of Biomedical Sciences, Quillen College of Medicine, 4154East Tennessee State University, USA
| | - Yan Fan
- Departments of Biomedical Sciences, Quillen College of Medicine, 4154East Tennessee State University, USA.,Department of Biochemistry, Nantong University College of Medicine, China
| | - Russell W Brown
- Departments of Biomedical Sciences, Quillen College of Medicine, 4154East Tennessee State University, USA
| | - Wesley Drew Gill
- Departments of Biomedical Sciences, Quillen College of Medicine, 4154East Tennessee State University, USA
| | - Jennifer B Price
- Department of Biological Sciences, College of Arts and Sciences, 4154East Tennessee State University, USA
| | - Thomas C Jones
- Department of Biological Sciences, College of Arts and Sciences, 4154East Tennessee State University, USA
| | - Meng-Yang Zhu
- Departments of Biomedical Sciences, Quillen College of Medicine, 4154East Tennessee State University, USA
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Janitzky K. Impaired Phasic Discharge of Locus Coeruleus Neurons Based on Persistent High Tonic Discharge-A New Hypothesis With Potential Implications for Neurodegenerative Diseases. Front Neurol 2020; 11:371. [PMID: 32477246 PMCID: PMC7235306 DOI: 10.3389/fneur.2020.00371] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 04/14/2020] [Indexed: 12/21/2022] Open
Abstract
The locus coeruleus (LC) is a small brainstem nucleus with widely distributed noradrenergic projections to the whole brain, and loss of LC neurons is a prominent feature of age-related neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD). This article discusses the hypothesis that in early stages of neurodegenerative diseases, the discharge mode of LC neurons could be changed to a persistent high tonic discharge, which in turn might impair phasic discharge. Since phasic discharge of LC neurons is required for the release of high amounts of norepinephrine (NE) in the brain to promote anti-inflammatory and neuroprotective effects, persistent high tonic discharge of LC neurons could be a key factor in the progression of neurodegenerative diseases. Transcutaneous vagal stimulation (t-VNS), a non-invasive technique that potentially increases phasic discharge of LC neurons, could therefore provide a non-pharmacological treatment approach in specific disease stages. This article focuses on LC vulnerability in neurodegenerative diseases, discusses the hypothesis that a persistent high tonic discharge of LC neurons might affect neurodegenerative processes, and finally reflects on t-VNS as a potentially useful clinical tool in specific stages of AD and PD.
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Affiliation(s)
- Kathrin Janitzky
- Department of Neurology, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
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Pacholko AG, Wotton CA, Bekar LK. Poor Diet, Stress, and Inactivity Converge to Form a "Perfect Storm" That Drives Alzheimer's Disease Pathogenesis. NEURODEGENER DIS 2019; 19:60-77. [PMID: 31600762 DOI: 10.1159/000503451] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 09/17/2019] [Indexed: 11/19/2022] Open
Abstract
North American incidence of Alzheimer's disease (AD) is expected to more than double over the coming generation. Although genetic factors surrounding the production and clearance of amyloid-β and phosphorylated tau proteins are known to be responsible for a subset of early-onset AD cases, they do not explain the pathogenesis of the far more prevalent sporadic late-onset variant of the disease. It is thus likely that lifestyle and environmental factors contribute to neurodegenerative processes implicated in the pathogenesis of AD. Herein, we review evidence that (1) excess sucrose consumption induces AD-associated liver pathologies and brain insulin resistance, (2) chronic stress overdrives activity of locus coeruleus neurons, leading to loss of function (a common event in neurodegeneration), (3) high-sugar diets and stress promote the loss of neuroprotective sex hormones in men and women, and (4) Western dietary trends set the stage for a lithium-deficient state. We propose that these factors may intersect as part of a "perfect storm" to contribute to the widespread prevalence of neurodegeneration and AD. In addition, we put forth the argument that exercise and supplementation with trace lithium can counteract many of the deleterious consequences associated with excessive caloric intake and perpetual stress. We conclude that lifestyle and environmental factors likely contribute to AD pathogenesis and that simple lifestyle and dietary changes can help counteract their effects.
