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Gamma camera imaging in psychiatric disorders. Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00222-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Kalyoncu A, Gonul AS. The Emerging Role of SPECT Functional Neuroimaging in Schizophrenia and Depression. Front Psychiatry 2021; 12:716600. [PMID: 34975556 PMCID: PMC8714796 DOI: 10.3389/fpsyt.2021.716600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 11/15/2021] [Indexed: 11/13/2022] Open
Abstract
Over the last three decades, the brain's functional and structural imaging has become more prevalent in psychiatric research and clinical application. A substantial amount of psychiatric research is based on neuroimaging studies that aim to illuminate neural mechanisms underlying psychiatric disorders. Single-photon emission computed tomography (SPECT) is one of those developing brain imaging techniques among various neuroimaging technologies. Compared to PET, SPECT imaging is easy, less expensive, and practical for radioligand use. Current technologies increased the spatial accuracy of SPECT findings by combining the functional SPECT images with CT images. The radioligands bind to receptors such as 5-hydroxytryptamine 2A, and dopamine transporters can help us comprehend neural mechanisms of psychiatric disorders based on neurochemicals. This mini-review focuses on the SPECT-based neuroimaging approach to psychiatric disorders such as schizophrenia and major depressive disorder (MDD). Research-based SPECT findings of psychiatric disorders indicate that there are notable changes in biochemical components in certain disorders. Even though many studies support that SPECT can be used in psychiatric clinical practice, we still only use subjective diagnostic criteria such as the Diagnostic Statistical Manual of Mental Disorders (DSM-5). Glimpsing into the brain's biochemical world via SPECT in psychiatric disorders provides more information about the pathophysiology and future implication of neuroimaging techniques.
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Affiliation(s)
- Anil Kalyoncu
- Department of Psychiatry, Ege University School of Medicine, Izmir, Turkey
| | - Ali Saffet Gonul
- Department of Psychiatry, Ege University School of Medicine, Izmir, Turkey
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Ermert J, Benešová M, Hugenberg V, Gupta V, Spahn I, Pietzsch HJ, Liolios C, Kopka K. Radiopharmaceutical Sciences. Clin Nucl Med 2020. [DOI: 10.1007/978-3-030-39457-8_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Neuroimaging studies of GABA in schizophrenia: a systematic review with meta-analysis. Transl Psychiatry 2017; 7:e1147. [PMID: 28585933 PMCID: PMC5537645 DOI: 10.1038/tp.2017.124] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 04/26/2017] [Accepted: 05/03/2017] [Indexed: 01/17/2023] Open
Abstract
Data from animal models and from postmortem studies suggest that schizophrenia is associated with brain GABAergic dysfunction. The extent to which this is reflected in data from in vivo studies of GABA function in schizophrenia is unclear. The Medline database was searched to identify articles published until 21 October 2016. The search terms included GABA, proton magnetic resonance spectroscopy (1H-MRS), positron emission tomography (PET), single photon emission computed tomography (SPECT), schizophrenia and psychosis. Sixteen GABA 1H-MRS studies (538 controls, 526 patients) and seven PET/SPECT studies of GABAA/benzodiazepine receptor (GABAA/BZR) availability (118 controls, 113 patients) were identified. Meta-analyses of 1H-MRS GABA in the medial prefrontal cortex (mPFC), parietal/occipital cortex (POC) and striatum did not show significant group differences (mFC: g=-0.3, 409 patients, 495 controls, 95% confidence interval (CI): -0.6 to 0.1; POC: g=-0.3, 139 patients, 111 controls, 95% CI: -0.9 to 0.3; striatum: g=-0.004, 123 patients, 95 controls, 95% CI: -0.7 to 0.7). Heterogeneity across studies was high (I2>50%), and this was not explained by subsequent moderator or meta-regression analyses. There were insufficient PET/SPECT receptor availability studies for meta-analyses, but a systematic review did not suggest replicable group differences in regional GABAA/BZR availability. The current literature does not reveal consistent alterations in in vivo GABA neuroimaging measures in schizophrenia, as might be hypothesized from animal models and postmortem data. The analysis highlights the need for further GABA neuroimaging studies with improved methodology and addressing potential sources of heterogeneity.
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Ahn KH, Sewell A, Elander J, Pittman B, Ranganathan M, Gunduz-Bruce H, Krystal J, D'Souza DC. Role of GABA Deficit in Sensitivity to the Psychotomimetic Effects of Amphetamine. Neuropsychopharmacology 2015; 40:2822-31. [PMID: 25953357 PMCID: PMC4864658 DOI: 10.1038/npp.2015.132] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 03/26/2015] [Accepted: 04/20/2015] [Indexed: 11/10/2022]
Abstract
Some schizophrenia patients are more sensitive to amphetamine (AMPH)-induced exacerbations in psychosis-an effect that correlates with higher striatal dopamine release. This enhanced vulnerability may be related to gamma-aminobutyric acid (GABA) deficits observed in schizophrenia. We hypothesized that a pharmacologically induced GABA deficit would create vulnerability to the psychotomimetic effects to the 'subthreshold' dose of AMPH in healthy subjects, which by itself would not induce clinically significant increase in positive symptoms. To test this hypothesis, a GABA deficit was induced by intravenous infusion of iomazenil (IOM; 3.7 μg/kg), an antagonist and partial inverse agonist of benzodiazepine receptor. A subthreshold dose of AMPH (0.1 mg/kg) was administered by intravenous infusion. Healthy subjects received placebo IOM followed by placebo AMPH, active IOM followed by placebo AMPH, placebo IOM followed by active AMPH, and active IOM followed by active AMPH in a randomized, double-blind crossover design over 4 test days. Twelve healthy subjects who had a subclinical response to active AMPH alone were included in the analysis. Psychotomimetic effects (Positive and Negative Syndrome Scale (PANSS)), perceptual alterations (Clinician Administered Dissociative Symptoms Scale (CADSS)), and subjective effects (visual analog scale) were captured before and after the administration of drugs. IOM significantly augmented AMPH-induced peak changes in PANSS positive symptom subscale and both subjective and objective CADSS scores. There were no pharmacokinetic interactions. In conclusion, GABA deficits increased vulnerability to amphetamine-induced psychosis-relevant effects in healthy subjects, suggesting that pre-existing GABA deficits may explain why a subgroup of schizophrenia patients are vulnerable to AMPH.
