1
|
Rafi H, Rafiq H, Farhan M. Pharmacological profile of agmatine: An in-depth overview. Neuropeptides 2024; 105:102429. [PMID: 38608401 DOI: 10.1016/j.npep.2024.102429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 03/14/2024] [Accepted: 04/01/2024] [Indexed: 04/14/2024]
Abstract
Agmatine, a naturally occurring polyamine derived from arginine via arginine decarboxylase, has been shown to play multifaceted roles in the mammalian body, impacting a wide range of physiological and pathological processes. This comprehensive review delineates the significant insights into agmatine's pharmacological profile, emphasizing its structure and metabolism, neurotransmission and regulation, and pharmacokinetics and function. Agmatine's biosynthesis is highly conserved across species, highlighting its fundamental role in cellular functions. In the brain, comparable to established neurotransmitters, agmatine acts as a neuromodulator, influencing the regulation, metabolism, and reabsorption of neurotransmitters that are key to mood disorders, learning, cognition, and the management of anxiety and depression. Beyond its neuromodulatory functions, agmatine exhibits protective effects across various cellular and systemic contexts, including neuroprotection, nephroprotection, cardioprotection, and cytoprotection, suggesting a broad therapeutic potential. The review explores agmatine's interaction with multiple receptor systems, including NMDA, α2-adrenoceptors, and imidazoline receptors, elucidating its role in enhancing cell viability, neuronal protection, and synaptic plasticity. Such interactions underpin agmatine's potential in treating neurological diseases and mood disorders, among other conditions. Furthermore, agmatine's pharmacokinetics, including its absorption, distribution, metabolism, and excretion, are discussed, underlining the complexity of its action and the potential for therapeutic application. The safety and efficacy of agmatine supplementation, demonstrated through various animal and human studies, affirm its potential as a beneficial therapeutic agent. Conclusively, the diverse physiological and therapeutic effects of agmatine, spanning neurotransmission, protection against cellular damage, and modulation of various receptor pathways, position it as a promising candidate for further research and clinical application. This review underscores the imperative for continued exploration into agmatine's mechanisms of action and its potential in pharmacology and medicine, promising advances in the treatment of numerous conditions.
Collapse
Affiliation(s)
- Hira Rafi
- Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Department of Biochemistry, University of Karachi, Pakistan.
| | - Hamna Rafiq
- Department of Biochemistry, University of Karachi, Pakistan
| | | |
Collapse
|
2
|
You Y, Chen Z, Hu WW. The role of microglia heterogeneity in synaptic plasticity and brain disorders: Will sequencing shed light on the discovery of new therapeutic targets? Pharmacol Ther 2024; 255:108606. [PMID: 38346477 DOI: 10.1016/j.pharmthera.2024.108606] [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: 10/31/2023] [Revised: 01/05/2024] [Accepted: 02/02/2024] [Indexed: 02/18/2024]
Abstract
Microglia play a crucial role in interacting with neuronal synapses and modulating synaptic plasticity. This function is particularly significant during postnatal development, as microglia are responsible for removing excessive synapses to prevent neurodevelopmental deficits. Dysregulation of microglial synaptic function has been well-documented in various pathological conditions, notably Alzheimer's disease and multiple sclerosis. The recent application of RNA sequencing has provided a powerful and unbiased means to decipher spatial and temporal microglial heterogeneity. By identifying microglia with varying gene expression profiles, researchers have defined multiple subgroups of microglia associated with specific pathological states, including disease-associated microglia, interferon-responsive microglia, proliferating microglia, and inflamed microglia in multiple sclerosis, among others. However, the functional roles of these distinct subgroups remain inadequately characterized. This review aims to refine our current understanding of the potential roles of heterogeneous microglia in regulating synaptic plasticity and their implications for various brain disorders, drawing from recent sequencing research and functional studies. This knowledge may aid in the identification of pathogenetic biomarkers and potential factors contributing to pathogenesis, shedding new light on the discovery of novel drug targets. The field of sequencing-based data mining is evolving toward a multi-omics approach. With advances in viral tools for precise microglial regulation and the development of brain organoid models, we are poised to elucidate the functional roles of microglial subgroups detected through sequencing analysis, ultimately identifying valuable therapeutic targets.
