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Wang P, Guan X, Su X, Wu F, Xiu M. A pilot study to examine the association between COX-2 rs5275 polymorphism and the response to repetitive transcranial stimulation in schizophrenia. SCHIZOPHRENIA (HEIDELBERG, GERMANY) 2023; 9:56. [PMID: 37684257 PMCID: PMC10491610 DOI: 10.1038/s41537-023-00386-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 07/26/2023] [Indexed: 09/10/2023]
Abstract
High frequency (HF)-rTMS has been shown to improve cognitive functions in patients with schizophrenia (SCZ). This study aimed to investigate whether COX-2 rs5275 variants were associated with cognitive improvements following rTMS treatment in patients with SCZ. Forty-eight hospitalized patients with SCZ were assigned to the neuronavigation HF-rTMS group and 28 patients to the sham group over left DLPFC for 1 month. Cognitive function was evaluated using the repeatable battery for the assessment of neuropsychological status (RBANS) at weeks 0 and 4. COX-2 rs5275 polymorphism was genotyped by a technician. At baseline, C allele carriers showed better cognitive performance relative to patients with TT homozygote. Additionally, C allele carriers had greater improvement in memory from the follow-up to baseline following rTMS stimulation, while patients with the TT genotype showed no significant improvement in memory index. More importantly, we found that COX-2 rs5275 was correlated with the response to rTMS after controlling for the covariates. This study data indicate that COX-2 rs5275 was associated with improvements in immediate memory after HF-rTMS treatment in patients with SCZ. rTMS shows an effect on memory only in C allele carriers, but not in those with the TT genotype.
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Affiliation(s)
- Pingping Wang
- Neurology Department, Xuan Wu Hospital of Capital Medical University, Beijing, China
| | - Xiaoni Guan
- Peking University HuiLongGuan Clinical Medical School, Beijing HuiLongGuan Hospital, Beijing, China
| | - Xiuru Su
- Hebei Rongjun Hospital, Baoding, China
| | - Fengchun Wu
- Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China.
- Department of Biomedical Engineering, Guangzhou Medical University, Guangzhou, China.
- Guangdong Engineering Technology Research Center for Translational Medicine of Mental Disorders, Guangzhou, China.
| | - Meihong Xiu
- Peking University HuiLongGuan Clinical Medical School, Beijing HuiLongGuan Hospital, Beijing, China.
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2
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Orhan F, Goiny M, Becklén M, Mathé L, Piehl F, Schwieler L, Fatouros-Bergman H, Farde L, Cervenka S, Sellgren CM, Engberg G, Erhardt S. CSF dopamine is elevated in first-episode psychosis and associates to symptom severity and cognitive performance. Schizophr Res 2023; 257:34-40. [PMID: 37271040 DOI: 10.1016/j.schres.2023.05.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 01/13/2023] [Accepted: 05/11/2023] [Indexed: 06/06/2023]
Abstract
BACKGROUND The hypothesis of dopamine dysfunction in psychosis has evolved since the mid-twentieth century. However, clinical support from biochemical analysis of the transmitter in patients is still missing. The present study assessed dopamine and related metabolites in the cerebrospinal fluid (CSF) of first-episode psychosis (FEP) subjects. METHODS Forty first-episode psychosis subjects and twenty healthy age-matched volunteers were recruited via the Karolinska Schizophrenia Project, a multidisciplinary research consortium that investigates the pathophysiology of schizophrenia. Psychopathology, disease severity, and cognitive performance were rated as well as cerebrospinal fluid concentrations of dopamine and related metabolites were measured using a sensitive high-pressure liquid chromatography assay. RESULTS CSF dopamine was reliably detected in 50 % of healthy controls and in 65 % of first-episode psychosis subjects and significantly higher in first-episode psychosis subjects compared to age-matched healthy controls. No difference in CSF dopamine levels was observed between drug-naive subjects and subjects with short exposure to antipsychotics. The dopamine concentrations were positively associated with illness severity and deficits in executive functioning. CONCLUSIONS Dopamine dysfunction has long been considered a cornerstone of the pathophysiology of schizophrenia, although biochemical support for elevated brain dopamine levels has been lacking. The results of the present study, showing that FEP subjects have increased CSF dopamine levels that correlate to disease symptoms, should fill the knowledge gap in this regard.
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Affiliation(s)
- Funda Orhan
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Michel Goiny
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Meneca Becklén
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Levida Mathé
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Fredrik Piehl
- Neuroimmunology Unit, Department of Clinical Neuroscience, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Lilly Schwieler
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Helena Fatouros-Bergman
- Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm Health Care Services, Region Stockholm, Sweden
| | - Lars Farde
- Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm Health Care Services, Region Stockholm, Sweden
| | - Simon Cervenka
- Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm Health Care Services, Region Stockholm, Sweden
| | - Carl M Sellgren
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm Health Care Services, Region Stockholm, Sweden
| | - Göran Engberg
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
| | - Sophie Erhardt
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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3
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Savitz J, Ford BN, Kuplicki R, Khalsa S, Teague TK, Paulus MP. Acute administration of ibuprofen increases serum concentration of the neuroprotective kynurenine pathway metabolite, kynurenic acid: a pilot randomized, placebo-controlled, crossover study. Psychopharmacology (Berl) 2022; 239:3919-3927. [PMID: 36271950 PMCID: PMC10040216 DOI: 10.1007/s00213-022-06263-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 10/10/2022] [Indexed: 11/25/2022]
Abstract
RATIONALE At least six different types of antidepressant treatments have been shown to either increase the neuroprotective kynurenine pathway (KP) metabolite, kynurenic acid (KynA), or decrease the neurotoxic KP metabolite, quinolinic acid (QA). Nonsteroidal anti-inflammatory drugs (NSAIDs) including ibuprofen have shown some efficacy in the treatment of depression but their effects on the KP have not been studied in humans. OBJECTIVES To evaluate the effect of ibuprofen on circulating KP metabolites. METHODS In a randomized, placebo-controlled, crossover study, 20 healthy adults (10 women) received a single oral dose of 200-mg ibuprofen, 600-mg ibuprofen, or placebo in a counterbalanced order (NCT02507219). Serum samples were drawn in the mid-afternoon, 5 h after ibuprofen/placebo administration. KP metabolites were measured blind to visit by tandem mass spectrometry. Data were analyzed with linear mixed effect models. The primary outcome was KynA/QA and the secondary outcome was KynA. RESULTS After Bonferroni correction, there was a significant effect of treatment on KynA/QA. The effect was driven by an increase in KynA concentration after the 600-mg dose but not the 200-mg dose relative to placebo (Cohen's d = 1.71). In contrast, both the 200-mg (d = 1.03) and 600-mg (d = 2.05) doses of ibuprofen decreased tryptophan concentrations relative to placebo. CONCLUSIONS Given its KynA-elevating effects, ibuprofen could have neuroprotective effects in the context of depression as well as other neuroinflammatory disorders that are characterized by a reduction in KynA.
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Affiliation(s)
- Jonathan Savitz
- Laureate Institute for Brain Research, Tulsa, OK, USA.
- Oxley College of Health Sciences, The University of Tulsa, Tulsa, OK, USA.
| | - Bart N Ford
- Department of Pharmacology & Physiology, Oklahoma State University Center for Health Sciences, Tulsa, OK, USA
| | | | - Sahib Khalsa
- Laureate Institute for Brain Research, Tulsa, OK, USA
- Oxley College of Health Sciences, The University of Tulsa, Tulsa, OK, USA
| | - T Kent Teague
- Department of Surgery, University of Oklahoma School of Community Medicine, Tulsa, OK, USA
- Department of Psychiatry, University of Oklahoma School of Community Medicine, Tulsa, OK, USA
- Department of Pharmaceutical Sciences, University of Oklahoma College of Pharmacy, Tulsa, OK, USA
| | - Martin P Paulus
- Laureate Institute for Brain Research, Tulsa, OK, USA
- Oxley College of Health Sciences, The University of Tulsa, Tulsa, OK, USA
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4
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Imbeault S, Gubert Olivé M, Jungholm O, Erhardt S, Wigström H, Engberg G, Jardemark K. Blockade of KAT II Facilitates LTP in Kynurenine 3-Monooxygenase Depleted Mice. Int J Tryptophan Res 2021; 14:11786469211041368. [PMID: 34483669 PMCID: PMC8411644 DOI: 10.1177/11786469211041368] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 08/01/2021] [Indexed: 11/16/2022] Open
Abstract
Excess of brain kynurenic acid (KYNA), a neuroactive metabolite of the kynurenine
pathway, is known to elicit cognitive dysfunction. In the present study, we
investigated spatial working memory in mice with elevated levels of KYNA,
induced by targeted deletion of kynurenine 3-monooxygenase (KMO), as well as
long-term potentiation (LTP) of field excitatory postsynaptic potentials
(fEPSPs) in hippocampal brain slices from these mice. The KMO knock-out
(KMO−/−) mice performed more poorly in the spatial working memory
task as compared to their wild-type (WT) counterparts, as reflected by fewer
correct choices in a T-maze. Both fEPSPs, or LTP, did not significantly differ
between the 2 mouse strains. However, administration of PF-04859989, a
kynurenine aminotransferase (KAT) II inhibitor, limiting the production of KYNA,
facilitated fEPSP and enhanced LTP to a greater extent in hippocampal slices
from KMO−/− mice compared to WT mice. The results of the present
study point to an essential role for KYNA in modulating LTP in the hippocampus
of KMO−/− mice which may account for their dysfunctional spatial
working memory.