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Affiliation(s)
- Anthony G Pacholko
- Department of Anatomy, Physiology, and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Caitlin A Wotton
- Department of Anatomy, Physiology, and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Lane K Bekar
- Department of Anatomy, Physiology, and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada,
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Choudhary P, Pacholko AG, Palaschuk J, Bekar LK. The locus coeruleus neurotoxin, DSP4, and/or a high sugar diet induce behavioral and biochemical alterations in wild-type mice consistent with Alzheimers related pathology. Metab Brain Dis 2018; 33:1563-1571. [PMID: 29862455 DOI: 10.1007/s11011-018-0263-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 05/30/2018] [Indexed: 12/28/2022]
Abstract
Alzheimer's disease (AD) is the sixth leading cause of death in the United States where it is estimated that one in three seniors dies with AD or another dementia. Are modern lifestyle habits a contributing factor? Increased carbohydrate (sugar) consumption, stress and disruption of sleep patterns are quickly becoming the norm rather than the exception. Interestingly, seven months on a non-invasive high sucrose diet (20% sucrose in drinking water) has been shown to induce behavioral, metabolic and pathological changes consistent with AD in wild-type mice. As chronic stress and depression are associated with loss of locus coeruleus (LC) noradrenergic neurons and projections (source of anti-inflammatory and trophic factor control), we assessed the ability for a selective LC neurotoxin (DSP4) to accelerate and aggravate a high-sucrose mediated AD-related phenotype in wild-type mice. Male C57/Bl6 mice were divided into four groups: 1) saline injected, 2) DSP4 injected, 3) high sucrose drinking water (20%) or 4) DSP4 injected and high sucrose drinking water. We demonstrate that high sucrose consumption and DSP4 treatment promote an early-stage AD-related phenotype after only 3-4 months, as evidenced by elevated fecal corticosterone, increased despair, spatial memory deficits, increased AChE activity, elevated NO production, decreased pGSK3β and increased pTau. Combined treatment appears to accelerate and aggravate pathological processes consistent with Alzheimer disease and dementia. Developing a simple model in wild-type mice will highlight environmental and lifestyle factors that need to be addressed to slow, prevent or even reverse the rising trend in dementia patient numbers and cost.
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Affiliation(s)
- Pooja Choudhary
- Department of Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, S7N 5E5, Canada
| | - Anthony G Pacholko
- Department of Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, S7N 5E5, Canada
| | - Josh Palaschuk
- Department of Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, S7N 5E5, Canada
| | - Lane K Bekar
- Department of Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, S7N 5E5, Canada.
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O'Neill E, Harkin A. Targeting the noradrenergic system for anti-inflammatory and neuroprotective effects: implications for Parkinson's disease. Neural Regen Res 2018; 13:1332-1337. [PMID: 30106035 PMCID: PMC6108217 DOI: 10.4103/1673-5374.235219] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Degeneration of the locus coeruleus noradrenergic system is thought to play a key role in the pathogenesis of Parkinson's disease (PD), whereas pharmacological approaches to increase noradrenaline bioavailability may provide neuroprotection. Noradrenaline inhibits microglial activation and suppresses pro-inflammatory mediator production (e.g., tumor necrosis factor-α, interleukin-1β & inducible nitric oxide synthase activity), thus limiting the cytotoxicity of midbrain dopaminergic neurons in response to an inflammatory stimulus. Neighbouring astrocyte populations promote a neurotrophic environment in response to β2-adrenoceptor (β2-AR) stimulation via the production of growth factors (e.g., brain derived neurotrophic factor, cerebral dopamine neurotrophic factor & glial cell derived neurotrophic factor which have shown promising neuroprotective and neuro-restorative effects in the nigrostriatal dopaminergic system. More recent findings have demonstrated a role for the β2-AR in down-regulating expression levels of the human α-synuclein gene SNCA and relative α-synuclein protein abundance. Given that α-synuclein is a major protein constituent of Lewy body pathology, a hallmark neuropathological feature in Parkinson's disease, these findings could open up new avenues for pharmacological intervention strategies aimed at alleviating the burden of α-synucleinopathies in the Parkinsonian brain. In essence, the literature reviewed herein supports our hypothesis of a tripartite neuroprotective role for noradrenaline in combating PD-related neuropathology and motor dysfunction via (1) inhibiting nigral microglial activation & pro-inflammatory mediator production, (2) promoting the synthesis of neurotrophic factors from midbrain astrocytes and (3) downregulating α-synuclein gene expression and protein abundance in a β2-AR-dependent manner. Thus, taken together, either pharmacologically enhancing extra-synaptic noradrenaline bioavailability or targeting glial β2-ARs directly makes itself as a promising treatment option aimed at slowing/halting PD progression.