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Affiliation(s)
- Kyung-Heup Ahn
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, West Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, West Haven, CT, USA
| | - Andrew Sewell
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, West Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, West Haven, CT, USA
| | - Jacqueline Elander
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, West Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, West Haven, CT, USA
| | - Brian Pittman
- Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, West Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, West Haven, CT, USA
| | - Mohini Ranganathan
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, West Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, West Haven, CT, USA
| | - Handan Gunduz-Bruce
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, West Haven, CT, USA
| | - John Krystal
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, West Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, West Haven, CT, USA
| | - Deepak Cyril D'Souza
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, West Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, West Haven, CT, USA,Psychiatry Service, VA Connecticut Healthcare System, 950 Campbell Avenue, West Haven, CT 06516, USA, Tel: +1 860 203 932 5711, Fax: +1 860 203 937 4860, E-mail:
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Frankle WG, Cho RY, Prasad KM, Mason NS, Paris J, Himes ML, Walker C, Lewis DA, Narendran R. In vivo measurement of GABA transmission in healthy subjects and schizophrenia patients. Am J Psychiatry 2015; 172:1148-59. [PMID: 26133962 PMCID: PMC5070491 DOI: 10.1176/appi.ajp.2015.14081031] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Postmortem studies in schizophrenia reveal alterations in gene products that regulate the release and extracellular persistence of GABA. However, results of in vivo studies of schizophrenia measuring total tissue GABA with magnetic resonance spectroscopy (MRS) have been inconsistent. Neither the postmortem nor the MRS studies directly address the physiological properties of GABA neurotransmission. The present study addresses this question through an innovative positron emission tomography (PET) paradigm. METHOD The binding of [(11)C]flumazenil, a benzodiazepine-specific PET radiotracer, was measured before and after administration of tiagabine (0.2 mg/kg of body weight), a GABA membrane transporter (GAT1) blocker, in 17 off-medication patients with schizophrenia and 22 healthy comparison subjects. Increased extracellular GABA, through GAT1 blockade, enhances the affinity of GABAA receptors for benzodiazepine ligands, detected as an increase in [(11)C]flumazenil tissue distribution volume (VT). RESULTS [(11)C]Flumazenil VT was significantly increased across all cortical brain regions in the healthy comparison group but not in the schizophrenia group. This lack of effect was most prominent in the antipsychotic-naive schizophrenia group. In this subgroup, [(11)C]flumazenil ΔVT in the medial temporal lobe was correlated with positive symptoms, and baseline [(11)C]flumazenil VT in the medial temporal lobe was negatively correlated with visual learning. In the healthy comparison group but not the schizophrenia group, [(11)C]flumazenil ΔVT was positively associated with gamma-band oscillation power. CONCLUSIONS This study demonstrates, for the first time, an in vivo impairment in GABA transmission in schizophrenia, most prominent in antipsychotic-naive individuals. The impairment in GABA transmission appears to be linked to clinical symptoms, disturbances in cortical oscillations, and cognition.
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GABA abnormalities in schizophrenia: a methodological review of in vivo studies. Schizophr Res 2015; 167:84-90. [PMID: 25458856 PMCID: PMC4409914 DOI: 10.1016/j.schres.2014.10.011] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Revised: 10/04/2014] [Accepted: 10/07/2014] [Indexed: 12/31/2022]
Abstract
Abnormalities of GABAergic interneurons are some of the most consistent findings from post-mortem studies of schizophrenia. However, linking these molecular deficits with in vivo observations in patients - a critical goal in order to evaluate interventions that would target GABAergic deficits - presents a challenge. Explanatory models have been developed based on animal work and the emerging experimental literature in schizophrenia patients. This literature includes: neuroimaging ligands to GABA receptors, magnetic resonance spectroscopy (MRS) of GABA concentration, transcranial magnetic stimulation of cortical inhibitory circuits and pharmacologic probes of GABA receptors to dynamically challenge the GABA system, usually in combination with neuroimaging studies. Pharmacologic challenges have elicited behavioral changes, and preliminary studies of therapeutic GABAergic interventions have been conducted. This article critically reviews the evidence for GABAergic dysfunction from each of these areas. These methods remain indirect measures of GABAergic function, and a broad array of dysfunction is linked with the putative GABAergic measures, including positive symptoms, cognition, emotion, motor processing and sensory processing, covering diverse brain areas. Measures of receptor binding have not shown replicable group differences in binding, and MRS assays of GABA concentration have yielded equivocal evidence of large-scale alteration in GABA concentration. Overall, the experimental base remains sparse, and much remains to be learned about the role of GABAergic interneurons in healthy brains. Challenges with pharmacologic and functional probes show promise, and may yet enable a better characterization of GABAergic deficits in schizophrenia.
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GABA Deficits Enhance the Psychotomimetic Effects of Δ9-THC. Neuropsychopharmacology 2015; 40:2047-56. [PMID: 25728472 PMCID: PMC4839528 DOI: 10.1038/npp.2015.58] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 02/09/2015] [Accepted: 02/18/2015] [Indexed: 11/08/2022]
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Nagamitsu S, Yamashita Y, Tanigawa H, Chiba H, Kaida H, Ishibashi M, Kakuma T, Croarkin PE, Matsuishi T. Upregulated GABA Inhibitory Function in ADHD Children with Child Behavior Checklist-Dysregulation Profile: 123I-Iomazenil SPECT Study. Front Psychiatry 2015; 6:84. [PMID: 26082729 PMCID: PMC4451796 DOI: 10.3389/fpsyt.2015.00084] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 05/18/2015] [Indexed: 11/23/2022] Open
Abstract
The child behavior checklist-dysregulation profile (CBCL-DP) refers to a pattern of elevated scores on the attention problems, aggression, and anxiety/depression subscales of the child behavior checklist. The aim of the present study was to investigate the potential role of GABA inhibitory neurons in children with attention deficit/hyperactivity disorder (ADHD) and dysregulation assessed with a dimensional measure. Brain single photon emission computed tomography (SPECT) was performed in 35 children with ADHD using 123I-iomazenil, which binds with high affinity to benzodiazepine receptors. Iomazenil binding activities were assessed with respect to the presence or absence of a threshold CBCL-DP (a score ≥210 for the sum of the three subscales: Attention Problems, Aggression, and Anxiety/Depression). We then attempted to identify which CBCL-DP subscale explained the most variance with respect to SPECT data, using "age," "sex," and "history of maltreatment" as covariates. Significantly higher iomazenil binding activity was seen in the posterior cingulate cortex (PCC) of ADHD children with a significant CBCL-DP. The Anxiety/Depression subscale on the CBCL had significant effects on higher iomazenil binding activity in the left superior frontal, middle frontal, and temporal regions, as well as in the PCC. The present brain SPECT findings suggest that GABAergic inhibitory neurons may play an important role in the neurobiology of the CBCL-DP, in children with ADHD.