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Affiliation(s)
- Sophie Imbeault
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Max Gubert Olivé
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Oscar Jungholm
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Sophie Erhardt
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Holger Wigström
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Department of Medical Biophysics, Institute of Neuroscience and Physiology, University of Gothenburg, Sweden
| | - Göran Engberg
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Kent Jardemark
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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5
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Stone TW. Relationships and Interactions between Ionotropic Glutamate Receptors and Nicotinic Receptors in the CNS. Neuroscience 2021; 468:321-365. [PMID: 34111447 DOI: 10.1016/j.neuroscience.2021.06.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 06/03/2021] [Accepted: 06/04/2021] [Indexed: 02/07/2023]
Abstract
Although ionotropic glutamate receptors and nicotinic receptors for acetylcholine (ACh) have usually been studied separately, they are often co-localized and functionally inter-dependent. The objective of this review is to survey the evidence for interactions between the two receptor families and the mechanisms underlying them. These include the mutual regulation of subunit expression, which change the NMDA:AMPA response balance, and the existence of multi-functional receptor complexes which make it difficult to distinguish between individual receptor sites, especially in vivo. This is followed by analysis of the functional relationships between the receptors from work on transmitter release, cellular electrophysiology and aspects of behavior where these can contribute to understanding receptor interactions. It is clear that nicotinic receptors (nAChRs) on axonal terminals directly regulate the release of glutamate and other neurotransmitters, α7-nAChRs generally promoting release. Hence, α7-nAChR responses will be prevented not only by a nicotinic antagonist, but also by compounds blocking the indirectly activated glutamate receptors. This accounts for the apparent anticholinergic activity of some glutamate antagonists, including the endogenous antagonist kynurenic acid. The activation of presynaptic nAChRs is by the ambient levels of ACh released from pre-terminal synapses, varicosities and glial cells, acting as a 'volume neurotransmitter' on synaptic and extrasynaptic sites. In addition, ACh and glutamate are released as CNS co-transmitters, including 'cholinergic' synapses onto spinal Renshaw cells. It is concluded that ACh should be viewed primarily as a modulator of glutamatergic neurotransmission by regulating the release of glutamate presynaptically, and the location, subunit composition, subtype balance and sensitivity of glutamate receptors, and not primarily as a classical fast neurotransmitter. These conclusions and caveats should aid clarification of the sites of action of glutamate and nicotinic receptor ligands in the search for new centrally-acting drugs.
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Affiliation(s)
- Trevor W Stone
- The Kennedy Institute of Rheumatology, University of Oxford, Oxford OX3 7FY, UK; Institute of Neuroscience, University of Glasgow, G12 8QQ, UK.
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6
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Repeated administration of LPS exaggerates amphetamine-induced locomotor response and causes learning deficits in mice. J Neuroimmunol 2020; 349:577401. [PMID: 33002724 DOI: 10.1016/j.jneuroim.2020.577401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 09/03/2020] [Accepted: 09/18/2020] [Indexed: 12/12/2022]
Abstract
Immune activation contributes to the pathophysiology of psychiatric disorders. Administration of a single dose of lipopolysaccharides (LPS) has been shown to induce depressive- and anxiety-like behaviors in rodents through activation of the kynurenine pathway, increasing levels of the N-methyl-d-aspartate (NMDA) receptor agonist quinolinic acid. Conversely, repeated administration of LPS produces increased levels of the NMDA receptor antagonist kynurenic acid. Here we show that repeated LPS administration increases sensitivity to D-amphetamine and produces cognitive deficits and anxiety-like behavior. Together, our behavioral data suggests that repeated LPS administration may be useful to study the contribution of inflammation to psychiatric disorders such as schizophrenia.
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7
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López DE, Ballaz SJ. The Role of Brain Cyclooxygenase-2 (Cox-2) Beyond Neuroinflammation: Neuronal Homeostasis in Memory and Anxiety. Mol Neurobiol 2020; 57:5167-5176. [PMID: 32860157 DOI: 10.1007/s12035-020-02087-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 08/24/2020] [Indexed: 12/13/2022]
Abstract
Cyclooxygenases are a group of heme-containing isozymes (namely Cox-1 and Cox-2) that catalyze the conversion of arachidonic acid to largely bioactive prostaglandins (PGs). Cox-1 is the ubiquitous housekeeping enzyme, and the mitogen-inducible Cox-2 is activated to cause inflammation. Interestingly, Cox-2 is constitutively expressed in the brain at the postsynaptic dendrites and excitatory terminals of the cortical and spinal cord neurons. Neuronal Cox-2 is activated in response to synaptic excitation to yield PGE2, the predominant Cox-2 metabolite in the brain, which in turn stimulates the release of glutamate and neuronal firing in a retrograde fashion. Cox-2 is also engaged in the metabolism of new endocannabinoids from 2-arachidonoyl-glycerol to modulate their actions at presynaptic terminals. In addition to these interactions, the induction of neuronal Cox-2 is coupled to the trans-synaptic activation of the dopaminergic mesolimbic system and some serotoninergic receptors, which might contribute to the development of emotional behavior. Although much of the focus regarding the induction of Cox-2 in the brain has been centered on neuroinflammation-related neurodegenerative and psychiatric disorders, some evidence also suggests that Cox-2 release during neuronal signaling may be pivotal for the fine tuning of cortical networks to regulate behavior. This review compiles the evidence supporting the homeostatic role of neuronal Cox-2 in synaptic transmission and plasticity, since neuroinflammation is originally triggered by the induction of glial Cox-2 expression. The goal is to provide perspective on the roles of Cox-2 beyond neuroinflammation, such as those played in memory and anxiety, and whose evidence is still scant.
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Affiliation(s)
- Diana E López
- Biomedical Sciences Graduate Program, Yachay Tech University, Urcuquí, Ecuador
| | - Santiago J Ballaz
- School of Biological Sciences and Engineering, Yachay Tech University, Hacienda San José s/n, San Miguel de Urcuquí, Ecuador.
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8
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Maget A, Platzer M, Bengesser SA, Fellendorf FT, Birner A, Queissner R, Hamm C, Reininghaus B, Hecker A, Tomberger L, Pilz R, Dalkner N, Moll N, Schütze G, Schwarz M, Kapfhammer HP, Reininghaus EZ. Differences in Kynurenine Metabolism During Depressive, Manic, and Euthymic Phases of Bipolar Affective Disorder. Curr Top Med Chem 2020; 20:1344-1352. [DOI: 10.2174/1568026619666190802145128] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 05/29/2019] [Accepted: 06/27/2019] [Indexed: 11/22/2022]
Abstract
Background & Objectives:
The kynurenine pathway is involved in inflammatory diseases. Alterations
of this pathway were shown in psychiatric entities as well. The aim of this study was to determine
whether specific changes in kynurenine metabolism are associated with current mood symptoms in bipolar
disorder.
Methods:
Sum scores of the Hamilton Depression Scale, Beck Depression Inventory, and Young Mania
Rating Scale were collected from 156 bipolar individuals to build groups of depressive, manic and
euthymic subjects according to predefined cut-off scores. Severity of current mood symptoms was correlated
with activities of the enzymes kynurenine 3-monooxygenase (ratio of 3-hydroxykynurenine/
kynurenine), kynurenine aminotransferase (ratio of kynurenic acid/ kynurenine) and kynureninase (ratio of
3-hydroxyanthranilic acid/ 3-hydroxykynurenine), proxied by ratios of serum concentrations.
Results:
Individuals with manic symptoms showed a shift towards higher kynurenine 3-monooxygenase
activity (χ2 = 7.14, Df = 2, p = .028), compared to euthymic as well as depressed individuals. There were no
differences between groups regarding activity of kynurenine aminotransferase and kynureninase. Within
the group of depressed patients, Hamilton Depression Scale and kynurenine aminotransferase showed a
significant negative correlation (r = -0.41, p = .036), displaying lower metabolism in the direction of
kynurenic acid.
Conclusion:
Depression severity in bipolar disorder seems to be associated with a decreased synthesis of
putative neuroprotective kynurenic acid. Furthermore, higher kynurenine 3-monooxygenase activity in currently
manic individuals indicates an increased inflammatory state within bipolar disorder with more severe
inflammation during manic episodes. The underlying pathophysiological mechanisms of the different affective
episodes could represent parallel mechanisms rather than opposed processes.
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Affiliation(s)
- Alexander Maget
- Department of Psychiatric and Psychotherapeutic Medicine, Medical University of Graz, Graz, Austria
| | - Martina Platzer
- Department of Psychiatric and Psychotherapeutic Medicine, Medical University of Graz, Graz, Austria
| | - Susanne A. Bengesser
- Department of Psychiatric and Psychotherapeutic Medicine, Medical University of Graz, Graz, Austria
| | - Frederike T. Fellendorf
- Department of Psychiatric and Psychotherapeutic Medicine, Medical University of Graz, Graz, Austria
| | - Armin Birner
- Department of Psychiatric and Psychotherapeutic Medicine, Medical University of Graz, Graz, Austria
| | - Robert Queissner
- Department of Psychiatric and Psychotherapeutic Medicine, Medical University of Graz, Graz, Austria
| | - Carlo Hamm
- Department of Psychiatric and Psychotherapeutic Medicine, Medical University of Graz, Graz, Austria
| | - Bernd Reininghaus
- Department of Psychiatric and Psychotherapeutic Medicine, Medical University of Graz, Graz, Austria
| | - Andrzej Hecker
- Department of Psychiatric and Psychotherapeutic Medicine, Medical University of Graz, Graz, Austria
| | - Lukas Tomberger
- Department of Psychiatric and Psychotherapeutic Medicine, Medical University of Graz, Graz, Austria
| | - Renè Pilz
- Department of Psychiatric and Psychotherapeutic Medicine, Medical University of Graz, Graz, Austria
| | - Nina Dalkner
- Department of Psychiatric and Psychotherapeutic Medicine, Medical University of Graz, Graz, Austria
| | - Natalie Moll
- Institute of Laboratory Medicine Medical Center of Munich University (LMU), Munich, Germany
| | - Gregor Schütze
- Institute of Laboratory Medicine Medical Center of Munich University (LMU), Munich, Germany
| | - Markus Schwarz
- Institute of Laboratory Medicine Medical Center of Munich University (LMU), Munich, Germany
| | - Hans P. Kapfhammer
- Department of Psychiatric and Psychotherapeutic Medicine, Medical University of Graz, Graz, Austria
| | - Eva Z. Reininghaus
- Department of Psychiatric and Psychotherapeutic Medicine, Medical University of Graz, Graz, Austria
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10
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Tran HQ, Shin EJ, Saito K, Tran TV, Phan DH, Sharma N, Kim DW, Choi SY, Jeong JH, Jang CG, Cheong JH, Nabeshima T, Kim HC. Indoleamine-2,3-dioxygenase-1 is a molecular target for the protective activity of mood stabilizers against mania-like behavior induced by d-amphetamine. Food Chem Toxicol 2019; 136:110986. [PMID: 31760073 DOI: 10.1016/j.fct.2019.110986] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 11/17/2019] [Accepted: 11/18/2019] [Indexed: 01/07/2023]
Abstract
It is recognized that d-amphetamine (AMPH)-induced hyperactivity is thought to be a valid animal model of mania. In the present study, we investigated whether a proinflammatory oxidative gene indoleamine-2,3-dioxygenase (IDO) is involved in AMPH-induced mitochondrial burden, and whether mood stabilizers (i.e., lithium and valproate) modulate IDO to protect against AMPH-induced mania-like behaviors. AMPH-induced IDO-1 expression was significantly greater than IDO-2 expression in the prefrontal cortex of wild type mice. IDO-1 expression was more pronounced in the mitochondria than in the cytosol. AMPH treatment activated intra-mitochondrial Ca2+ accumulation and mitochondrial oxidative burden, while inhibited mitochondrial membrane potential and activity of the mitochondrial complex (I > II), mitochondrial glutathione peroxidase, and superoxide dismutase, indicating that mitochondrial burden might be contributable to mania-like behaviors induced by AMPH. The behaviors were significantly attenuated by lithium, valproate, or IDO-1 knockout, but not in IDO-2 knockout mice. Lithium, valproate administration, or IDO-1 knockout significantly attenuated mitochondrial burden. Neither lithium nor valproate produced additive effects above the protective effects observed in IDO-1 KO in mice. Collectively, our results suggest that mood stabilizers attenuate AMPH-induced mania-like behaviors via attenuation of IDO-1-dependent mitochondrial stress, highlighting IDO-1 as a novel molecular target for the protective potential of mood stabilizers.