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Affiliation(s)
- Eoin O'Neill
- Neuropsychopharmacology Research Group, School of Pharmacy and Pharmaceutical Sciences & Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland
| | - Andrew Harkin
- Neuropsychopharmacology Research Group, School of Pharmacy and Pharmaceutical Sciences & Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland
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Melkonyan MM, Hunanyan L, Lourhmati A, Layer N, Beer-Hammer S, Yenkoyan K, Schwab M, Danielyan L. Neuroprotective, Neurogenic, and Amyloid Beta Reducing Effect of a Novel Alpha 2-Adrenoblocker, Mesedin, on Astroglia and Neuronal Progenitors upon Hypoxia and Glutamate Exposure. Int J Mol Sci 2017; 19:ijms19010009. [PMID: 29267189 PMCID: PMC5795961 DOI: 10.3390/ijms19010009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 12/17/2017] [Accepted: 12/19/2017] [Indexed: 12/17/2022] Open
Abstract
Locus coeruleus-noradrenergic system dysfunction is known to contribute to the progression of Alzheimer’s disease (AD). Besides a variety of reports showing the involvement of norepinephrine and its receptor systems in cognition, amyloid β (Aβ) metabolism, neuroinflammation, and neurogenesis, little is known about the contribution of the specific receptors to these actions. Here, we investigated the neurogenic and neuroprotective properties of a new α2 adrenoblocker, mesedin, in astroglial primary cultures (APC) from C57BL/6 and 3×Tg-AD mice. Our results demonstrate that mesedin rescues neuronal precursors and young neurons, and reduces the lactate dehydrogenase (LDH) release from astroglia under hypoxic and normoxic conditions. Mesedin also increased choline acetyltransferase, postsynaptic density marker 95 (PSD95), and Aβ-degrading enzyme neprilysin in the wild type APC, while in the 3×Tg-AD APC exposed to glutamate, it decreased the intracellular content of Aβ and enhanced the survival of synaptophysin-positive astroglia and neurons. These effects in APC can at least partially be attributed to the mesedin’s ability of increasing the expression of Interleukine(IL)-10, which is a potent anti-inflammatory, neuroprotective neurogenic, and Aβ metabolism enhancing factor. In summary, our data identify the neurogenic, neuroprotective, and anti-amyloidogenic action of mesedin in APC. Further in vivo studies are needed to estimate the therapeutic value of mesedin for AD.
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Affiliation(s)
- Magda M Melkonyan
- Department of Medical Chemistry, Yerevan state Medical University after M. Heratsi, 2 Koryun St., Yerevan 0025, Armenia.
| | - Lilit Hunanyan
- Department of Medical Chemistry, Yerevan state Medical University after M. Heratsi, 2 Koryun St., Yerevan 0025, Armenia.
| | - Ali Lourhmati
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany.
| | - Nikolas Layer
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany.
| | - Sandra Beer-Hammer
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology and ICePhA, University of Tuebingen, Wilhelmstr. 56, D-72076 Tübingen, Germany.
| | - Konstantin Yenkoyan
- Biochemistry Department, Yerevan state Medical University after M. Heratsi, 2 Koryun St., Yerevan 0025, Armenia.
| | - Matthias Schwab
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany.