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Affiliation(s)
- Shinichiro Nagamitsu
- Department of Pediatrics and Child Health, Kurume University School of Medicine , Fukuoka , Japan
| | - Yushiro Yamashita
- Department of Pediatrics and Child Health, Kurume University School of Medicine , Fukuoka , Japan
| | - Hitoshi Tanigawa
- Department of Radiology, Kurume University School of Medicine , Fukuoka , Japan
| | - Hiromi Chiba
- Department of Psychiatry, Kurume University School of Medicine , Fukuoka , Japan
| | - Hayato Kaida
- Department of Radiology, Kurume University School of Medicine , Fukuoka , Japan
| | - Masatoshi Ishibashi
- Department of Radiology, Kurume University School of Medicine , Fukuoka , Japan
| | - Tatsuyuki Kakuma
- Biostatistics Center, Kurume University School of Medicine , Fukuoka , Japan
| | - Paul E Croarkin
- Department of Psychiatry and Psychology, Mayo Clinic, Rochester , MN , USA
| | - Toyojiro Matsuishi
- Department of Pediatrics and Child Health, Kurume University School of Medicine , Fukuoka , Japan
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Chana G, Bousman CA, Money TT, Gibbons A, Gillett P, Dean B, Everall IP. Biomarker investigations related to pathophysiological pathways in schizophrenia and psychosis. Front Cell Neurosci 2013; 7:95. [PMID: 23805071 PMCID: PMC3693064 DOI: 10.3389/fncel.2013.00095] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 06/03/2013] [Indexed: 12/28/2022] Open
Abstract
Post-mortem brain investigations of schizophrenia have generated swathes of data in the last few decades implicating candidate genes and protein. However, the relation of these findings to peripheral biomarker indicators and symptomatology remain to be elucidated. While biomarkers for disease do not have to be involved with underlying pathophysiology and may be largely indicative of diagnosis or prognosis, the ideal may be a biomarker that is involved in underlying disease processes and which is therefore more likely to change with progression of the illness as well as potentially being more responsive to treatment. One of the main difficulties in conducting biomarker investigations for major psychiatric disorders is the relative inconsistency in clinical diagnoses between disorders such as bipolar and schizophrenia. This has led some researchers to investigate biomarkers associated with core symptoms of these disorders, such as psychosis. The aim of this review is to evaluate the contribution of post-mortem brain investigations to elucidating the pathophysiology pathways involved in schizophrenia and psychosis, with an emphasis on major neurotransmitter systems that have been implicated. This data will then be compared to functional neuroimaging findings as well as findings from blood based gene expression investigations in schizophrenia in order to highlight the relative overlap in pathological processes between these different modalities used to elucidate pathogenesis of schizophrenia. In addition we will cover some recent and exciting findings demonstrating microRNA (miRNA) dysregulation in both the blood and the brain in patients with schizophrenia. These changes are pertinent to the topic due to their known role in post-transcriptional modification of gene expression with the potential to contribute or underlie gene expression changes observed in schizophrenia. Finally, we will discuss how post-mortem studies may aid future biomarker investigations.
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Affiliation(s)
- Gursharan Chana
- Department of Psychiatry, Melbourne Brain Centre, The University of Melbourne Parkville, VIC, Australia
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Abstract
The history of the chemical synthesis and animal/human pharmacology of phencyclidine is documented. From its early use as a general anesthetic, chemical model of schizophrenia, and drug of abuse, phencyclidine has had a checkered history. Research with this agent and its chemical derivatives like ketamine have provided a solid foundation for just a beginning to understanding the neuropathology of schizophrenia.
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Affiliation(s)
- Edward F. Domino
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109-5632,To whom correspondence should be addressed; tel: 734-764-9115, fax: 734-763-4450, e-mail:
| | - Elliot D. Luby
- Department of Psychiatry and Behavioral Sciences, Wayne State University, Detroit, MI,Comprehensive Psychiatric Services, Farmington Hills, MI
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Abstract
The results of imaging studies have played an important role in the formulation of hypotheses regarding the etiology of psychosis and schizophrenia, as well as in our understanding of the mechanisms of action of antipsychotics. Since this volume is primarily directed to molecular aspects of psychosis and antipsychotics, only the results of molecular imaging techniques addressing these topics will be discussed here.One of the most consistent findings of molecular imaging studies in schizophrenia is an increased uptake of DOPA in the striatum, which may be interpreted as an increased synthesis of L-DOPA. Also, several studies reported an increased release of dopamine induced by amphetamine in schizophrenia patients. These findings played an important role in reformulating the dopamine hypothesis of schizophrenia. To study the roles of the neurotransmitters γ-aminobutyric acid (GABA) and glutamate in schizophrenia, SPECT as well as MR spectroscopy have been used. The results of preliminary SPECT studies are consistent with the hypothesis of NMDA receptor dysfunction in schizophrenia. Regarding the GABA deficit hypothesis of schizophrenia, imaging results are inconsistent. No changes in serotonin transporters were demonstrated in imaging studies in schizophrenia, but studies of several serotonin receptors showed conflicting results. The lack of selective radiotracers for muscarinic receptors may have hampered examination of this system in schizophrenia as well as its role in the induction of side effects of antipsychotics. Interestingly, preliminary molecular imaging studies on the cannabinoid-1 receptor and on neuroinflammatory processes in schizophrenia have recently been published. Finally, a substantial number of PET/SPECT studies have examined the occupancy of receptors by antipsychotics and an increasing number of studies is now focusing on the effects of these drugs using techniques like spectroscopy and pharmacological MRI.
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Vinkers CH, Mirza NR, Olivier B, Kahn RS. The inhibitory GABA system as a therapeutic target for cognitive symptoms in schizophrenia: investigational agents in the pipeline. Expert Opin Investig Drugs 2011; 19:1217-33. [PMID: 20812877 DOI: 10.1517/13543784.2010.513382] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
IMPORTANCE OF THE FIELD Cognitive impairments associated with schizophrenia include neuropsychological deficits in attention, working memory, learning and executive function. Because these cognitive deficits precede the onset of psychosis, are present in non-affected relatives and constitute the best predictor of functional outcome, they are a cardinal clinical feature in schizophrenia. Currently, no effective treatment for the cognitive symptoms in schizophrenia exists. AREAS COVERED IN THIS REVIEW There is evidence that the inhibitory GABA system is affected in schizophrenia, suggesting that cognitive impairments associated with schizophrenia may be effectively treated by drugs that modulate the GABA(A) receptor. However, classical benzodiazepines produce cognitive impairments and are associated with numerous side effects. The recent development of compounds with selective efficacy for different α subunits at the benzodiazepine site of the GABA(A) receptor has renewed interest for the therapeutic potential of GABAergic drugs. WHAT THE READER WILL GAIN This review summarizes the involvement of the inhibitory GABA system in the cognitive abnormalities of schizophrenia and discusses putative (selective) GABAergic cognition-enhancing drugs for schizophrenia. TAKE HOME MESSAGE If cognitive abnormalities in schizophrenic individuals are the result of GABAergic dysfunction, selectively modulating the GABA system could comprise a promising therapeutic intervention for cognitive symptoms in schizophrenia.