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Affiliation(s)
- Hai-Quyen Tran
- Neuropsychopharmacology and Toxicology Program, BK21 PLUS Project, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Eun-Joo Shin
- Neuropsychopharmacology and Toxicology Program, BK21 PLUS Project, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Kuniaki Saito
- Advanced Diagnostic System Research Laboratory, Fujita Health University Graduate School of Health Sciences, Toyoake, Japan.
| | - The-Vinh Tran
- Neuropsychopharmacology and Toxicology Program, BK21 PLUS Project, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Dieu-Hien Phan
- Neuropsychopharmacology and Toxicology Program, BK21 PLUS Project, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Naveen Sharma
- Neuropsychopharmacology and Toxicology Program, BK21 PLUS Project, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea
| | - Dae-Won Kim
- Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Gangneung-Wonju National University, Gangneung, 25457, South Korea
| | - Soo Young Choi
- Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chunchon, 24252, Republic of Korea
| | - Ji Hoon Jeong
- Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul, Republic of Korea
| | - Choon-Gon Jang
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, Suwon, South Korea
| | - Jae Hoon Cheong
- Department of Pharmacy, Sahmyook University, 815 Hwarangro, Nowon-gu, Seoul, 01795, Republic of Korea
| | - Toshitaka Nabeshima
- Advanced Diagnostic System Research Laboratory, Fujita Health University Graduate School of Health Sciences, Toyoake, Japan; Japanese Drug Organization of Appropriate Use and Research, Nagoya, Japan
| | - Hyoung-Chun Kim
- Neuropsychopharmacology and Toxicology Program, BK21 PLUS Project, College of Pharmacy, Kangwon National University, Chunchon, 24341, Republic of Korea.
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11
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Investigating KYNA production and kynurenergic manipulation on acute mouse brain slice preparations. Brain Res Bull 2019; 146:185-191. [DOI: 10.1016/j.brainresbull.2018.12.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 11/19/2018] [Accepted: 12/26/2018] [Indexed: 01/09/2023]
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12
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Zakrocka I, Targowska-Duda KM, Wnorowski A, Kocki T, Jóźwiak K, Turski WA. Influence of Cyclooxygenase-2 Inhibitors on Kynurenic Acid Production in Rat Brain in Vitro. Neurotox Res 2019; 35:244-254. [PMID: 30178287 PMCID: PMC6313367 DOI: 10.1007/s12640-018-9952-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 08/09/2018] [Accepted: 08/22/2018] [Indexed: 12/11/2022]
Abstract
Significant body of evidence suggests that abnormal kynurenic acid (KYNA) level is involved in the pathophysiology of central nervous system disorders. In the brain, KYNA is synthesized from kynurenine (KYN) by kynurenine aminotransferases (KATs), predominantly by KAT II isoenzyme. Blockage of ionotropic glutamate (GLU) receptors is a main cellular effect of KYNA. High KYNA levels have been linked with psychotic symptoms and cognitive dysfunction in animals and humans. As immunological imbalance and impaired glutamatergic neurotransmission are one of the crucial processes in neurological pathologies, we aimed to analyze the effect of anti-inflammatory agents, inhibitors of cyclooxygenase-2 (COX-2): celecoxib, niflumic acid, and parecoxib, on KYNA synthesis and KAT II activity in rat brain in vitro. The influence of COX-2 inhibitors was examined in rat brain cortical slices and on isolated KAT II enzyme. Niflumic acid and parecoxib decreased in a dose-dependent manner KYNA production and KAT II activity in rat brain cortex in vitro, whereas celecoxib was ineffective. Molecular docking results suggested that niflumic acid and parecoxib interact with an active site of KAT II. In conclusion, niflumic acid and parecoxib are dual COX-2 and KAT II inhibitors.
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Affiliation(s)
- Izabela Zakrocka
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego 8b, 20-090, Lublin, Poland.
| | | | - Artur Wnorowski
- Department of Biopharmacy, Medical University of Lublin, Chodźki 4a, 20-093, Lublin, Poland
| | - Tomasz Kocki
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego 8b, 20-090, Lublin, Poland
| | - Krzysztof Jóźwiak
- Department of Biopharmacy, Medical University of Lublin, Chodźki 4a, 20-093, Lublin, Poland
| | - Waldemar A Turski
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego 8b, 20-090, Lublin, Poland
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13
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Tufvesson-Alm M, Schwieler L, Schwarcz R, Goiny M, Erhardt S, Engberg G. Importance of kynurenine 3-monooxygenase for spontaneous firing and pharmacological responses of midbrain dopamine neurons: Relevance for schizophrenia. Neuropharmacology 2018; 138:130-139. [PMID: 29879409 DOI: 10.1016/j.neuropharm.2018.06.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 06/01/2018] [Accepted: 06/03/2018] [Indexed: 12/15/2022]
Abstract
Kynurenine 3-monooxygenase (KMO) is an essential enzyme of the kynurenine pathway, converting kynurenine into 3-hydroxykynurenine. Inhibition of KMO increases kynurenine, resulting in elevated levels of kynurenic acid (KYNA), an endogenous N-methyl-d-aspartate and α*7-nicotinic receptor antagonist. The concentration of KYNA is elevated in the brain of patients with schizophrenia, possibly as a result of a reduced KMO activity. In the present study, using in vivo single cell recording techniques, we investigated the electrophysiological characteristics of ventral tegmental area dopamine (VTA DA) neurons and their response to antipsychotic drugs in a KMO knock-out (K/O) mouse model. KMO K/O mice exhibited a marked increase in spontaneous VTA DA neuron activity as compared to wild-type (WT) mice. Furthermore, VTA DA neurons showed clear-cut, yet qualitatively opposite, responses to the antipsychotic drugs haloperidol and clozapine in the two genotypes. The anti-inflammatory drug parecoxib successfully lowered the firing activity of VTA DA neurons in KMO K/O, but not in WT mice. Minocycline, an antibiotic and anti-inflammatory drug, produced no effect in this regard. Taken together, the present data further support the usefulness of KMO K/O mice for studying distinct aspects of the pathophysiology and pharmacological treatment of psychiatric disorders such as schizophrenia.
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Affiliation(s)
| | - Lilly Schwieler
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
| | - Robert Schwarcz
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Michel Goiny
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
| | - Sophie Erhardt
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
| | - Göran Engberg
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden; Department of Physiology and Pharmacology, Karolinska Institute, Biomedicum 5C, 171 77, Stockholm, Sweden.
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14
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Holmberg D, Franzén-Röhl E, Idro R, Opoka RO, Bangirana P, Sellgren CM, Wickström R, Färnert A, Schwieler L, Engberg G, John CC. Cerebrospinal fluid kynurenine and kynurenic acid concentrations are associated with coma duration and long-term neurocognitive impairment in Ugandan children with cerebral malaria. Malar J 2017; 16:303. [PMID: 28754152 PMCID: PMC5534063 DOI: 10.1186/s12936-017-1954-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 07/22/2017] [Indexed: 01/26/2023] Open
Abstract
Background One-fourth of children with cerebral malaria (CM) retain cognitive sequelae up to 2 years after acute disease. The kynurenine pathway of the brain, forming neuroactive metabolites, e.g. the NMDA-receptor antagonist kynurenic acid (KYNA), has been implicated in long-term cognitive dysfunction in other CNS infections. In the present study, the association between the kynurenine pathway and neurologic/cognitive complications in children with CM was investigated. Methods Cerebrospinal fluid (CSF) concentrations of KYNA and its precursor kynurenine in 69 Ugandan children admitted for CM to Mulago Hospital, Kampala, Uganda, between 2008 and 2013 were assessed. CSF kynurenine and KYNA were compared to CSF cytokine levels, acute and long-term neurologic complications, and long-term cognitive impairments. CSF kynurenine and KYNA from eight Swedish children without neurological or infectious disease admitted to Astrid Lindgren’s Children’s Hospital were quantified and used for comparison. Results Children with CM had significantly higher CSF concentration of kynurenine and KYNA than Swedish children (P < 0.0001 for both), and CSF kynurenine and KYNA were positively correlated. In children with CM, CSF kynurenine and KYNA concentrations were associated with coma duration in children of all ages (P = 0.003 and 0.04, respectively), and CSF kynurenine concentrations were associated with worse overall cognition (P = 0.056) and attention (P = 0.003) at 12-month follow-up in children ≥5 years old. Conclusions CSF KYNA and kynurenine are elevated in children with CM, indicating an inhibition of glutamatergic and cholinergic signaling. This inhibition may lead acutely to prolonged coma and long-term to impairment of attention and cognition.