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, University of Tübingen, Stuttgart, Auerbachstr. 112, D-70376 Stuttgart, Germany.
- Department of Pharmacy and Biochemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany.
| | - Lusine Danielyan
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany.
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Bekar LK, Wei HS, Nedergaard M. The locus coeruleus-norepinephrine network optimizes coupling of cerebral blood volume with oxygen demand. J Cereb Blood Flow Metab 2012; 32:2135-45. [PMID: 22872230 PMCID: PMC3519408 DOI: 10.1038/jcbfm.2012.115] [Citation(s) in RCA: 133] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Given the brain's uniquely high cell density and tissue oxygen levels bordering on hypoxia, the ability to rapidly and precisely match blood flow to constantly changing patterns in neural activity is an essential feature of cerebrovascular regulation. Locus coeruleus-norepinephrine (LC-NE) projections innervate the cerebral vasculature and can mediate vasoconstriction. However, function of the LC-mediated constriction in blood-flow regulation has never been addressed. Here, using intrinsic optical imaging coupled with an anesthesia regimen that only minimally interferes with LC activity, we show that NE enhances spatial and temporal aspects of functional hyperemia in the mouse somatosensory cortex. Increasing NE levels in the cortex using an α(2)-adrenergic receptor antagonist paradoxically reduces the extent of functional hyperemia while enhancing the surround blood-flow reduction. However, the NE-mediated vasoconstriction optimizes spatial and temporal focusing of the hyperemic response resulting in a sixfold decrease in the disparity between blood volume and oxygen demand. In addition, NE-mediated vasoconstriction accelerated redistribution to subsequently active regions, enhancing temporal synchronization of blood delivery. These observations show an important role for NE in optimizing neurovascular coupling. As LC neuron loss is prominent in Alzheimer and Parkinson diseases, the diminished ability to couple blood volume to oxygen demand may contribute to their pathogenesis.
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Affiliation(s)
- Lane K Bekar
- Division of Glia Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, New York, USA.
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Polak PE, Kalinin S, Braun D, Sharp A, Lin SX, Feinstein DL. The vincamine derivative vindeburnol provides benefit in a mouse model of multiple sclerosis: effects on the Locus coeruleus. J Neurochem 2012; 121:206-16. [PMID: 22288774 DOI: 10.1111/j.1471-4159.2012.07673.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The endogenous neurotransmitter noradrenaline (NA) plays several roles in maintaining brain homeostasis, including exerting anti-inflammatory and neuroprotective effects. The primary source of NA in the CNS are tyrosine hydroxylase (TH)-positive neurons located in the Locus coeruleus (LC) which send projections throughout the brain and spinal cord. We recently demonstrated that dysregulation of the LC:Noradrenergic system occurs in experimental autoimmune encephalomyelitis as well as in MS patients, associated with damage occurring to LC neurons. Vindeburnol, a structural analog of the cerebral vasodilator vincamine, was previously reported to increase TH expression and activity in LC neurons. Female C57BL/6 mice were immunized with myelin oligodendrocyte glycoprotein (MOG)(35-55) peptide, and treated with vindeburnol at the first appearance of clinical signs. Clinical signs continued to increase for about 1 week, at which point mice in the vehicle group continued to worsen while vindeburnol-treated mice showed improvement. Pro-inflammatory cytokine production from splenic T cells was not reduced by vindeburnol suggesting primarily central actions of treatment. In the cerebellum, vindeburnol decreased astrocyte activation and reduced the number of demyelinated regions. Vindeburnol reduced astrocyte activation in the LC, reduced TH+ neuronal hypertrophy, increased expression of several genes involved in LC survival and maturation, and increased NA levels in the spinal cord. These results suggest that treatments with drugs such as vindeburnol which target LC survival or function could be of benefit in MS patients.