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Affiliation(s)
- Christiaan H Vinkers
- Department of Psychiatry, University Medical Center Utrecht, Rudolf Magnus Institute of Neuroscience, Utrecht, The Netherlands
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Ahn K, Gil R, Seibyl J, Sewell RA, D'Souza DC. Probing GABA receptor function in schizophrenia with iomazenil. Neuropsychopharmacology 2011; 36:677-83. [PMID: 21068719 PMCID: PMC3055690 DOI: 10.1038/npp.2010.198] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Several lines of evidence from post-mortem, brain imaging, and genetic studies in schizophrenia patients suggest that Gamma-amino butyric acid (GABA) deficits may contribute to the pathophysiology of schizophrenia. Pharmacological induction of a transient GABA-deficit state has been shown to enhance vulnerability of healthy subjects to the psychotomimetic effects of various drugs. Exacerbating or creating a GABA deficit was hypothesized to induce or unmask psychosis in schizophrenia patients, but not in healthy controls. To test this hypothesis, a transient GABA deficit was pharmacologically induced in schizophrenia patients and healthy controls using iomazenil, an antagonist and partial inverse agonist of the benzodiazepine receptor. In a double-blind, randomized, placebo-controlled study, clinically stable chronic schizophrenia patients (n=13) received iomazenil (3.7 μg administered intravenously over 10 min). Psychosis was measured using the Brief Psychiatric Rating Scale and perceptual alterations were measured using the Clinician Administered Dissociative Symptoms Scale before and after iomazenil administration. These data were compared with the effects of iomazenil in healthy subjects (n=20). Iomazenil produced increases in psychotic symptoms and perceptual alterations in schizophrenia patients, but not in healthy controls. The greater vulnerability of schizophrenia patients to the effects of iomazenil relative to controls provides further support for the GABA-deficit hypothesis of schizophrenia.
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Affiliation(s)
- Kyungheup Ahn
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Roberto Gil
- Department of Psychiatry, Columbia University School of Medicine, New York, NY, USA
| | - John Seibyl
- Institute for Neurodegenerative Disorders, New Haven, CT, USA
| | - Richard Andrew Sewell
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Deepak Cyril D'Souza
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,Psychiatry Service, 116A, VA Connecticut Healthcare System, 950 Campbell Avenue, West Haven, CT 06516, USA, Tel: +1 03 932 5711x 2594, Fax: +1 03 937 4860, E-mail:
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McLeod MC, Scarr E, Dean B. Effects of benzodiazepine treatment on cortical GABA(A) and muscarinic receptors: studies in schizophrenia and rats. Psychiatry Res 2010; 179:139-46. [PMID: 20483174 DOI: 10.1016/j.psychres.2009.03.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Revised: 03/24/2009] [Accepted: 03/25/2009] [Indexed: 11/30/2022]
Abstract
Changes in cortical γ-aminobutyric acid A (GABA(A)) receptors and muscarinic receptors have been reported in schizophrenia, a disorder treated with antipsychotic drugs and benzodiazepines. As there is a reported functional relationship between the GABAergic and cholinergic systems in the human central nervous system we have investigated whether there are changes in the GABA(A) and muscarinic receptors in the cortex of subjects from APD-treated subjects with schizophrenia and whether changes were different in subjects who had also received benzodiazepine treatment. We failed to show any strong correlations between changes in GABA(A) and muscarinic receptors in the CNS of subjects with schizophrenia. We showed that subjects with schizophrenia treated with benzodiazepines had lower levels of muscarinic receptors; which was not the case in rats treated with APDs, benzodiazepines or a combination of both drugs. Further, the benzodiazepine binding site, but not the muscimol binding site, was decreased in the parietal cortex of subjects with schizophrenia independent of benzodiazepine status at death. These data would therefore support our previously stated hypotheses that changes in the cortical cholinergic and GABAergic systems are involved in the pathophysiology of schizophrenia.
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Affiliation(s)
- Mark C McLeod
- The Rebecca L. Cooper Research Laboratories, The Mental Health Research Institute, Parkville, Australia
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Tayoshi S, Nakataki M, Sumitani S, Taniguchi K, Shibuya-Tayoshi S, Numata S, Iga JI, Ueno SI, Harada M, Ohmori T. GABA concentration in schizophrenia patients and the effects of antipsychotic medication: a proton magnetic resonance spectroscopy study. Schizophr Res 2010; 117:83-91. [PMID: 20022731 DOI: 10.1016/j.schres.2009.11.011] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 11/18/2009] [Accepted: 11/21/2009] [Indexed: 10/20/2022]
Abstract
Gamma-amino butyric acid (GABA) is thought to play a role in the pathophysiology of schizophrenia. High magnetic field proton magnetic resonance spectroscopy ((1)H-MRS) provides a reliable measurement of GABA in specific regions of the brain. This study measured GABA concentration in the anterior cingulate cortex (ACC) and in the left basal ganglia (ltBG) in 38 patients with chronic schizophrenia and 29 healthy control subjects. There was no significant difference in GABA concentration between the schizophrenia patients and the healthy controls in either the ACC (1.36+/-0.45 mmol/l in schizophrenia patients and 1.52+/-0.54 mmol/l in control subjects) or the ltBG (1.13+/-0.26 mmol/l in schizophrenia patients and 1.18+/-0.20 mmol/l in control subjects). Among the right handed schizophrenia patients, the GABA concentration in the ltBG was significantly higher in patients taking typical antipsychotics (1.25+/-0.24 mmol/l) than in those taking atypical antipsychotics (1.03+/-0.24 mmol/l, p=0.026). In the ACC, the GABA concentration was negatively correlated with the dose of the antipsychotics (rs=-0.347, p=0.035). In the ltBG, the GABA concentration was positively correlated with the dose of the anticholinergics (rs=0.403, p=0.015). To the best of our knowledge, this is the first study to have directly measured GABA concentrations in schizophrenia patients using (1)H-MRS. Our results suggest that there are no differences in GABA concentrations in the ACC or the ltBG of schizophrenia patients compared to healthy controls. Antipsychotic medication may cause changes in GABA concentration, and atypical and typical antipsychotics may have differing effects. It is possible that medication effects conceal inherent differences in GABA concentrations between schizophrenia patients and healthy controls.
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Affiliation(s)
- Shin'Ya Tayoshi
- Department of Psychiatry, Course of Integrated Brain Sciences, Medical Informatics, Institute of Health Biosciences, The University of Tokushima Graduate School, Japan
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Abstract
Recent advances in the development and applications of neurochemical brain imaging methods have improved the ability to study the neurochemistry of the living brain in normal processes as well as psychiatric disorders. In particular, positron emission tomography (PET) and single photon emission computed tomography (SPECT) have been used to determine neurochemical substrates of schizophrenia and to uncover the mechanism of action of antipsychotic medications. The growing availability of radiotracers for monoaminergic neurotransmitter synthesis, transporters and receptors, has enabled the evaluation of hypotheses regarding neurotransmitter function in schizophrenia derived from preclinical and clinical observations. This chapter reviews the studies using neurochemical brain imaging methods for (1) detection of abnormalities in indices of dopamine and serotonin transmission in patients with schizophrenia compared to controls, (2) development of new tools to study other neurotransmitters systems, such as gamma-aminobutyric acid (GABA) and glutamate, and (3) characterization of target occupancy by antipsychotic drugs, as well as its relationship to efficacy and side effects. As more imaging tools become available, this knowledge will expand and will lead to better detection of disease, as well as better therapeutic approaches.
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Affiliation(s)
- Nina Urban
- Department of Psychiatry, New York State Psychiatric Institute, Columbia University, New York, NY 10032, USA.