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Affiliation(s)
- Dag Holmberg
- Department of Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Department of Medicine Solna, Unit of Infectious Diseases, Karolinska Institutet, Stockholm, Sweden
| | - Elisabeth Franzén-Röhl
- Department of Medicine Solna, Unit of Infectious Diseases, Karolinska Institutet, Stockholm, Sweden.,Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Richard Idro
- Department of Paediatrics and Child Health, Makerere University, Kampala, Uganda
| | - Robert O Opoka
- Department of Paediatrics and Child Health, Makerere University, Kampala, Uganda
| | - Paul Bangirana
- Department of Psychiatry, Makerere University, Kampala, Uganda
| | - Carl M Sellgren
- Department of Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Ronny Wickström
- Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - Anna Färnert
- Department of Medicine Solna, Unit of Infectious Diseases, Karolinska Institutet, Stockholm, Sweden.,Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Lilly Schwieler
- Department of Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Göran Engberg
- Department of Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden.
| | - Chandy C John
- Department of Pediatrics, Indiana University, Indianapolis, IN, USA.,Department of Pediatrics, University of Minnesota, Minnesota, USA
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15
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Zakrocka I, Targowska-Duda KM, Wnorowski A, Kocki T, Jóźwiak K, Turski WA. Angiotensin II Type 1 Receptor Blockers Inhibit KAT II Activity in the Brain-Its Possible Clinical Applications. Neurotox Res 2017; 32:639-648. [PMID: 28733707 PMCID: PMC5602025 DOI: 10.1007/s12640-017-9781-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 06/28/2017] [Accepted: 07/05/2017] [Indexed: 01/13/2023]
Abstract
Angiotensin II receptor blockers (ARBs) are one of the most frequently recommended antihypertensive drugs. Apart from their activity towards the circulatory system, ARBs also penetrate the blood-brain barrier and display neuroprotective effects. Kynurenic acid (KYNA) is an endogenous metabolite of tryptophan produced by kynurenine aminotransferase II (KAT II) in the brain. Antagonism towards all ionotropic glutamate (GLU) receptors is the main mechanism of KYNA action. An elevated brain level of KYNA is linked with memory impairment and psychotic symptoms. The aim of this study was to examine the influence of three ARBs: irbesartan, losartan, and telmisartan on KYNA production and KAT II activity in rat brain. The effect of ARBs on KYNA production was analyzed in rat brain cortical slices and on isolated KAT II enzyme. Irbesartan, losartan, and telmisartan decreased KYNA production and KAT II activity in a dose-dependent manner in rat brain cortex in vitro. Molecular docking suggested that the examined ARBs could bind to an active site of KAT II. In conclusion, ARBs decrease KYNA production in rat brain by direct inhibition of KAT II enzymatic activity. This novel mechanism of ARBs action may be advantageous in the treatment of cognitive impairment or the management of schizophrenia.
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Affiliation(s)
- Izabela Zakrocka
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego 8b, 20-090, Lublin, Poland.
| | | | - Artur Wnorowski
- Department of Biopharmacy, Medical University of Lublin, Chodźki 4a, 20-093 Lublin, Poland
| | - Tomasz Kocki
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego 8b, 20-090, Lublin, Poland
| | - Krzysztof Jóźwiak
- Department of Biopharmacy, Medical University of Lublin, Chodźki 4a, 20-093 Lublin, Poland
| | - Waldemar A Turski
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego 8b, 20-090, Lublin, Poland
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16
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Plitman E, Iwata Y, Caravaggio F, Nakajima S, Chung JK, Gerretsen P, Kim J, Takeuchi H, Chakravarty MM, Remington G, Graff-Guerrero A. Kynurenic Acid in Schizophrenia: A Systematic Review and Meta-analysis. Schizophr Bull 2017; 43:764-777. [PMID: 28187219 PMCID: PMC5472151 DOI: 10.1093/schbul/sbw221] [Citation(s) in RCA: 132] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Kynurenic acid (KYNA) is an endogenous antagonist of N-methyl-D-aspartate and α7 nicotinic acetylcholine receptors that is derived from astrocytes as part of the kynurenine pathway of tryptophan degradation. Evidence suggests that abnormal KYNA levels are involved in the pathophysiology of schizophrenia. However, this has never been assessed through a meta-analysis. A literature search was conducted through Ovid using Embase, Medline, and PsycINFO databases (last search: December 2016) with the search terms: (kynuren* or KYNA) and (schizophreni* or psychosis). English language studies measuring KYNA levels using any method in patients with schizophrenia and healthy controls (HCs) were identified. Standardized mean differences (SMDs) were calculated to determine differences in KYNA levels between groups. Subgroup analyses were separately performed for nonoverlapping participant samples, KYNA measurement techniques, and KYNA sample source. The influences of patients' age, antipsychotic status (%medicated), and sex (%male) on study SMDs were assessed through a meta-regression. Thirteen studies were deemed eligible for inclusion in the meta-analysis. In the main analysis, KYNA levels were elevated in the patient group. Subgroup analyses demonstrated that KYNA levels were increased in nonoverlapping participant samples, and centrally (cerebrospinal fluid and brain tissue) but not peripherally. Patients' age, %medicated, and %male were each positively associated with study SMDs. Overall, KYNA levels are increased in patients with schizophrenia, specifically within the central nervous system. An improved understanding of KYNA in patients with schizophrenia may contribute to the development of novel diagnostic approaches and therapeutic strategies.
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Affiliation(s)
- Eric Plitman
- Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada;,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Yusuke Iwata
- Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Fernando Caravaggio
- Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Shinichiro Nakajima
- Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada;,Department of Psychiatry, University of Toronto, Toronto, ON, Canada;,Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, ON, Canada;,Department of Neuropsychiatry, Keio University, Tokyo, Japan
| | - Jun Ku Chung
- Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada;,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Philip Gerretsen
- Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada;,Department of Psychiatry, University of Toronto, Toronto, ON, Canada;,Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Julia Kim
- Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada;,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Hiroyoshi Takeuchi
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada;,Department of Neuropsychiatry, Keio University, Tokyo, Japan;,Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - M. Mallar Chakravarty
- Cerebral Imaging Centre, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada;,Departments of Psychiatry and Biomedical Engineering, McGill University, Montreal, QC, Canada
| | - Gary Remington
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada;,Department of Psychiatry, University of Toronto, Toronto, ON, Canada;,Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, ON, Canada;,Campbell Institute Research Program, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Ariel Graff-Guerrero
- Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada;,Institute of Medical Science, University of Toronto, Toronto, ON, Canada;,Department of Psychiatry, University of Toronto, Toronto, ON, Canada;,Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, ON, Canada;,Campbell Institute Research Program, Centre for Addiction and Mental Health, Toronto, ON, Canada
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17
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The kynurenine pathway in schizophrenia and bipolar disorder. Neuropharmacology 2017; 112:297-306. [DOI: 10.1016/j.neuropharm.2016.05.020] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 05/26/2016] [Accepted: 05/27/2016] [Indexed: 11/20/2022]
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18
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Inhibition of kynurenine aminotransferase II reduces activity of midbrain dopamine neurons. Neuropharmacology 2016; 102:42-7. [DOI: 10.1016/j.neuropharm.2015.10.028] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 10/20/2015] [Accepted: 10/22/2015] [Indexed: 01/25/2023]
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19
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DeAngeli NE, Todd TP, Chang SE, Yeh HH, Yeh PW, Bucci DJ. Exposure to Kynurenic Acid during Adolescence Increases Sign-Tracking and Impairs Long-Term Potentiation in Adulthood. Front Behav Neurosci 2015; 8:451. [PMID: 25610382 PMCID: PMC4285091 DOI: 10.3389/fnbeh.2014.00451] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 12/16/2014] [Indexed: 11/21/2022] Open
Abstract
Changes in brain reward systems are thought to contribute significantly to the cognitive and behavioral impairments of schizophrenia, as well as the propensity to develop co-occurring substance abuse disorders. Presently, there are few treatments for persons with a dual diagnosis and little is known about the neural substrates that underlie co-occurring schizophrenia and substance abuse. One goal of the present study was to determine if a change in the concentration of kynurenic acid (KYNA), a tryptophan metabolite that is increased in the brains of people with schizophrenia, affects reward-related behavior. KYNA is an endogenous antagonist of NMDA glutamate receptors and α7 nicotinic acetylcholine receptors, both of which are critically involved in neurodevelopment, plasticity, and behavior. In Experiment 1, rats were treated throughout adolescence with L-kynurenine (L-KYN), the precursor of KYNA. As adults, the rats were tested drug-free in an autoshaping procedure in which a lever was paired with food. Rats treated with L-KYN during adolescence exhibited increased sign-tracking behavior (lever pressing) when they were tested as adults. Sign-tracking is thought to reflect the lever acquiring incentive salience (motivational value) as a result of its pairing with reward. Thus, KYNA exposure may increase the incentive salience of cues associated with reward, perhaps contributing to an increase in sensitivity to drug-related cues in persons with schizophrenia. In Experiment 2, we tested the effects of exposure to KYNA during adolescence on hippocampal long-term potentiation (LTP). Rats treated with L-KYN exhibited no LTP after a burst of high-frequency stimulation that was sufficient to produce robust LTP in vehicle-treated rats. This finding represents the first demonstrated consequence of elevated KYNA concentration during development and provides insight into the basis for cognitive and behavioral deficits that result from exposure to KYNA during adolescence.
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Affiliation(s)
- Nicole E DeAngeli
- Department of Psychological and Brain Sciences, Dartmouth College , Hanover, NH , USA
| | - Travis P Todd
- Department of Psychological and Brain Sciences, Dartmouth College , Hanover, NH , USA
| | - Stephen E Chang
- Department of Psychological and Brain Sciences, Dartmouth College , Hanover, NH , USA
| | - Hermes H Yeh
- Department of Physiology and Neurobiology, Geisel School of Medicine, Dartmouth College , Hanover, NH , USA
| | - Pamela W Yeh
- Department of Physiology and Neurobiology, Geisel School of Medicine, Dartmouth College , Hanover, NH , USA
| | - David J Bucci
- Department of Psychological and Brain Sciences, Dartmouth College , Hanover, NH , USA
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20
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Bay-Richter C, Linderholm KR, Lim CK, Samuelsson M, Träskman-Bendz L, Guillemin GJ, Erhardt S, Brundin L. A role for inflammatory metabolites as modulators of the glutamate N-methyl-D-aspartate receptor in depression and suicidality. Brain Behav Immun 2015; 43:110-7. [PMID: 25124710 DOI: 10.1016/j.bbi.2014.07.012] [Citation(s) in RCA: 203] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 07/16/2014] [Accepted: 07/25/2014] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Patients with depression and suicidality suffer from low-grade neuroinflammation. Pro-inflammatory cytokines activate indoleamine 2,3-dioxygenase, an initial enzyme of the kynurenine pathway. This pathway produces neuroactive metabolites, including quinolinic- and kynurenic acid, binding to the glutamate N-methyl-d-aspartate-receptor, which is hypothesized to be part of the neural mechanisms underlying symptoms of depression. We therefore hypothesized that symptoms of depression and suicidality would fluctuate over time in patients prone to suicidal behavior, depending on the degree of inflammation and kynurenine metabolite levels in the cerebrospinal fluid (CSF). METHODS We measured cytokines and kynurenine metabolites in CSF, collected from suicide attempters at repeated occasions over 2 years (total patient samples n=143, individuals n=30) and healthy controls (n=36). The association between the markers and psychiatric symptoms was assessed using the Montgomery Asberg Depression Rating Scale and the Suicide Assessment Scale. RESULTS Quinolinic acid was increased and kynurenic acid decreased over time in suicidal patients versus healthy controls. Furthermore, we found a significant association between low kynurenic acid and severe depressive symptoms, as well as between high interleukin-6 levels and more severe suicidal symptoms. CONCLUSIONS We demonstrate a long-term dysregulation of the kynurenine pathway in the central nervous system of suicide attempters. An increased load of inflammatory cytokines was coupled to more severe symptoms. We therefore suggest that patients with a dysregulated kynurenine pathway are vulnerable to develop depressive symptoms upon inflammatory conditions, as a result the excess production of the NMDA-receptor agonist quinolinic acid. This study provides a neurobiological framework supporting the use of NMDA-receptor antagonists in the treatment of suicidality and depression.