Collapse
Affiliation(s)
- Yi You
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Zhong Chen
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China; Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Wei-Wei Hu
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China.
| |
Collapse
|
3
|
Clements BM, Peterson CD, Kitto KF, Caye LD, Wilcox GL, Fairbanks CA. Biodistribution of Agmatine to Brain and Spinal Cord after Systemic Delivery. J Pharmacol Exp Ther 2023; 387:328-336. [PMID: 37770201 PMCID: PMC10658908 DOI: 10.1124/jpet.123.001828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 08/28/2023] [Accepted: 09/11/2023] [Indexed: 10/03/2023] Open
Abstract
Agmatine, an endogenous polyamine, has been shown to reduce chronic pain behaviors in animal models and in patients. This reduction is due to inhibition of the GluN2B subunit of the N-methyl-D-aspartate receptor (NMDAR) in the central nervous system (CNS). The mechanism of action requires central activity, but the extent to which agmatine crosses biologic barriers such as the blood-brain barrier (BBB) and intestinal epithelium is incompletely understood. Determination of agmatine distribution is limited by analytical protocols with low sensitivity and/or inefficient preparation. This study validated a novel bioanalytical protocol using high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) for quantification of agmatine in rat biologic matrices. These protocols were then used to determine the plasma pharmacokinetics of agmatine and the extent of distribution to the CNS. Precision and accuracy of the protocol met US Food and Drug Administration (FDA) standards in surrogate matrix as well as in corrected concentrations in appropriate matrices. The protocol also adequately withstood stability and dilution conditions. Upon application of this protocol to pharmacokinetic study, intravenous agmatine showed a half-life in plasma ranging between 18.9 and 14.9 minutes. Oral administration led to a prolonged plasma half-life (74.4-117 minutes), suggesting flip-flop kinetics, with bioavailability determined to be 29%-35%. Intravenous administration led to a rapid increase in agmatine concentration in brain but a delayed distribution and lower concentrations in spinal cord. However, half-life of agmatine in both tissues is substantially longer than in plasma. These data suggest that agmatine adequately crosses biologic barriers in rat and that brain and spinal cord pharmacokinetics can be functionally distinct. SIGNIFICANCE STATEMENT: Agmatine has been shown to be an effective nonopioid therapy for chronic pain, a significantly unmet medical necessity. Here, using a novel bioanalytical protocol for quantification of agmatine, we present the plasma pharmacokinetics and the first report of agmatine oral bioavailability as well as variable pharmacokinetics across different central nervous system tissues. These data provide a distributional rationale for the pharmacological effects of agmatine as well as new evidence for kinetic differences between brain and spinal cord.
Collapse
Affiliation(s)
- Benjamin M Clements
- Department of Pharmaceutics (B.M.C., C.D.P., C.A.F.), Department of Pharmacology (L.D.C., G.L.W., C.A.F.), Department of Neuroscience (K.F.K., G.L.W., C.A.F.), and Department of Dermatology (G.L.W.), University of Minnesota, Minneapolis, Minnesota
| | - Cristina D Peterson
- Department of Pharmaceutics (B.M.C., C.D.P., C.A.F.), Department of Pharmacology (L.D.C., G.L.W., C.A.F.), Department of Neuroscience (K.F.K., G.L.W., C.A.F.), and Department of Dermatology (G.L.W.), University of Minnesota, Minneapolis, Minnesota
| | - Kelley F Kitto
- Department of Pharmaceutics (B.M.C., C.D.P., C.A.F.), Department of Pharmacology (L.D.C., G.L.W., C.A.F.), Department of Neuroscience (K.F.K., G.L.W., C.A.F.), and Department of Dermatology (G.L.W.), University of Minnesota, Minneapolis, Minnesota
| | - Lukas D Caye
- Department of Pharmaceutics (B.M.C., C.D.P., C.A.F.), Department of Pharmacology (L.D.C., G.L.W., C.A.F.), Department of Neuroscience (K.F.K., G.L.W., C.A.F.), and Department of Dermatology (G.L.W.), University of Minnesota, Minneapolis, Minnesota
| | - George L Wilcox
- Department of Pharmaceutics (B.M.C., C.D.P., C.A.F.), Department of Pharmacology (L.D.C., G.L.W., C.A.F.), Department of Neuroscience (K.F.K., G.L.W., C.A.F.), and Department of Dermatology (G.L.W.), University of Minnesota, Minneapolis, Minnesota
| | - Carolyn A Fairbanks