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Abstract
After decades of research aimed at elucidating the pathophysiology and etiology of schizophrenia, it has become increasingly apparent that it is an illness knowing few boundaries. Psychopathological manifestations extend across several domains, impacting multiple facets of real-world functioning for the affected individual. Even within one such domain, arguably the most enduring, difficult to treat, and devastating to long-term functioning-executive impairment-there are not only a host of disrupted component processes, but also a complex underlying dysfunctional neural architecture. Further, just as implicated brain structures (eg, dorsolateral prefrontal cortex) through postmortem and neuroimaging techniques continue to show alterations in multiple, interacting signaling pathways, so too does evolving understanding of genetic risk factors suggest multiple molecular entry points to illness liability. With this expansive network of interactions in mind, the present chapter takes a systems-level approach to executive dysfunction in schizophrenia, by identifying key regions both within and outside of the frontal lobes that show changes in schizophrenia and are important in cognitive control neural circuitry, summarizing current knowledge of their relevant functional interactions, and reviewing emerging links between schizophrenia risk genetics and characteristic executive circuit aberrancies observed with neuroimaging methods.
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Nikolaus S, Antke C, Müller HW. In vivo imaging of synaptic function in the central nervous system: II. Mental and affective disorders. Behav Brain Res 2009; 204:32-66. [DOI: 10.1016/j.bbr.2009.06.009] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 05/27/2009] [Accepted: 06/02/2009] [Indexed: 10/20/2022]
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Thompson JL, Urban N, Abi-Dargham A. How have developments in molecular imaging techniques furthered schizophrenia research? ACTA ACUST UNITED AC 2009; 1:135-153. [PMID: 21243081 DOI: 10.2217/iim.09.22] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Molecular imaging techniques have led to significant advances in understanding the pathophysiology of schizophrenia and contributed to knowledge regarding potential mechanisms of action of the drugs used to treat this illness. The aim of this article is to provide a review of the major findings related to the application of molecular imaging techniques that have furthered schizophrenia research. This article focuses specifically on neuroreceptor imaging studies with PET and SPECT. After providing a brief overview of neuroreceptor imaging methodology, we consider relevant findings from studies of receptor availability, and dopamine synthesis and release. Results are discussed in the context of current hypotheses regarding neurochemical alterations in the illness. We then selectively review pharmacological occupancy studies and the role of neuroreceptor imaging in drug development for schizophrenia.
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Affiliation(s)
- Judy L Thompson
- Department of Psychiatry, Columbia University and New York State Psychiatric Institute, 1051 Riverside Drive, Unit 31, New York, NY 10032, USA
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Heinzel A, Steinke R, Poeppel TD, Grosser O, Bogerts B, Otto H, Northoff G. S-ketamine and GABA-A-receptor interaction in humans: an exploratory study with I-123-iomazenil SPECT. Hum Psychopharmacol 2008; 23:549-54. [PMID: 18546441 DOI: 10.1002/hup.960] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE We aimed to probe for regional cerebral effects of S-ketamine on in vivo GABA-A-receptor binding in healthy human subjects. METHODS We investigated I-123-iomazenil SPECT before, during and after administration of S-ketamine in a blinded placebo-controlled study design (n = 12 in both groups). Analyses of SPECT were performed with voxel-based statistical parametric mapping (SPM), and statistical comparisons were made between the groups. We also assessed biochemical and behavioural changes during S-ketamine infusion. RESULTS S-ketamine induced positive and negative symptoms measured by the Brief Psychiatric Rating scale (BPRS). It increased the cortisol and prolactin levels. Image analysis revealed significantly decreased I-123-iomazenil binding in bilateral dorsomedial prefrontal cortex during S-ketamine administration when compared to placebo. CONCLUSION Our study delivers preliminary evidence for an in vivo interaction of S-ketamine with GABA-A-receptors in human dorsomedial prefrontal cortex.
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Affiliation(s)
- Alexander Heinzel
- Department of Psychiatry, University of Magdeburg, Magdeburg, Germany.
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Asai Y, Takano A, Ito H, Okubo Y, Matsuura M, Otsuka A, Takahashi H, Ando T, Ito S, Arakawa R, Asai K, Suhara T. GABAA/Benzodiazepine receptor binding in patients with schizophrenia using [11C]Ro15-4513, a radioligand with relatively high affinity for alpha5 subunit. Schizophr Res 2008; 99:333-40. [PMID: 18042347 DOI: 10.1016/j.schres.2007.10.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Revised: 09/16/2007] [Accepted: 10/18/2007] [Indexed: 12/30/2022]
Abstract
Dysfunction of the GABA system is considered to play a role in the pathology of schizophrenia. Individual subunits of GABA(A)/Benzodiazepine (BZ) receptor complex have been revealed to have different functional properties. alpha5 subunit was reported to be related to learning and memory. Changes of alpha5 subunit in schizophrenia were reported in postmortem studies, but the results were inconsistent. In this study, we examined GABA(A)/BZ receptor using [(11)C]Ro15-4513, which has relatively high affinity for alpha5 subunit, and its relation to clinical symptoms in patients with schizophrenia. [(11)C]Ro15-4513 bindings of 11 patients with schizophrenia (6 drug-naïve and 5 drug-free) were compared with those of 12 age-matched healthy control subjects using positron emission tomography. Symptoms were assessed using the Positive and Negative Syndrome Scale. [(11)C]Ro15-4513 binding was quantified by binding potential (BP) obtained by the reference tissue model. [(11)C]Ro15-4513 binding in the prefrontal cortex and hippocampus was negatively correlated with negative symptom scores in patients with schizophrenia, although there was no significant difference in BP between patients and controls. GABA(A)/BZ receptor including alpha5 subunit in the prefrontal cortex and hippocampus might be involved in the pathophysiology of negative symptoms of schizophrenia.
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Affiliation(s)
- Yoshiyuki Asai
- Molecular Neuroimaging Group, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba, 263-8555, Japan
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23
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Abstract
The ability of SPECT and PET to image specific biomolecules in the living brain provides a unique tool for clinical researchers. It is therefore not surprising that the use of neuroreceptor-imaging techniques has become more widespread over the past decade. This article reviews the application of these techniques to the study of schizophrenia. The design of neuroreceptor-imaging studies performed in the field of schizophrenia research can be broadly divided into two categories: (1) studies of pathophysiology and (2) studies of pharmacology. The former examines neuroreceptor and neurotransmitter parameters in individuals with schizophrenia compared to control subjects in order to provide a better understanding of the disease process. Studies of pharmacology seek to elucidate the mechanism of action for the treatments utilized in schizophrenia. This review will consider both studies of pathophysiology and pharmacology, with a discussion of the application of these techniques to drug development.