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Affiliation(s)
- Cecilie Bay-Richter
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Risskov, Denmark.
| | - Klas R Linderholm
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
| | - Chai K Lim
- Neuroinflammation Group, Australian School of Advanced Medicine, Macquarie University, NSW, Australia
| | - Martin Samuelsson
- Faculty of Health Sciences, Department of Clinical and Experimental Medicine, Division of Psychiatry, Linköping University, Linköping, Sweden
| | - Lil Träskman-Bendz
- Department of Clinical Sciences, Section of Psychiatry, Lund University, Lund, Sweden
| | - Gilles J Guillemin
- Neuroinflammation Group, Australian School of Advanced Medicine, Macquarie University, NSW, Australia
| | - Sophie Erhardt
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
| | - Lena Brundin
- Division of Psychiatry and Behavioral Medicine, Michigan State University, Grand Rapids, MI, USA; Laboratory of Behavioral Medicine, Van Andel Research Institute, Grand Rapids, MI, USA
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21
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Sellgren CM, Kegel ME, Bergen SE, Ekman CJ, Olsson S, Larsson M, Vawter MP, Backlund L, Sullivan PF, Sklar P, Smoller JW, Magnusson PKE, Hultman CM, Walther-Jallow L, Svensson CI, Lichtenstein P, Schalling M, Engberg G, Erhardt S, Landén M. The KMO allele encoding Arg452 is associated with psychotic features in bipolar disorder type 1, and with increased CSF KYNA level and reduced KMO expression. Mol Psychiatry 2014; 19:334-41. [PMID: 23459468 PMCID: PMC4990004 DOI: 10.1038/mp.2013.11] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 11/24/2012] [Accepted: 01/02/2013] [Indexed: 12/15/2022]
Abstract
The kynurenine pathway metabolite kynurenic acid (KYNA), modulating glutamatergic and cholinergic neurotransmission, is increased in cerebrospinal fluid (CSF) of patients with schizophrenia or bipolar disorder type 1 with psychotic features. KYNA production is critically dependent on kynurenine 3-monooxygenase (KMO). KMO mRNA levels and activity in prefrontal cortex (PFC) are reduced in schizophrenia. We hypothesized that KMO expression in PFC would be reduced in bipolar disorder with psychotic features and that a functional genetic variant of KMO would associate with this disease, CSF KYNA level and KMO expression. KMO mRNA levels were reduced in PFC of bipolar disorder patients with lifetime psychotic features (P=0.005, n=19) or schizophrenia (P=0.02, n=36) compared with nonpsychotic patients and controls. KMO genetic association to psychotic features in bipolar disorder type 1 was studied in 493 patients and 1044 controls from Sweden. The KMO Arg(452) allele was associated with psychotic features during manic episodes (P=0.003). KMO Arg(452) was studied for association to CSF KYNA levels in an independent sample of 55 Swedish patients, and to KMO expression in 717 lymphoblastoid cell lines and 138 hippocampal biopsies. KMO Arg(452) associated with increased levels of CSF KYNA (P=0.03) and reduced lymphoblastoid and hippocampal KMO expression (P≤0.05). Thus, findings from five independent cohorts suggest that genetic variation in KMO influences the risk for psychotic features in mania of bipolar disorder patients. This provides a possible mechanism for the previous findings of elevated CSF KYNA levels in those bipolar patients with lifetime psychotic features and positive association between KYNA levels and number of manic episodes.
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Affiliation(s)
- CM Sellgren
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden,Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - ME Kegel
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - SE Bergen
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - CJ Ekman
- Section of Psychiatry, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - S Olsson
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - M Larsson
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - MP Vawter
- Functional Genomics Laboratory, Department of Psychiatry and Human Behavior, University of California Irvine School of Medicine, Irvine, CA, USA
| | - L Backlund
- Neurogenetics Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden,Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - PF Sullivan
- Department of Genetic and Psychiatry, University of North Carolina, Chapel Hill, NC, USA
| | - P Sklar
- Division of Psychiatric Genomics, Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - JW Smoller
- Psychiatric and Neurodevelopmental Genetics Unit, Center for Human Genetics, Research, Massachusetts General Hospital, Boston, MA, USA,Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - PKE Magnusson
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - CM Hultman
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - L Walther-Jallow
- Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - CI Svensson
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - P Lichtenstein
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - M Schalling
- Neurogenetics Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden,Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - G Engberg
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - S Erhardt
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - M Landén
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden,The Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
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22
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Campbell BM, Charych E, Lee AW, Möller T. Kynurenines in CNS disease: regulation by inflammatory cytokines. Front Neurosci 2014; 8:12. [PMID: 24567701 PMCID: PMC3915289 DOI: 10.3389/fnins.2014.00012] [Citation(s) in RCA: 250] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 01/20/2014] [Indexed: 12/27/2022] Open
Abstract
The kynurenine pathway (KP) metabolizes the essential amino acid tryptophan and generates a number of neuroactive metabolites collectively called the kynurenines. Segregated into at least two distinct branches, often termed the “neurotoxic” and “neuroprotective” arms of the KP, they are regulated by the two enzymes kynurenine 3-monooxygenase and kynurenine aminotransferase, respectively. Interestingly, several enzymes in the pathway are under tight control of inflammatory mediators. Recent years have seen a tremendous increase in our understanding of neuroinflammation in CNS disease. This review will focus on the regulation of the KP by inflammatory mediators as it pertains to neurodegenerative and psychiatric disorders.
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Affiliation(s)
- Brian M Campbell
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Paramus, NJ, USA
| | - Erik Charych
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Paramus, NJ, USA
| | - Anna W Lee
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Paramus, NJ, USA
| | - Thomas Möller
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Paramus, NJ, USA
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23
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Sanchez-Guajardo V, Barnum C, Tansey M, Romero-Ramos M. Neuroimmunological processes in Parkinson's disease and their relation to α-synuclein: microglia as the referee between neuronal processes and peripheral immunity. ASN Neuro 2013; 5:113-39. [PMID: 23506036 PMCID: PMC3639751 DOI: 10.1042/an20120066] [Citation(s) in RCA: 171] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 03/15/2013] [Accepted: 03/19/2013] [Indexed: 12/15/2022] Open
Abstract
The role of neuroinflammation and the adaptive immune system in PD (Parkinson's disease) has been the subject of intense investigation in recent years, both in animal models of parkinsonism and in post-mortem PD brains. However, how these processes relate to and modulate α-syn (α-synuclein) pathology and microglia activation is still poorly understood. Specifically, how the peripheral immune system interacts, regulates and/or is induced by neuroinflammatory processes taking place during PD is still undetermined. We present herein a comprehensive review of the features and impact that neuroinflamation has on neurodegeneration in different animal models of nigral cell death, how this neuroinflammation relates to microglia activation and the way microglia respond to α-syn in vivo. We also discuss a possible role for the peripheral immune system in animal models of parkinsonism, how these findings relate to the state of microglia activation observed in these animal models and how these findings compare with what has been observed in humans with PD. Together, the available data points to the need for development of dual therapeutic strategies that modulate microglia activation to change not only the way microglia interact with the peripheral immune system, but also to modulate the manner in which microglia respond to encounters with α-syn. Lastly, we discuss the immune-modulatory strategies currently under investigation in animal models of parkinsonism and the degree to which one might expect their outcomes to translate faithfully to a clinical setting.
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Key Words
- lymphocytes
- m1/m2 phenotype
- microglia
- neuroinflammation
- parkinson’s disease
- α-synuclein
- 6-ohda, 6-hydroxydopamine
- ad, alzheimer’s disease
- apc, antigen-presenting cell
- α-syn, α-synuclein
- bbb, brain–blood barrier
- bcg, bacille calmette–guérin
- bm, bone marrow
- cfa, complete freund’s adjuvant
- cm, conditioned media
- cns, central nervous system
- cox, cyclooxygenase
- cr, complement receptor
- csf, cerebrospinal fluid
- da, dopamine
- eae, experimental autoimmune encephalomyelitis
- ga, galatiramer acetate
- gdnf, glial-derived neurotrophic factor
- gfp, green fluorescent protein
- hla-dr, human leucocyte antigen type dr
- ifnγ, interferon γ
- igg, immunoglobulin g
- il, interleukin
- inos, inducible nitric oxide synthase
- lamp, lysosome-associated membrane protein
- lb, lewy body
- lps, lipopolysaccharide
- mhc, major histocompatibility complex
- mptp, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine
- nfκb, nuclear factor κb
- nk, natural killer
- no, nitric oxide
- pd, parkinson’s disease
- pet, positron-emission tomography
- prp, prion protein
- raav, recombinant adeno-associated virus
- rns, reactive nitrogen species
- ros, reactive oxygen species
- sn, substantia nigra
- snp, single nucleotide polymorphism
- tcr, t-cell receptor
- tgfβ, tumour growth factor β
- th, tyrosine hydroxylase
- th1, t helper 1
- tlr, toll-like receptor
- tnf, tumour necrosis factor
- treg, regulatory t-cell
- vip, vasoactive intestinal peptide
- wt, wild-type
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Affiliation(s)
- Vanesa Sanchez-Guajardo
- *CNS Disease Modeling Group, Department of Biomedicine, Ole Worms Allé 3,
Aarhus University, DK-8000 Aarhus C, Denmark
| | - Christopher J. Barnum
- †Department of Physiology, Emory University, School of Medicine, Atlanta, GA
30233, U.S.A
| | - Malú G. Tansey
- †Department of Physiology, Emory University, School of Medicine, Atlanta, GA
30233, U.S.A
| | - Marina Romero-Ramos
- *CNS Disease Modeling Group, Department of Biomedicine, Ole Worms Allé 3,
Aarhus University, DK-8000 Aarhus C, Denmark
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Olsson SK, Sellgren C, Engberg G, Landén M, Erhardt S. Cerebrospinal fluid kynurenic acid is associated with manic and psychotic features in patients with bipolar I disorder. Bipolar Disord 2012; 14:719-26. [PMID: 23030601 DOI: 10.1111/bdi.12009] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVES Kynurenic acid (KYNA), an end metabolite of tryptophan degradation, antagonizes glutamatergic and cholinergic receptors in the brain. Recently, we reported elevated levels of cerebrospinal fluid (CSF) KYNA in male patients with bipolar disorder. Here, we investigate the relationship between symptomatology and the concentration of CSF KYNA in patients with bipolar I disorder. METHODS CSF KYNA levels from euthymic male {n = 21; mean age: 41 years [standard deviation (SD) = 14]} and female [n = 34; mean age: 37 years (SD = 14)] patients diagnosed with bipolar I disorder were analyzed using high-performance liquid chromatography (HPLC). RESULTS Euthymic bipolar I disorder patients with a lifetime occurrence of psychotic features had higher CSF levels of KYNA {2.0 nm [standard error of the mean (SEM) = 0.2]; n = 43} compared to patients without any history of psychotic features [1.3 nm (SEM = 0.2); n = 12] (p = 0.01). Logistic regression, with age as covariate, similarly showed an association between a history of psychotic features and CSF KYNA levels [n = 55; odds ratio (OR) = 4.9, p = 0.03]. Further, having had a recent manic episode (within the previous year) was also associated with CSF KYNA adjusted for age (n = 34; OR = 4.4, p = 0.03), and the association remained significant when adjusting for a lifetime history of psychotic features (OR = 4.1, p = 0.05). CONCLUSIONS Although the causality needs to be determined, the ability of KYNA to influence dopamine transmission and behavior, along with previous reports showing increased brain levels of the compound in patients with schizophrenia and bipolar disorder, may indicate a possible pathophysiological role of KYNA in the development of manic or psychotic symptoms.