- Department of Pharmaceutics (B.M.C., C.D.P., C.A.F.), Department of Pharmacology (L.D.C., G.L.W., C.A.F.), Department of Neuroscience (K.F.K., G.L.W., C.A.F.), and Department of Dermatology (G.L.W.), University of Minnesota, Minneapolis, Minnesota
| |
Collapse
|
4
|
Saha P, Panda S, Holkar A, Vashishth R, Rana SS, Arumugam M, Ashraf GM, Haque S, Ahmad F. Neuroprotection by agmatine: Possible involvement of the gut microbiome? Ageing Res Rev 2023; 91:102056. [PMID: 37673131 DOI: 10.1016/j.arr.2023.102056] [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: 06/05/2023] [Revised: 08/09/2023] [Accepted: 08/31/2023] [Indexed: 09/08/2023]
Abstract
Agmatine, an endogenous polyamine derived from L-arginine, elicits tremendous multimodal neuromodulant properties. Alterations in agmatinergic signalling are closely linked to the pathogeneses of several brain disorders. Importantly, exogenous agmatine has been shown to act as a potent neuroprotectant in varied pathologies, including brain ageing and associated comorbidities. The antioxidant, anxiolytic, analgesic, antidepressant and memory-enhancing activities of agmatine may derive from its ability to regulate several cellular pathways; including cell metabolism, survival and differentiation, nitric oxide signalling, protein translation, oxidative homeostasis and neurotransmitter signalling. This review briefly discusses mammalian metabolism of agmatine and then proceeds to summarize our current understanding of neuromodulation and neuroprotection mediated by agmatine. Further, the emerging exciting bidirectional links between agmatine and the resident gut microbiome and their implications for brain pathophysiology and ageing are also discussed.
Collapse
Affiliation(s)
- Priyanka Saha
- Department of Biotechnology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, India
| | - Subhrajita Panda
- Department of Biotechnology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, India
| | - Aayusha Holkar
- Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, India
| | - Rahul Vashishth
- Department of Biosciences, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, India
| | - Sandeep Singh Rana
- Department of Biosciences, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, India
| | - Mohanapriya Arumugam
- Department of Biotechnology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, India
| | - Ghulam Md Ashraf
- University of Sharjah, College of Health Sciences, and Research Institute for Medical and Health Sciences, Department of Medical Laboratory Sciences, Sharjah 27272, United Arab Emirates.
| | - Shafiul Haque
- Research and Scientific Studies Unit, College of Nursing and Allied Health Sciences, Jazan University, Jazan 45142, Saudi Arabia; Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Beirut, Lebanon; Centre of Medical and Bio-Allied Health Sciences Research, Ajman University, Ajman, United Arab Emirates
| | - Faraz Ahmad
- Department of Biotechnology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, India.
| |
Collapse
|
5
|
Cox MF, Hascup ER, Bartke A, Hascup KN. Friend or Foe? Defining the Role of Glutamate in Aging and Alzheimer’s Disease. FRONTIERS IN AGING 2022; 3:929474. [PMID: 35821835 PMCID: PMC9261322 DOI: 10.3389/fragi.2022.929474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 05/17/2022] [Indexed: 11/13/2022]
Abstract
Aging is a naturally occurring decline of physiological processes and biological pathways that affects both the structural and functional integrity of the body and brain. These physiological changes reduce motor skills, executive function, memory recall, and processing speeds. Aging is also a major risk factor for multiple neurodegenerative disorders including Alzheimer’s disease (AD). Identifying a biomarker, or biomarkers, that signals the transition from physiological to pathological aging would aid in earlier therapeutic options or interventional strategies. Considering the importance of glutamate signaling in synaptic plasticity, motor movement, and cognition, this neurotransmitter serves as a juncture between cognitive health and disease. This article discusses glutamatergic signaling during physiological aging and the pathological changes observed in AD patients. Findings from studies in mouse models of successful aging and AD are reviewed and provide a biological context for this transition. Finally, current techniques to monitor brain glutamate are highlighted. These techniques may aid in elucidating time-point specific therapeutic windows to modify disease outcome.