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Affiliation(s)
- W Gordon Frankle
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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Kiriyama T, Tanizawa E, Hirano M, Shinkai T, Asai H, Furiya Y, Ueno S. SPECT revealed cortical dysfunction in a patient who had genetically definite megalencephalic leukoencephalopathy with subcortical cysts. Clin Neurol Neurosurg 2007; 109:526-30. [PMID: 17507156 DOI: 10.1016/j.clineuro.2007.03.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Revised: 03/05/2007] [Accepted: 03/23/2007] [Indexed: 11/20/2022]
Abstract
We describe the findings on single photon emission computed tomography (SPECT) in a patient who had genetically definite megalencephalic leukoencephalopathy with subcortical cysts. Technetium-99m-ethyl cysteinate dimer SPECT revealed hypoperfusion in the cerebral white matter, which had shown high signal intensity on magnetic resonance imaging (MRI) T2 images. Hypoperfusion was also unexpectedly found in the frontal cortices, which showed no abnormalities on MRI. This frontal abnormality corresponded clinically to a low score on the frontal assessment battery. Decreased GABA receptor density as suggested by (123)I-Iomazenil SPECT provided further evidence of cortical neuron dysfunction. Although confirmation must await future larger-scale SPECT and functional studies, our findings suggest that SPECT can be used to non-invasively monitor in vivo cortical function in this disease.
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Affiliation(s)
- Takao Kiriyama
- Department of Neurology, Nara Medical University School of Medicine, Kashihara, Nara, Japan
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Kohno T, Shiga T, Kusumi I, Matsuyama T, Kageyama H, Katoh C, Koyama T, Tamaki N. Left temporal perfusion associated with suspiciousness score on the Brief Psychiatric Rating Scale in schizophrenia. Psychiatry Res 2006; 147:163-71. [PMID: 16959474 DOI: 10.1016/j.pscychresns.2006.01.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2005] [Revised: 01/25/2006] [Accepted: 01/29/2006] [Indexed: 11/21/2022]
Abstract
We evaluated the relationship between regional cerebral blood flow (rCBF) and clinical symptoms in patients with schizophrenia. Single photon emission computed tomography with N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) was used to study 29 patients with schizophrenia. Clinical symptoms were assessed using the Brief Psychiatric Rating Scale (BPRS). We examined the correlation between rCBF and each BPRS item score using Statistical Parametric Mapping software. Corrected P-values < 0.05 were considered as statistically significant. The suspiciousness score on the BPRS was positively correlated with rCBF in the left inferior temporal gyrus. There was no significant correlation between rCBF and any other items of the BPRS. There was no significant correlation between rCBF and chlorpromazine-equivalent dosage. This analysis permits the quantitative assessment of the severity of persecutory delusions in relation to left temporal perfusion in patients with schizophrenia.
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Affiliation(s)
- Tomoya Kohno
- Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan.
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26
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D'Souza DC, Gil RB, Zuzarte E, MacDougall LM, Donahue L, Ebersole JS, Boutros NN, Cooper T, Seibyl J, Krystal JH. gamma-Aminobutyric acid-serotonin interactions in healthy men: implications for network models of psychosis and dissociation. Biol Psychiatry 2006; 59:128-37. [PMID: 16140281 DOI: 10.1016/j.biopsych.2005.06.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Revised: 04/29/2005] [Accepted: 06/17/2005] [Indexed: 11/16/2022]
Abstract
BACKGROUND This study tested the hypothesis that deficits in gamma-aminobutyric acid type A (GABA(A)) receptor function might create a vulnerability to the psychotogenic and perceptual altering effects of serotonergic (5-HT(2A/2C)) receptor stimulation. The interactive effects of iomazenil, an antagonist and partial inverse agonist of the benzodiazepine site of the GABA(A) receptor complex, and m-chlorophenylpiperazine (m-CPP), a partial agonist of 5-HT(2A/2C) receptors, were studied in 23 healthy male subjects. METHODS Subjects underwent 4 days of testing, during which they received intravenous infusions of iomazenil/placebo followed by m-CPP/placebo in a double-blind, randomized crossover design. Behavioral, cognitive, and hormonal data were collected before drug infusions and periodically for 200 min after. RESULTS Iomazenil and m-CPP interacted in a synergistic manner to produce mild psychotic symptoms and perceptual disturbances without impairing cognition. Iomazenil and m-CPP increased anxiety in an additive fashion. Iomazenil and m-CPP interacted in a synergistic manner to increase serum cortisol. CONCLUSIONS Gamma-aminobutyric acid-ergic deficits might increase the vulnerability to the psychotomimetic and perceptual altering effects of serotonergic agents. These data suggest that interactions between GABA(A) and 5-HT systems might contribute to the pathophysiology of psychosis and dissociative-like perceptual states.
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Affiliation(s)
- Deepak Cyril D'Souza
- Schizophrenia Biological Research Center, West Haven Veterans Affairs Medical Center, West Haven, Connecticut, USA.
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Eells JB, Misler JA, Nikodem VM. Early postnatal isolation reduces dopamine levels, elevates dopamine turnover and specifically disrupts prepulse inhibition in Nurr1-null heterozygous mice. Neuroscience 2006; 140:1117-26. [PMID: 16690213 DOI: 10.1016/j.neuroscience.2005.12.065] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2005] [Revised: 11/28/2005] [Accepted: 12/07/2005] [Indexed: 11/27/2022]
Abstract
Sensorimotor gating is a phenomenon that is linked with dopamine neurotransmission in limbic and cortical areas, and disruption of sensorimotor gating has been consistently demonstrated in schizophrenia patients. The nuclear receptor Nurr1 is essential for development of dopamine neurons and, using Nurr1-null heterozygous mice, has been found to be important for normal dopamine neurotransmission as null heterozygous mice have reduced limbic and cortical dopamine levels and elevated open-field locomotor activity. The current investigation compared sensorimotor gating, as measured by prepulse inhibition of the acoustic startle response, in Nurr1 wild-type and null heterozygous mice. When mice were weaned between 19 and 21 days of age either into isolation or groups of three to five and tested 12 weeks later, prepulse inhibition was elevated in group-raised null heterozygous mice and significantly disrupted in isolated null heterozygous mice as compared with isolation-raised wild-type mice and group-raised null heterozygous mice. Isolation had no effect on prepulse inhibition in wild-type mice. Isolation reduced tissue dopamine levels and elevated dopamine turnover in the nucleus accumbens and striatum in both wild-type and null heterozygous mice. In the prefrontal cortex, isolation reduced dopamine and 3,4-dihydroxyphenylacetic acid levels in null heterozygous as compared with isolation-raised wild-type mice, whereas no differences were observed between group-raised wild-type and null heterozygous mice. Neither the null heterozygous genotype nor isolation had any effect on basal or stress-induced corticosterone levels. These data suggest that the Nurr1 null heterozygous genotype predisposes these mice to isolation-induced disruption of prepulse inhibition that may be related to the interactions between intrinsic deficiencies in dopamine neurotransmission as a result of the null heterozygous genotype and isolation-induced changes in dopamine neurotransmission. Post-weaning isolation of Nurr1 null heterozygous mice provides a model to explore the interactions of genetic predisposition and environment/neurodevelopment on dopamine function that has important relevance to neuropsychiatric disorders.
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Affiliation(s)
- J B Eells
- National Institute for Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 900 Rockville Pike, Bethesda, MD 20892, USA.