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Affiliation(s)
- Sara K Olsson
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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Holtze M, Mickiené A, Atlas A, Lindquist L, Schwieler L. Elevated cerebrospinal fluid kynurenic acid levels in patients with tick-borne encephalitis. J Intern Med 2012; 272:394-401. [PMID: 22443218 DOI: 10.1111/j.1365-2796.2012.02539.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Kynurenic acid (KYNA) is a neuroactive metabolite of tryptophan that is thought to regulate cognitive functions. Previous studies have shown that levels of KYNA increase during virus infection and that this metabolite interacts with the immune system. OBJECTIVE The aim of the study was to investigate whether patients with tick-borne encephalitis (TBE), a viral infectious disease associated with long-term cognitive impairment, have increased levels of KYNA in the cerebrospinal fluid (CSF). METHODS CSF KYNA was analysed using high-performance liquid chromatography in 108 patients with TBE and 52 age-matched controls. Patients were classified according to the severity of TBE: mild (47%), moderate (44%) or severe (9%). RESULTS Concentrations of CSF KYNA were considerably higher in patients with TBE (5.3 nmol L(-1) ) than in control subjects (0.99 nmol L(-1) ). KYNA concentration in the CSF varied greatly amongst individuals with TBE and increased (P < 0.05) with the severity of disease. CONCLUSIONS This is the first study to demonstrate increased levels of CSF KYNA in patients with TBE. The importance of brain KYNA in both immune modulation and neurotransmission raises the possibility that abnormal levels of the compound in TBE might play a part in the pathophysiology of the disease. A detailed knowledge of endogenous brain KYNA during the course of CNS infection might yield further insights into the neuroimmunological role of the compound and may also provide new pharmacological approaches for the treatment of cognitive symptoms.
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Affiliation(s)
- M Holtze
- Department of Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden
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Potential of D-cycloserine in the treatment of behavioral and neuroinflammatory disorders in Parkinson's disease and studies that need to be performed before clinical trials. Kaohsiung J Med Sci 2012; 28:407-17. [DOI: 10.1016/j.kjms.2012.02.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 10/03/2011] [Indexed: 01/20/2023] Open
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Akagbosu CO, Evans GC, Gulick D, Suckow RF, Bucci DJ. Exposure to kynurenic acid during adolescence produces memory deficits in adulthood. Schizophr Bull 2012; 38:769-78. [PMID: 21172906 PMCID: PMC3577048 DOI: 10.1093/schbul/sbq151] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The glia-derived molecule kynurenic acid (KYNA) is an antagonist of α7 nicotinic acetylcholine receptors and the glycine(B) binding site on n-methyl-d-aspartateglutamate receptors, both of which have critical roles in neural plasticity as well as learning and memory. KYNA levels are increased in the brains and cerebral spinal fluid of persons with schizophrenia, leading to the notion that changes in KYNA concentration might contribute to cognitive dysfunction associated with this disorder. Indeed, recent studies indicate that increasing endogenous KYNA concentration by administering l-kynurenine (L-KYN, the precursor of KYNA) impairs spatial as well as contextual learning and memory in adult rats. In the present study, rats were treated with L-KYN (100 mg/kg) throughout adolescence to increase endogenous KYNA concentration during this critical time in brain development. Rats were then tested drug-free as adults to test the hypothesis that exposure to elevated levels of KYNA during development may contribute to cognitive dysfunction later in life. Consistent with prior studies in which adult rats were treated acutely with L-KYN, juvenile rats exposed to increased KYNA concentration during adolescence exhibited deficits in contextual fear memory, but cue-specific fear memory was not impaired. In addition, rats treated with L-KYN as adolescents were impaired on a novel object recognition memory task when tested as adults. The memory deficits could not be explained by drug-induced changes in locomotor activity or shock sensitivity. Together, these findings add to the growing literature supporting the notion that exposure to increased concentration of KYNA may contribute to cognitive deficits typically observed in schizophrenia.
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Affiliation(s)
- Cynthia O. Akagbosu
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH
| | - Gretchen C. Evans
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH
| | - Danielle Gulick
- Department of Psychiatry, Dartmouth Medical School, Lebanon, NH
| | | | - David J. Bucci
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH,To whom correspondence should be addressed; tel: 603-646-3439, fax: 603-646-1419, e-mail:
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Linderholm KR, Skogh E, Olsson SK, Dahl ML, Holtze M, Engberg G, Samuelsson M, Erhardt S. Increased levels of kynurenine and kynurenic acid in the CSF of patients with schizophrenia. Schizophr Bull 2012; 38:426-32. [PMID: 20729465 PMCID: PMC3329991 DOI: 10.1093/schbul/sbq086] [Citation(s) in RCA: 222] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND The kynurenic acid (KYNA) hypothesis for schizophrenia is partly based on studies showing increased brain levels of KYNA in patients. KYNA is an endogenous metabolite of tryptophan (TRP) produced in astrocytes and antagonizes N-methyl-D-aspartate and α7* nicotinic receptors. METHODS The formation of KYNA is determined by the availability of substrate, and hence, we analyzed KYNA and its precursors, kynurenine (KYN) and TRP, in the cerebrospinal fluid (CSF) of patients with schizophrenia. CSF from male patients with schizophrenia on olanzapine treatment (n = 16) was compared with healthy male volunteers (n = 29). RESULTS KYN and KYNA concentrations were higher in patients with schizophrenia (60.7 ± 4.37 nM and 2.03 ± 0.23 nM, respectively) compared with healthy volunteers (28.6 ± 1.44 nM and 1.36 ± 0.08 nM, respectively), whereas TRP did not differ between the groups. In all subjects, KYN positively correlated to KYNA. CONCLUSION Our results demonstrate increased levels of CSF KYN and KYNA in patients with schizophrenia and further support the hypothesis that KYNA is involved in the pathophysiology of schizophrenia.
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Affiliation(s)
- Klas R. Linderholm
- Department of Physiology and Pharmacology, Nanna Svartz väg 2, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Elisabeth Skogh
- Department of Clinical and Experimental Medicine, Section of Psychiatry, Faculty of Health Sciences, Linköping University, Linköping, Sweden
| | - Sara K. Olsson
- Department of Physiology and Pharmacology, Nanna Svartz väg 2, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Marja-Liisa Dahl
- Department of Medical Sciences, Clinical Pharmacology, Uppsala University, Uppsala, Sweden
- Department of Clinical Pharmacology, Karolinska University Hospital, Stockholm, Sweden
| | - Maria Holtze
- Department of Physiology and Pharmacology, Nanna Svartz väg 2, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Göran Engberg
- Department of Physiology and Pharmacology, Nanna Svartz väg 2, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Martin Samuelsson
- Department of Clinical and Experimental Medicine, Section of Psychiatry, Faculty of Health Sciences, Linköping University, Linköping, Sweden
| | - Sophie Erhardt
- Department of Physiology and Pharmacology, Nanna Svartz väg 2, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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Subchronic elevation of brain kynurenic acid augments amphetamine-induced locomotor response in mice. J Neural Transm (Vienna) 2011; 119:155-63. [PMID: 21904895 DOI: 10.1007/s00702-011-0706-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2011] [Accepted: 08/20/2011] [Indexed: 10/17/2022]
Abstract
The neuromodulating tryptophan metabolite kynurenic acid (KYNA) is increased in the brain of patients with schizophrenia. In the present study we investigate the spontaneous locomotor activity as well as the locomotor response to d-amphetamine [5 mg/kg, administered intraperitoneal (i.p.)] after increasing endogenous levels of brain KYNA in mice by acute (10 mg/kg, i.p., 60 min) or subchronic (100 mg/kg i.p., twice daily for 6 days) pretreatment with the blood-brain crossing precursor, L: -kynurenine. We found that an acute increase in the brain KYNA levels caused increased corner time and percent peripheral activity but did not change the d-amphetamine-induced locomotor response. In contrast, subchronic elevation of KYNA did not change the spontaneous locomotor activity but produced an exaggerated d-amphetamine-induced hyperlocomotion. These results cohere with clinical studies of patients with schizophrenia, where a potentiated DA release associated with exacerbation of positive symptoms has been observed following d-amphetamine administration. Present results further underscore KYNA as a possible mediator of the aberrant dopaminergic neurotransmission seen in schizophrenia.