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Affiliation(s)
- Paul E Polak
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, Illinois, USA
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Millan MJ. From the cell to the clinic: a comparative review of the partial D₂/D₃receptor agonist and α2-adrenoceptor antagonist, piribedil, in the treatment of Parkinson's disease. Pharmacol Ther 2010; 128:229-73. [PMID: 20600305 DOI: 10.1016/j.pharmthera.2010.06.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2010] [Indexed: 12/16/2022]
Abstract
Though L-3,4-dihydroxyphenylalanine (L-DOPA) is universally employed for alleviation of motor dysfunction in Parkinson's disease (PD), it is poorly-effective against co-morbid symptoms like cognitive impairment and depression. Further, it elicits dyskinesia, its pharmacokinetics are highly variable, and efficacy wanes upon long-term administration. Accordingly, "dopaminergic agonists" are increasingly employed both as adjuncts to L-DOPA and as monotherapy. While all recognize dopamine D(2) receptors, they display contrasting patterns of interaction with other classes of monoaminergic receptor. For example, pramipexole and ropinirole are high efficacy agonists at D(2) and D(3) receptors, while pergolide recognizes D(1), D(2) and D(3) receptors and a broad suite of serotonergic receptors. Interestingly, several antiparkinson drugs display modest efficacy at D(2) receptors. Of these, piribedil displays the unique cellular signature of: 1), signal-specific partial agonist actions at dopamine D(2)and D(3) receptors; 2), antagonist properties at α(2)-adrenoceptors and 3), minimal interaction with serotonergic receptors. Dopamine-deprived striatal D(2) receptors are supersensitive in PD, so partial agonism is sufficient for relief of motor dysfunction while limiting undesirable effects due to "over-dosage" of "normosensitive" D(2) receptors elsewhere. Further, α(2)-adrenoceptor antagonism reinforces adrenergic, dopaminergic and cholinergic transmission to favourably influence motor function, cognition, mood and the integrity of dopaminergic neurones. In reviewing the above issues, the present paper focuses on the distinctive cellular, preclinical and therapeutic profile of piribedil, comparisons to pramipexole, ropinirole and pergolide, and the core triad of symptoms that characterises PD-motor dysfunction, depressed mood and cognitive impairment. The article concludes by highlighting perspectives for clarifying the mechanisms of action of piribedil and other antiparkinson agents, and for optimizing their clinical exploitation.
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Affiliation(s)
- Mark J Millan
- Dept of Psychopharmacology, Institut de Recherches Servier, 125 Chemin de Ronde, 78290 Croissy/Seine (Paris), France.
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Simonini MV, Polak PE, Sharp A, McGuire S, Galea E, Feinstein DL. Increasing CNS noradrenaline reduces EAE severity. J Neuroimmune Pharmacol 2009; 5:252-9. [PMID: 19957206 DOI: 10.1007/s11481-009-9182-2] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 11/11/2009] [Indexed: 11/29/2022]
Abstract
The endogenous neurotransmitter noradrenaline (NA) is known to exert potent anti-inflammatory effects in glial cells, as well as provide neuroprotection against excitatory and inflammatory stimuli. These properties raise the possibility that increasing levels of NA in the central nervous system (CNS) could provide benefit in neurological diseases and conditions containing an inflammatory component. In the current study, we tested this possibility by examining the consequences of selectively modulating CNS NA levels on the development of clinical signs in experimental autoimmune encephalomyelitis (EAE). In mice immunized with myelin oligodendrocyte glycoprotein peptide to develop a chronic disease, pretreatment to selectively deplete CNS NA levels exacerbated clinical scores. Elevation of NA levels using the selective NA reuptake inhibitor atomoxetine did not affect clinical scores, while treatment of immunized mice with the synthetic NA precursor L-threo-3,4-dihydroxyphenylserine (L-DOPS) prevented further worsening. In contrast, treatment of mice with a combination of atomoxetine and L-DOPS led to significant improvement in clinical scores as compared to the control group. The combined treatment reduced astrocyte activation in the molecular layer of the cerebellum as assessed by staining for glial fibrillary protein but did not affect Th1 or Th17 type cytokine production from splenic T cells. These data suggest that selective elevation of CNS NA levels could provide benefit in EAE and multiple sclerosis without influencing peripheral immune responses.