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28
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Frankle WG, Slifstein M, Talbot PS, Laruelle M. Neuroreceptor Imaging in Psychiatry: Theory and Applications. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2005; 67:385-440. [PMID: 16291028 DOI: 10.1016/s0074-7742(05)67011-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- W Gordon Frankle
- Departments of Psychiatry, Columbia University College of Physicians and Surgeons and New York State Psychiatric Institute, New York, New York 10032, USA
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29
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Fujita M, Southwick SM, Denucci CC, Zoghbi SS, Dillon MS, Baldwin RM, Bozkurt A, Kugaya A, Verhoeff NPLG, Seibyl JP, Innis RB. Central type benzodiazepine receptors in Gulf War veterans with posttraumatic stress disorder. Biol Psychiatry 2004; 56:95-100. [PMID: 15231441 DOI: 10.1016/j.biopsych.2004.03.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2003] [Revised: 02/25/2004] [Accepted: 03/17/2004] [Indexed: 11/30/2022]
Abstract
BACKGROUND A previous single photon emission computed tomography study showed decreased central type benzodiazepine receptors in the prefrontal cortex in Vietnam War veterans with posttraumatic stress disorder. To assess the generalizability of this finding to patients with more recent history, we studied central type benzodiazepine receptors in Gulf War veterans with posttraumatic stress disorder. METHODS Nineteen Gulf War veterans with posttraumatic stress disorder and 19 age-matched, healthy, nondeployed veterans participated in a single photon emission computed tomography study using [(123)I]iomazenil. Regional total distribution volume (V(T)') was compared between two groups using Statistical Parametric Mapping 99 (Wellcome Department of Imaging Neuroscience, London, United Kingdom) and volumes of interest analysis. RESULTS Benzodiazepine receptor levels did not show regional differences between the two groups, either with or without global normalization. Average difference in V(T)' was 2% across brain areas; however, by applying global normalization, V(T)' in the patient group showed significant negative correlation with childhood trauma scores in the right superior temporal gyrus. CONCLUSIONS Less severe symptoms and shorter duration of the illness in the current group than the prior one may be the source of the difference in the results of the two studies.
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Affiliation(s)
- Masahiro Fujita
- Department of Psychiatry, Yale University and Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, USA
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30
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Erritzoe D, Talbot P, Frankle WG, Abi-Dargham A. Positron emission tomography and single photon emission CT molecular imaging in schizophrenia. Neuroimaging Clin N Am 2003; 13:817-32. [PMID: 15024964 DOI: 10.1016/s1052-5149(03)00089-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We reviewed findings from PET and SPECT studies that have contributed to our understanding of the pathophysiology and treatment of schizophrenia. The most robust set of findings pertains to imaging of presynaptic dopaminergic function in the striatum. The results of these studies have been consistent in showing that schizophrenia, at least during episodes of illness exacerbation, is associated with increased activity of DA neurons; this increased presynaptic activity is associated with positive symptoms and good therapeutic response. Studies of cortical DA function are less numerous and less consistent. In the future, technical advances in PET instrumentation and radioligand development should contribute to a clarification of the role of prefrontal DA in the cognitive impairment that is presented by these patients. An important drawback of the literature in this field is the generally low number of subjects that are included in studies (typically less than 20 per group). Small samples are necessitated by the cost of these investigations, but also, in some instances, to the difficulty in recruiting appropriate clinical subjects (such as drug-free patients who have schizophrenia). In conditions that are characterized by marked heterogeneity, such as major depressive disorders, this factor is bound to yield divergent results across studies. Another source of discrepancy is the variety of technical approaches to data acquisition and analysis. For example, analytical methods range from "empirical" or "semiquantitative" (typically a region of interest to a region of reference ratio measured at one time point) to model-based methods that use an arterial input function. The limitations that are associated with empirical analytical methods might account for artifactual results, especially when the effect size of the between-group difference and the number of subjects are small [149]. In addressing these limitations it will be important to increase the availability of these techniques beyond a few academic centers, to promote multi-center studies in well-characterized populations, and to standardize analytical methods. Until recently, SPECT was the only widely available technique, and SPECT studies have provided a substantial contribution to this field. With the current increase in PET camera availability, the development of [18F]-based molecular imaging probes will provide unique opportunities for further dissemination of these techniques. The article reviewed seminal findings obtained with PET and SPECT molecular imaging of schizophrenia. These techniques do not play a major role in the diagnosis and treatment of this disorder, remain essentially research tools. The results that have been produced by this field to date suggest that PET will significantly contribute to unraveling the biologic bases of psychiatric disorders and may contribute to their clinical management. Moreover, it is foreseeable that PET will become increasingly involved in the development of new psychiatric medications. Expanding the availability of PET and the current radiopharmaceutical portfolio will be critical for these predictions to become reality.
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Affiliation(s)
- David Erritzoe
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York State Psychiatric Institute, 1051 Riverside Drive, Unit 31, New York, NY 10032, USA
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Kugaya A, Sanacora G, Verhoeff NPLG, Fujita M, Mason GF, Seneca NM, Bozkurt A, Khan SA, Anand A, Degen K, Charney DS, Zoghbi SS, Baldwin RM, Seibyl JP, Innis RB. Cerebral benzodiazepine receptors in depressed patients measured with [123I]iomazenil SPECT. Biol Psychiatry 2003; 54:792-9. [PMID: 14550678 DOI: 10.1016/s0006-3223(02)01788-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND A recent magnetic resonance spectroscopy (MRS) study revealed low gamma-aminobutyric acid (GABA) levels in the occipital cortex of depressed patients. No in vivo study has been reported to measure postsynaptic GABA receptors in the patients. METHODS Cortical benzodiazepine (BZ) binding to GABA(A) receptors was measured with [(123)I]iomazenil and single photon emission computed tomography in unmedicated patients with unipolar major depression (n = 13) and healthy subjects (n = 19). Group differences were evaluated by means of statistical parametric mapping (SPM) with partial volume correction for gray matter. Occipital GABA levels were determined by proton MRS in a subgroup (n = 6) of the patients. RESULTS No evidence of altered BZ binding was found in patients with depression compared with healthy control subjects in the SPM analysis. Although reduction in gray matter volume was observed in the frontal cortex and amygdala of the patients, partial volume correction of the atrophy did not change the result of unaltered BZ binding. GABA levels were found lower in the occipital cortex; however, BZ binding did not show significant relationship to GABA levels. CONCLUSIONS GABA(A) receptor binding measured in vivo with BZ radioligand binding are not altered in patients with depression.