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Oxenkrug GF. Interferon-gamma-inducible kynurenines/pteridines inflammation cascade: implications for aging and aging-associated psychiatric and medical disorders. J Neural Transm (Vienna) 2011; 118:75-85. [PMID: 20811799 PMCID: PMC3026891 DOI: 10.1007/s00702-010-0475-7] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 08/23/2010] [Indexed: 12/20/2022]
Abstract
This review of literature and our data suggests that up-regulated production of interferon-gamma (IFNG) in periphery and brain triggers a merger of tryptophan (TRY)-kynurenine (KYN) and guanine-tetrahydrobiopterin (BH4) metabolic pathways into inflammation cascade involved in aging and aging-associated medical and psychiatric disorders (AAMPD) (metabolic syndrome, depression, vascular cognitive impairment). IFNG-inducible KYN/pteridines inflammation cascade is characterized by up-regulation of nitric oxide synthase (NOS) activity (induced by KYN) and decreased formation of NOS cofactor, BH4, that results in uncoupling of NOS that shifting arginine from NO to superoxide anion production. Superoxide anion and free radicals among KYN derivatives trigger phospholipase A2-arachidonic acid cascade associated with AAMPD. IFNG-induced up-regulation of indoleamine 2,3-dioxygenase (IDO), rate-limiting enzyme of TRY-KYN pathway, decreases TRY conversion into serotonin (substrate of antidepressant effect) and increases production of KYN associated with diabetes [xanthurenic acid (XA)], anxiety (KYN), psychoses and cognitive impairment (kynurenic acid). IFNG-inducible KYN/pteridines inflammation cascade is impacted by IFNG (+874) T/A genotypes, encoding cytokine production. In addition to literature data on KYN/TRY ratio (IDO activity index), we observe neopterin levels (index of activity of rate-limiting enzyme of guanine-BH4 pathway) to be higher in carriers of high (T) than of low (A) producers alleles; and to correlate with AAMPD markers (e.g., insulin resistance, body mass index, mortality risk), and with IFN-alpha-induced depression in hepatitis C patients. IFNG-inducible cascade is influenced by environmental factors (e.g., vitamin B6 deficiency increases XA formation) and by pharmacological agents; and might offer new approaches for anti-aging and anti-AAMPD interventions.
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Affiliation(s)
- Gregory F Oxenkrug
- Psychiatry and Inflammation Program, Department of Psychiatry, Tufts University/Tufts Medical Center, Boston, MA, USA.
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Olsson SK, Samuelsson M, Saetre P, Lindström L, Jönsson EG, Nordin C, Engberg G, Erhardt S, Landén M. Elevated levels of kynurenic acid in the cerebrospinal fluid of patients with bipolar disorder. J Psychiatry Neurosci 2010; 35:195-9. [PMID: 20420770 PMCID: PMC2861136 DOI: 10.1503/jpn.090180] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Patients with schizophrenia show elevated brain levels of the neuroactive tryptophan metabolite kynurenic acid (KYNA). This astrocyte-derived mediator acts as a neuroprotectant and modulates sensory gating and cognitive function. We measured the levels of KYNA in the cerebrospinal fluid (CSF) of patients with bipolar disorder and healthy volunteers to investigate the putative involvement of KYNA in bipolar disorder. METHODS We obtained CSF by lumbar puncture from 23 healthy men and 31 euthymic men with bipolar disorder. We analyzed the samples using high-performance liquid chromatography. RESULTS Patients with bipolar disorder had increased levels of KYNA in their CSF compared with healthy volunteers (1.71 nM, standard error of the mean [SEM] 0.13 v. 1.13 nM, SEM 0.09; p = 0.002. The levels of KYNA were positively correlated with age among bipolar patients but not healthy volunteers. LIMITATIONS The influence of ongoing drug treatment among patients cannot be ruled out. We conducted our study during the euthymic phase of the disease. CONCLUSION Brain KYNA levels are increased in euthymic men with bipolar disorder. In addition, KYNA levels increased with age in these patients. These findings indicate shared mechanisms between bipolar disorder and schizophrenia. Elevated levels of brain KYNA may provide further insight to the pathophysiology and progression of bipolar disorder.
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Affiliation(s)
| | | | | | | | | | | | | | - Sophie Erhardt
- Correspondence to: Dr. S. Erhardt, Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77 Stockholm, Sweden; fax 46 8 31 06 22;
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Linderholm K, Powell S, Olsson E, Holtze M, Snodgrass R, Erhardt S. Role of the NMDA-receptor in Prepulse Inhibition in the Rat. Int J Tryptophan Res 2010; 3:1-12. [PMID: 22084584 PMCID: PMC3195246 DOI: 10.4137/ijtr.s4260] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Kynurenic acid (KYNA) is an endogenous metabolite of tryptophan. Studies have revealed increased brain KYNA levels in patients with schizophrenia. Prepulse inhibition (PPI) is a behavioral model for sensorimotor gating and found to be reduced in schizophrenia. Previous studies have shown that pharmacologically elevated brain KYNA levels disrupt PPI in the rat. The aim of the present study was to investigate the receptor(s) involved in this effect. Rats were treated with different drugs selectively blocking each of the sites that KYNA antagonizes, namely the glutamate recognition site of the N-methyl-D-aspartate receptor (NMDAR), the α7* nicotinic acetylcholine receptor (α7nAChR) and the glycine site of the NMDAR. Kynurenine (200 mg/kg) was given to replicate the effects of increased levels of KYNA on PPI. In order to block the glutamate recognition site of the NMDAR, CGS 19755 (10 mg/kg) or SDZ 220–581 (2.5 mg/kg) were administered and to antagonize the α7nAChR methyllycaconitine (MLA; 6 mg/kg) was given. L-701,324 (1 and 4 mg/kg) or 4-Chloro-kynurenine (4-Cl-KYN; 25, 50 and 100 mg/kg), a drug in situ converted to 7-Chloro-kynurenic acid, were used to block the glycine-site of the NMDAR. Administration of SDZ 220-581 or CGS 19755 was associated with a robust reduction in PPI, whereas L-701,324, 4-Cl-KYN or MLA failed to alter PPI. Kynurenine increased brain KYNA levels 5-fold and tended to decrease PPI. The present study suggests that neither antagonism of the glycine-site of the NMDA receptor nor antagonism of the α7nAChR disrupts PPI, rather with regard to the effects of KYNA, blockade of the glutamate recognition-site is necessary to reduce PPI.
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Affiliation(s)
- Klas Linderholm
- Dept. of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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Elevated levels of kynurenic acid change the dopaminergic response to amphetamine: implications for schizophrenia. Int J Neuropsychopharmacol 2009; 12:501-12. [PMID: 18796185 DOI: 10.1017/s1461145708009383] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Kynurenic acid (KYNA) is an endogenous compound implicated in the pathophysiology of schizophrenia. This tryptophan metabolite antagonizes both the N-methyl-D-aspartate (NMDA) receptors and the nicotinic alpha7* receptors at micromolar concentrations. In the present study the effects of amphetamine on dopamine (DA) release in the nucleus accumbens and on firing of DA neurons in the ventral tegmental area (VTA) were investigated in rats treated with kynurenine, the precursor of KYNA, in order to elevate brain KYNA levels. In rats subchronically treated with kynurenine (90 mg/kg x d for 6 d via osmotic minipumps, resulting in a 2-fold increase in whole-brain KYNA), the amphetamine-induced (2 mg/kg i.p.) increase in accumbal DA release was clearly enhanced compared to controls. Furthermore, subchronic treatment with kynurenine reduced the inhibitory action of amphetamine (0.2-25.6 mg/kg i.v.) on firing rate and burst firing activity of VTA DA neurons. A single dose of kynurenine (5 mg/kg s.c., 60 min, resulting in a 3-fold increase in whole-brain KYNA) did not alter the amphetamine-induced effects on DA neurotransmission compared to control rats. Present data are in agreement with the increased striatal DA release by amphetamine as observed by brain-imaging studies in patients with schizophrenia. Thus, subchronic elevation of rat brain KYNA, may rationally serve as an animal model similar to a pathophysiological condition of schizophrenia. It is proposed that the reduced responsivity of VTA DA neurons to the inhibitory action of amphetamine observed in rats with subchronically elevated KYNA levels may partly account for the increase in terminal DA release.
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Erhardt S, Olsson SK, Engberg G. Pharmacological manipulation of kynurenic acid: potential in the treatment of psychiatric disorders. CNS Drugs 2009; 23:91-101. [PMID: 19173370 DOI: 10.2165/00023210-200923020-00001] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The kynurenine pathway constitutes the main route of tryptophan degradation and generates the production of several neuroactive compounds; quinolinic acid is an excitotoxic NMDA receptor agonist, 3-hydroxykynurenine is a free-radical generator and kynurenic acid (KYNA) is an antagonist at glutamate and nicotinic receptors. In low micromolar concentrations, KYNA blocks the glycine site of the NMDA receptor and the nicotinic alpha(7) acetylcholine receptor. Knowledge regarding kynurenine metabolites and their involvement in neurophysiological processes has increased dramatically in recent years. In particular, endogenous KYNA appears to tightly control firing of midbrain dopamine neurons and to be involved in cognitive functions. Thus, decreased endogenous levels of rat brain KYNA have been found to reduce firing of these neurons, and mice with a targeted deletion of kynurenine aminotransferase II display low endogenous brain KYNA levels concomitant with an increased performance in cognitive tests. It is also suggested that kynurenines participate in the pathophysiology of psychiatric disorders. Thus, elevated levels of KYNA have been found in the CSF as well as in the post-mortem brain of patients with schizophrenia. Advantages in understanding how kynurenines can be pharmacologically manipulated may provide new possibilities in the treatment of psychiatric disorders, such as schizophrenia.