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The effects of selenium against cerebral ischemia-reperfusion injury in rats. Neurosci Lett 2008; 438:265-9. [DOI: 10.1016/j.neulet.2008.03.091] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Revised: 02/27/2008] [Accepted: 03/07/2008] [Indexed: 11/17/2022]
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Kalinin S, Polak PE, Madrigal JLM, Gavrilyuk V, Sharp A, Chauhan N, Marien M, Colpaert F, Feinstein DL. Beta-amyloid-dependent expression of NOS2 in neurons: prevention by an alpha2-adrenergic antagonist. Antioxid Redox Signal 2006; 8:873-83. [PMID: 16771677 DOI: 10.1089/ars.2006.8.873] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The neurotransmitter noradrenaline (NA) exerts important antiinflammatory effects on glial cells including suppression of the inducible form of nitric oxide synthase (NOS2). The authors examined the consequences of manipulating NA in vivo by treating adult rats with the neurotoxin DSP4, which selectively lesions noradrenergic neurons of the locus ceruleus (LC), and reduces cortical NA levels. Following LC lesion, intracortical injection of aggregated amyloid beta 1-42 (Abeta1-42) caused appearance of NOS2 within neurons, and increased neuronal damage assessed by staining for nonphosphorylated neurofilament proteins with antibody SMI-32. Co-treatment with a selective alpha2-adrenergic antagonist reduced neuronal NOS2 staining as well as SMI-32 staining. Neuronal damage was dependent on NOS2 expression since injection of Abeta1-42 into DSP4-treated NOS2-deficient mice did not result in neuronal damage. These results demonstrate that decrease of NA levels in vivo can exacerbate inflammatory responses and neuronal damage due to inflammatory stimuli such as Abeta. These findings suggest that alpha2-adrenergic antagonists could provide therapeutic benefit in neurological diseases such as AD or PD where LC loss is known to occur.
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Affiliation(s)
- Sergey Kalinin
- Department of Anesthesiology, University of Illinois, Chicago, 60612, USA
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Scalabrino G, Mutti E, Veber D, Aloe L, Corsi MM, Galbiati S, Tredici G. Increased spinal cord NGF levels in rats with cobalamin (vitamin B12) deficiency. Neurosci Lett 2006; 396:153-8. [PMID: 16352395 DOI: 10.1016/j.neulet.2005.11.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2005] [Revised: 11/08/2005] [Accepted: 11/13/2005] [Indexed: 01/24/2023]
Abstract
We have recently demonstrated that the neuropathological morphological alterations caused by cobalamin (Cbl) deficiency in the rat central nervous system are related to the vitamin's inability to modulate the synthesis of some neurotoxic and neurotrophic agents in opposite directions. In the present study, we measured nerve growth factor (NGF) levels in the spinal cord (SC) and cerebrospinal fluid (CSF) of rats made Cbl-deficient (Cbl-D) by means of total gastrectomy (TG) or a Cbl-D diet. In both cases, Cbl deficiency increased SC and CSF NGF levels after the appearance of myelinolytic lesions in the SC white matter (SCWM) (i.e. after the second post-TG month), and these changes were normalised by Cbl treatment in the 4-month-totally-gastrectomised (TGX) rats. Intracerebroventricular (i.c.v.) anti-NGF-antibody treatment prevented the onset of the myelinolytic SCWM lesions in the 2-month-TGX rats (i.e. when SC and CSF NGF levels are still normal) and normalised the ultrastructure of the SCWM in the 4-month-TGX rats, which was however worsened by the i.c.v. administration of NGF. These findings demonstrate that: (i) Cbl deficiency increases SC and CSF NGF levels; and (ii) endogenous NGF seems to play a noxious role in the progression of rat Cbl-D central neuropathy.
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Affiliation(s)
- Giuseppe Scalabrino
- Institute of General Pathology, University of Milan, Via Mangiagalli 31, 20133 Milano, Italy.
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