Collapse
Affiliation(s)
- MaKayla F. Cox
- Dale and Deborah Smith Center for Alzheimer’s Research and Treatment, Department of Neurology, Neurosciences Institute, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Erin R. Hascup
- Dale and Deborah Smith Center for Alzheimer’s Research and Treatment, Department of Neurology, Neurosciences Institute, Southern Illinois University School of Medicine, Springfield, IL, United States
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Andrzej Bartke
- Dale and Deborah Smith Center for Alzheimer’s Research and Treatment, Department of Neurology, Neurosciences Institute, Southern Illinois University School of Medicine, Springfield, IL, United States
- Department of Internal Medicine, Southern Illinois University School of Medicine, Springfield, IL, United States
- Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Kevin N. Hascup
- Dale and Deborah Smith Center for Alzheimer’s Research and Treatment, Department of Neurology, Neurosciences Institute, Southern Illinois University School of Medicine, Springfield, IL, United States
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
- Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL, United States
- *Correspondence: Kevin N. Hascup,
| |
Collapse
|
6
|
Bernstein HG, Keilhoff G, Laube G, Dobrowolny H, Steiner J. Polyamines and polyamine-metabolizing enzymes in schizophrenia: Current knowledge and concepts of therapy. World J Psychiatry 2021; 11:1177-1190. [PMID: 35070769 PMCID: PMC8717027 DOI: 10.5498/wjp.v11.i12.1177] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/30/2021] [Accepted: 11/25/2021] [Indexed: 02/06/2023] Open
Abstract
Polyamines play preeminent roles in a variety of cellular functions in the central nervous system and other organs. A large body of evidence suggests that the polyamine pathway is prominently involved in the etiology and pathology of schizophrenia. Alterations in the expression and activity of polyamine metabolizing enzymes, as well as changes in the levels of the individual polyamines, their precursors and derivatives, have been measured in schizophrenia and animal models of the disease. Additionally, neuroleptic treatment has been shown to influence polyamine concentrations in brain and blood of individuals with schizophrenia. Thus, the polyamine system may appear to be a promising target for neuropharmacological treatment of schizophrenia. However, for a number of practical reasons there is currently only limited hope for a polyamine-based schizophrenia therapy.
Collapse
Affiliation(s)
- Hans-Gert Bernstein
- Department of Psychiatry, University of Magdeburg, Magdeburg D-39116, Saxony-Anhalt, Germany
| | - Gerburg Keilhoff
- Institute of Biochemistry and Cell Biology, University of Magdeburg, Magdeburg D-39116, Saxony-Anhalt, Germany
| | - Gregor Laube
- Department of Anatomy, Charite, Berlin D-10117, Germany
| | - Henrik Dobrowolny
- Department of Psychiatry, University of Magdeburg, Magdeburg D-39116, Saxony-Anhalt, Germany
| | - Johann Steiner
- Department of Psychiatry, University of Magdeburg, Magdeburg D-39116, Saxony-Anhalt, Germany
| |
Collapse
|
7
|
Gasiorowska A, Wydrych M, Drapich P, Zadrozny M, Steczkowska M, Niewiadomski W, Niewiadomska G. The Biology and Pathobiology of Glutamatergic, Cholinergic, and Dopaminergic Signaling in the Aging Brain. Front Aging Neurosci 2021; 13:654931. [PMID: 34326765 PMCID: PMC8315271 DOI: 10.3389/fnagi.2021.654931] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 06/14/2021] [Indexed: 12/12/2022] Open
Abstract
The elderly population is growing worldwide, with important health and socioeconomic implications. Clinical and experimental studies on aging have uncovered numerous changes in the brain, such as decreased neurogenesis, increased synaptic defects, greater metabolic stress, and enhanced inflammation. These changes are associated with cognitive decline and neurobehavioral deficits. Although aging is not a disease, it is a significant risk factor for functional worsening, affective impairment, disease exaggeration, dementia, and general disease susceptibility. Conversely, life events related to mental stress and trauma can also lead to accelerated age-associated disorders and dementia. Here, we review human studies and studies on mice and rats, such as those modeling human neurodegenerative diseases, that have helped elucidate (1) the dynamics and mechanisms underlying the biological and pathological aging of the main projecting systems in the brain (glutamatergic, cholinergic, and dopaminergic) and (2) the effect of defective glutamatergic, cholinergic, and dopaminergic projection on disabilities associated with aging and neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases. Detailed knowledge of the mechanisms of age-related diseases can be an important element in the development of effective ways of treatment. In this context, we briefly analyze which adverse changes associated with neurodegenerative diseases in the cholinergic, glutaminergic and dopaminergic systems could be targeted by therapeutic strategies developed as a result of our better understanding of these damaging mechanisms.