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Affiliation(s)
- Sophie Erhardt
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
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Schwieler L, Linderholm KR, Nilsson-Todd LK, Erhardt S, Engberg G. Clozapine interacts with the glycine site of the NMDA receptor: Electrophysiological studies of dopamine neurons in the rat ventral tegmental area. Life Sci 2008; 83:170-5. [DOI: 10.1016/j.lfs.2008.05.014] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2008] [Revised: 03/12/2008] [Accepted: 05/25/2008] [Indexed: 10/22/2022]
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Cowley TR, Fahey B, O’Mara SM. COX-2, but not COX-1, activity is necessary for the induction of perforant path long-term potentiation and spatial learningin vivo. Eur J Neurosci 2008; 27:2999-3008. [DOI: 10.1111/j.1460-9568.2008.06251.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Kynurenic acid attenuates MPP+-induced dopaminergic neuronal cell death via a Bax-mediated mitochondrial pathway. Eur J Cell Biol 2008; 87:389-97. [DOI: 10.1016/j.ejcb.2008.03.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Revised: 03/06/2008] [Accepted: 03/10/2008] [Indexed: 11/19/2022] Open
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Linderholm KR, Andersson A, Olsson S, Olsson E, Snodgrass R, Engberg G, Erhardt S. Activation of rat ventral tegmental area dopamine neurons by endogenous kynurenic acid: a pharmacological analysis. Neuropharmacology 2007; 53:918-24. [PMID: 17959203 DOI: 10.1016/j.neuropharm.2007.09.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Revised: 08/24/2007] [Accepted: 09/03/2007] [Indexed: 10/22/2022]
Abstract
Kynurenic acid (KYNA) is an endogenous NMDA receptor antagonist as well as a blocker of the alpha7* nicotinic receptor and mounting evidence suggests that the compound participates in the pathophysiology of schizophrenia. Previous studies have shown that elevated levels of endogenous KYNA are associated with an increased firing of midbrain dopamine (DA) neurons. In the present study, utilizing extracellular single unit cell recording techniques, the mechanism involved in this excitatory action of the compound was analyzed in male Sprague-Dawley rats. Administration of 4-chlorokynurenine (4-Cl-KYN; 25mg/kg, i.p.), which is converted to the selective NMDA glycine-site antagonist 7-chloro-kynurenic acid (7-Cl-KYNA), was found to increase firing rate and per cent burst firing activity of ventral tegmental area (VTA) DA neurons to the same magnitude as pretreatment of kynurenine (causing a 25-fold elevation in extracellular brain KYNA). Intravenous administration of the selective antagonist at the alpha7* nicotinic receptor methyllycaconitine (MLA; 1-4mg/kg) did not affect firing of VTA DA neurons, whereas intraperitoneal administration of this drug in a high dose (6mg/kg) was associated with a decreased firing rate and per cent burst firing activity. Administration of SDZ 220-581 (10mg/kg, i.v.), a competitive antagonist at the glutamate recognition-site of the NMDA receptor, was found to increase firing rate and per cent burst firing. Present results have potential implications for the treatment of schizophrenia, and indicate that the increased activity of VTA DA neurons following elevation of brain KYNA is mediated through glutamatergic rather than by nicotinergic mechanisms.
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Affiliation(s)
- Klas R Linderholm
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden
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39
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Erhardt S, Schwieler L, Nilsson L, Linderholm K, Engberg G. The kynurenic acid hypothesis of schizophrenia. Physiol Behav 2007; 92:203-9. [PMID: 17573079 DOI: 10.1016/j.physbeh.2007.05.025] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In recent years progress in the field of schizophrenia research has led to the suggestion that dopamine only plays an intermediary role in the pathophysiology of the disease and that the main abnormalities lie elsewhere. In particular, deficits in brain glutamatergic systems are suggested to play a prominent role in the pathophysiology of the disease. Kynurenic acid is an endogenous glutamate antagonist with a preferential action at the glycine-site of the N-methyl-D-aspartate-receptor. Mounting evidence indicates that the compound is significantly involved in basal neurophysiological processes in the brain. Thus, pharmacologically elevated levels of kynurenic acid, in similarity to systemic administration of phencyclidine or ketamine, were associated with increased firing rate and burst firing activity of midbrain dopamine neurons, indicating per se that elevated levels of brain kynurenic acid is associated with psychotomimetic effects. Indeed, cerebrospinal fluid level of kynurenic acid was elevated in schizophrenic patients as compared to healthy controls. The present paper also describes a prostaglandin-mediated regulation of kynurenic acid formation as well as a relationship between brain kynurenic acid concentration and the excitatory responses of ventral tegmental area dopamine neurons by clozapine and nicotine. Our results suggest that kynurenic acid contributes to the pathogenesis of schizophrenia and link the dopamine hypothesis of schizophrenia together with the idea of a deficiency in glutamatergic function in this disease.
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Affiliation(s)
- Sophie Erhardt
- Karolinska Institutet, Department of Physiology and Pharmacology, Stockholm, Sweden.
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Nilsson-Todd LK, Nordin C, Jönsson EG, Skogh E, Erhardt S. Cerebrospinal fluid kynurenic acid in male patients with schizophrenia - correlation with monoamine metabolites. Acta Neuropsychiatr 2007; 19:45-52. [PMID: 26952797 DOI: 10.1111/j.1601-5215.2006.00170.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND The tryptophan metabolite kynurenic acid (KYNA) is an endogenous glutamate/nicotinic receptor antagonist. Previous studies have shown that the concentration of the compound is increased in cerebrospinal fluid (CSF) of patients with schizophrenia. Furthermore, it has been found that the CSF concentration of KYNA is positively correlated to CSF concentrations of the monoamine metabolites homovanillic acid (HVA) and 5-hydroxy indoleacetic acid (5-HIAA) in healthy control subjects. OBJECTIVES To study the correlations between KYNA and the monoamine metabolites HVA, 5-HIAA and 4-hydroxy-3-methoxyphenylglycol (HMPG) in CSF of male patients (n= 53, ranging from 20 to 48 years of age) with verified schizophrenia. METHODS CSF was obtained by lumbar puncture, and KYNA analysis was performed with an isocratic reversed-phase high-performance liquid chromatography system connected to a fluorescence detector. HVA, 5-HIAA and HMPG concentrations were measured by mass fragmentography with deuterium-labelled internal standards. RESULTS Positive intercorrelations were found between CSF KYNA, HVA and 5-HIAA, while CSF content of HMPG did not correlate to KYNA or any of the monoamine metabolites in CSF. CONCLUSION The results of this study suggest that increased KYNA formation is associated with an increased dopamine and serotonin turnover in male patients with schizophrenia.
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Affiliation(s)
- Linda K Nilsson-Todd
- 1Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Conny Nordin
- 2Department of Neuroscience and Locomotion, Psychiatry Section, Linköpings Universitet, Linköping, Sweden
| | - Erik G Jönsson
- 3Department of Clinical Neuroscience, Psychiatry Section, HUBIN Project, Karolinska Institutet and Hospital, Stockholm, Sweden
| | - Elisabeth Skogh
- 2Department of Neuroscience and Locomotion, Psychiatry Section, Linköpings Universitet, Linköping, Sweden
| | - Sophie Erhardt
- 1Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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Abstract
In the last decade, the potential role of cyclooxygenase-2 (COX-2) and prostaglandins (PGs) in brain diseases has been extensively studied. COX-2 over-expression has been associated with neurotoxiticy in acute conditions, such as hypoxia/ischemia and seizures, as well as in inflammatory chronic diseases, including Creutzfeldt-Jakob disease (CJD) and Alzheimer's disease (AD). However, the role played by COX-2 in neurodegenerative diseases is still controversial and further clinical and experimental studies are warranted. In addition, the emerging role of COX-2 in behavioural and cognitive functions strongly indicates that studies aimed at improving our knowledge of the physiological role of COX-2 in the central nervous system are crucial to fully understand the pros and cons of its manipulation in disabling neurological diseases.
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Affiliation(s)
- Luisa Minghetti
- Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Rome, Italy
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Atlas A, Gisslén M, Nordin C, Lindström L, Schwieler L. Acute psychotic symptoms in HIV-1 infected patients are associated with increased levels of kynurenic acid in cerebrospinal fluid. Brain Behav Immun 2007; 21:86-91. [PMID: 16603336 DOI: 10.1016/j.bbi.2006.02.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2005] [Revised: 01/27/2006] [Accepted: 02/26/2006] [Indexed: 11/21/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) infection is associated with psychiatric complications including cognitive impairment, affective disorders, and psychosis. Previous studies have revealed a disturbed kynurenine metabolism in these patients leading to increased levels of neuroactive compounds acting at glutamatergic neurotransmission. Kynurenic acid (KYNA), one of these metabolites is a glutamate-receptor antagonist, preferentially blocking the glycine site of the N-methyl-d-aspartate (NMDA) receptor. Increased levels of brain KYNA have been suggested to induce a NMDA receptor hypofunction that is associated with psychotic symptoms. In the present study, we analyze the concentration of KYNA in the cerebrospinal fluid (CSF) from HIV-1 infected patients (n=22), including HIV-1 infected patients with psychotic symptoms (n=8) and HIV-1 infected patients without psychiatric symptoms (n=14). We found that HIV-1 infected patients had significantly higher median concentration of CSF KYNA (3.02nM) compared to healthy controls (1.17nM). Furthermore, CSF KYNA levels were significantly elevated in HIV-1 infected patients with psychotic symptoms (4.54nM) compared to patients with HIV-1 without psychiatric symptoms (2.28nM). Present results indicate that increased levels of CSF KYNA may be associated with development of psychotic symptoms in HIV-1 infected patients.
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Affiliation(s)
- Ann Atlas
- Infectious Diseases Unit, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, SE-171 76 Stockholm, Sweden.
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Margolis EB, Lock H, Hjelmstad GO, Fields HL. The ventral tegmental area revisited: is there an electrophysiological marker for dopaminergic neurons? J Physiol 2006; 577:907-24. [PMID: 16959856 PMCID: PMC1890372 DOI: 10.1113/jphysiol.2006.117069] [Citation(s) in RCA: 395] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The ventral tegmental area (VTA) and in particular VTA dopamine (DA) neurons are postulated to play a central role in reward, motivation and drug addiction. However, most evidence implicating VTA DA neurons in these functions is based on indirect electrophysiological characterization, rather than cytochemical identification. These physiological criteria were first established in the substantia nigra pars compacta (SNc), but their validity in the VTA is uncertain. In the current study we found that while 88 +/- 2% of SNc neurons labelled by the neuronal marker NeuN were co-labelled for the catecholamine enzyme tyrosine hydroxylase (TH), a much smaller percentage (55 +/- 2%) of VTA neurons co-expressed TH. In addition, using in vitro whole-cell recordings we found that widely accepted physiological criteria for VTA DA neurons, including the hyperpolarization-activated inwardly rectifying non-specific cation current (I(h)), spike duration, and inhibition by DA D2 receptor agonists, do not reliably predict the DA content of VTA neurons. We could not distinguish DA neurons from other VTA neurons by size, shape, input resistance, I(h) size, or spontaneous firing rate. Although the absence of an I(h) reliably predicted that a VTA neuron was non-dopaminergic, and I(h)(-) neurons differ from I(h)(+) neurons in firing rate, interspike interval (ISI) standard deviation, and ISI skew, no physiological property examined here is both sensitive and selective for DA neurons in the VTA. We conclude that reliable physiological criteria for VTA DA neuron identification have yet to be determined, and that the criteria currently being used are unreliable.
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Affiliation(s)
- Elyssa B Margolis
- Ernest Gallo Clinic & Research Center, University of California-San Francisco, Emeryville, CA 94608, USA.
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