Collapse
Affiliation(s)
- Anna Gasiorowska
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Malgorzata Wydrych
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Patrycja Drapich
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Maciej Zadrozny
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Marta Steczkowska
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Wiktor Niewiadomski
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Grazyna Niewiadomska
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| |
Collapse
|
8
|
Neis VB, Rosa PB, Olescowicz G, Rodrigues ALS. Therapeutic potential of agmatine for CNS disorders. Neurochem Int 2017; 108:318-331. [DOI: 10.1016/j.neuint.2017.05.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 05/06/2017] [Accepted: 05/12/2017] [Indexed: 12/14/2022]
|
9
|
Agmatine: multifunctional arginine metabolite and magic bullet in clinical neuroscience? Biochem J 2017; 474:2619-2640. [DOI: 10.1042/bcj20170007] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 05/23/2017] [Accepted: 05/25/2017] [Indexed: 12/12/2022]
Abstract
Agmatine, the decarboxylation product of arginine, was largely neglected as an important player in mammalian metabolism until the mid-1990s, when it was re-discovered as an endogenous ligand of imidazoline and α2-adrenergic receptors. Since then, a wide variety of agmatine-mediated effects have been observed, and consequently agmatine has moved from a wallflower existence into the limelight of clinical neuroscience research. Despite this quantum jump in scientific interest, the understanding of the anabolism and catabolism of this amine is still vague. The purification and biochemical characterization of natural mammalian arginine decarboxylase and agmatinase still are open issues. Nevertheless, the agmatinergic system is currently one of the most promising candidates in order to pharmacologically interfere with some major diseases of the central nervous system, which are summarized in the present review. Particularly with respect to major depression, agmatine, its derivatives, and metabolizing enzymes show great promise for the development of an improved treatment of this common disease.
Collapse
|
10
|
Liu P, Jing Y, Collie ND, Dean B, Bilkey DK, Zhang H. Altered brain arginine metabolism in schizophrenia. Transl Psychiatry 2016; 6:e871. [PMID: 27529679 PMCID: PMC5022089 DOI: 10.1038/tp.2016.144] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/07/2016] [Accepted: 06/15/2016] [Indexed: 12/24/2022] Open
Abstract
Previous research implicates altered metabolism of l-arginine, a versatile amino acid with a number of bioactive metabolites, in the pathogenesis of schizophrenia. The present study, for we believe the first time, systematically compared the metabolic profile of l-arginine in the frontal cortex (Brodmann's area 8) obtained post-mortem from schizophrenic individuals and age- and gender-matched non-psychiatric controls (n=20 per group). The enzyme assays revealed no change in total nitric oxide synthase (NOS) activity, but significantly increased arginase activity in the schizophrenia group. Western blot showed reduced endothelial NOS protein expression and increased arginase II protein level in the disease group. High-performance liquid chromatography and liquid chromatography/mass spectrometric assays confirmed significantly reduced levels of γ-aminobutyric acid (GABA), but increased agmatine concentration and glutamate/GABA ratio in the schizophrenia cases. Regression analysis indicated positive correlations between arginase activity and the age of disease onset and between l-ornithine level and the duration of illness. Moreover, cluster analyses revealed that l-arginine and its main metabolites l-citrulline, l-ornithine and agmatine formed distinct groups, which were altered in the schizophrenia group. The present study provides further evidence of altered brain arginine metabolism in schizophrenia, which enhances our understanding of the pathogenesis of schizophrenia and may lead to the future development of novel preventions and/or therapeutics for the disease.
Collapse
Affiliation(s)
- P Liu
- Department of Anatomy, University of Otago, Dunedin, New Zealand,Brain Health Research Centre, University of Otago, Dunedin, New Zealand,Department of Anatomy, University of Otago, Lindo Ferguson Building, 270 Great King Street, Dunedin 9016, New Zealand. E-mail:
| | - Y Jing
- Department of Anatomy, University of Otago, Dunedin, New Zealand,Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - N D Collie
- Department of Anatomy, University of Otago, Dunedin, New Zealand,Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - B Dean
- The Molecular Psychiatry Laboratory, The Florey Institute for Neuroscience and Mental Health, Parkville, VIC, Australia
| | - D K Bilkey
- Brain Health Research Centre, University of Otago, Dunedin, New Zealand,Department of Psychology, University of Otago, Dunedin, New Zealand
| | - H Zhang
- Brain Health Research Centre, University of Otago, Dunedin, New Zealand,School of Pharmacy, University of Otago, Dunedin, New Zealand
| |
Collapse
|