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Affiliation(s)
- Akira Kugaya
- Department of Psychiatry, Yale University, New Haven, CT, USA
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Krystal JH, D'Souza DC, Mathalon D, Perry E, Belger A, Hoffman R. NMDA receptor antagonist effects, cortical glutamatergic function, and schizophrenia: toward a paradigm shift in medication development. Psychopharmacology (Berl) 2003; 169:215-33. [PMID: 12955285 DOI: 10.1007/s00213-003-1582-z] [Citation(s) in RCA: 398] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2003] [Accepted: 07/09/2003] [Indexed: 11/25/2022]
Abstract
There is an urgent need to improve the pharmacotherapy of schizophrenia despite the introduction of important new medications. New treatment insights may come from appreciating the therapeutic implications of model psychoses. In particular, basic and clinical studies have employed the N-methyl-D-aspartate (NMDA) glutamate receptor antagonist, ketamine, as a probe of NMDA receptor contributions to cognition and behavior. These studies illustrate a translational neuroscience approach for probing mechanistic hypotheses related to the neurobiology and treatment of schizophrenia and other disorders. Two particular pathophysiologic themes associated with schizophrenia, the disturbance of cortical connectivity and the disinhibition of glutamatergic activity may be modeled by the administration of NMDA receptor antagonists. The purpose of this review is to consider the possibility that agents that attenuate these two components of NMDA receptor antagonist response may play complementary roles in the treatment of schizophrenia.
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Affiliation(s)
- John H Krystal
- Schizophrenia Biological Research Center (116-A), VA Connecticut Healthcare System, 950 Campbell Ave., West Haven, CT 06516, USA.
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Oda K, Okubo Y, Ishida R, Murata Y, Ohta K, Matsuda T, Matsushima E, Ichimiya T, Suhara T, Shibuya H, Nishikawa T. Regional cerebral blood flow in depressed patients with white matter magnetic resonance hyperintensity. Biol Psychiatry 2003; 53:150-6. [PMID: 12547471 DOI: 10.1016/s0006-3223(02)01548-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND Functional neuroimaging studies have consistently demonstrated decreased regional cerebral blood flow (rCBF) or metabolism in the frontal lobe, temporal lobe, or anterior cingulate gyrus of depressed patients. On the other hand, white matter hyperintensity as defined by magnetic resonance imaging (MRI) has been the most consistently replicated finding in structural neuroimaging studies on depression; however, these functional and structural neuroimaging findings of depression have not been well integrated. We aimed to clarify the possible associations of MRI-defined subcortical hyperintensities with rCBF changes in depressed patients. METHODS Twelve depressed patients with subcortical hyperintensities defined by MRI, 11 depressed patients without MRI hyperintensities, and 25 healthy volunteers underwent 99mTc ECD SPECT. Group comparisons of their rCBF and correlation analysis between MRI hyperintensity and rCBF in patients were performed with a voxel-based analysis using statistical parametric mapping (SPM) software. RESULTS Depressed patients showed decreased rCBF compared with control subjects in the frontal lobe, temporal lobe, and anterior cingulate gyrus whether subcortical hyperintensity existed or not; however, the patients with MRI hyperintensity showed decreased rCBF in the thalamus, basal ganglia, and brainstem in addition to cortical areas. Further, the score for white matter hyperintensity correlated negatively with rCBF in subcortical brain structures, including the thalamus and right basal ganglia. CONCLUSION Our study indicates that depressed patients with MRI hyperintensities may have dysfunction in subcortical brain structures in addition to dysfunction in the fronto-temporal cortical structures.
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Affiliation(s)
- Kenji Oda
- Section of Psychiatry and Behavioral Science, Graduate School of MedicineTokyo Medical and Dental University, Tokyo, Japan
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Abstract
Neurotransmitter receptor systems have been the focus of intensive pharmacological research for more than 20 years for basic and applied scientific reasons, but only recently has there been a better understanding of their key features. One of these systems includes the type A receptor for the gamma-aminobutyric acid (GABA), which forms an integral anion channel from a pentameric subunit assembly and mediates most of the fast inhibitory neurotransmission in the adult vertebrate central nervous system. Up to now, depending on the definition, 16-19 mammalian subunits have been cloned and localized on different genes. Their assembly into proteins in a poorly defined stoichiometry forms the basis of functional and pharmacological GABA(A) receptor diversity, i.e. the receptor subtypes. The latter has been well documented in autoradiographic studies using ligands that label some of the receptors' various binding sites, corroborated by recombinant expression studies using the same tools. Significantly less heterogeneity has been found at the physiological level in native receptors, where the subunit combinations have been difficult to dissect. This review focuses on the characteristics, use and usefulness of various ligands and their binding sites to probe GABA(A) receptor properties and to gain insight into the biological function from fish to man and into evolutionary conserved GABA(A) receptor heterogeneity. We also summarize the properties of the novel mouse models created for the study of various brain functions and review the state-of-the-art imaging of brain GABA(A) receptors in various human neuropsychiatric conditions. The data indicate that the present ligands are only partly satisfactory tools and further ligands with subtype-selective properties are needed for imaging purposes and for confirming the behavioral and functional results of the studies presently carried out in gene-targeted mice with other species, including man.
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Affiliation(s)
- Esa R Korpi
- Department of Pharmacology and Clinical Pharmacology, University of Turku, Itäinen Pitkäkatu 4B, Finland.
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Verhoeff NP, Meyer JH, Kecojevic A, Hussey D, Lewis R, Tauscher J, Zipursky RB, Kapur S. A voxel-by-voxel analysis of [18F]setoperone PET data shows no substantial serotonin 5-HT(2A) receptor changes in schizophrenia. Psychiatry Res 2000; 99:123-35. [PMID: 11068194 DOI: 10.1016/s0165-1781(00)00198-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Several postmortem studies have reported regionally localized decreases in serotonin(2A) receptors (5-HT(2A)R) in schizophrenia. This was not confirmed by two recent [18F]setoperone positron emission tomography (PET) studies. In these two studies relatively large regions of interest (ROIs) were used; hence, 5-HT(2A)R changes may have been missed in some brain areas. Therefore, data from one study were analyzed on a voxel-by-voxel basis using Statistical Parametric Mapping (SPM). We also used this method to examine the relationship between 5-HT(2A)R binding potential (BP) and five PANSS-derived factors: negative, positive, activation, dysphoric and autistic preoccupation. Thirteen schizophrenic patients (10 antipsychotic-naïve, 3 antipsychotic-free; 11 M, 2 F; age 31+/-7 years) and 35 age-matched control subjects (15 M, 20 F; age 30+/-7 years) were scanned. The 5-HT(2A)R BP was determined for each voxel using the pseudoequilibrium ratio method on PET data obtained between 65 and 90 min after [18F]setoperone bolus injection. The resulting parametric 5-HT(2A)R BP images were spatially normalized using a ligand specific template. Analyses of covariance were done using SPM99 with age as covariate. In tests for the effect of schizophrenia and for partial correlations between 5-HT(2A)R BP and the five factors, corrected P values <0.05 at cluster or voxel level were considered significant. No significant differences were detected between patients and control subjects, and no significant correlations were observed between 5-HT(2A)R BP and any of the five factors. Thus, in agreement with the previous ROI studies, voxel-by-voxel analysis confirmed the lack of substantial 5-HT(2A)R BP differences between schizophrenic patients and control subjects.
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Affiliation(s)
- N P Verhoeff
- PET Centre and Schizophrenia and Continuing Care Division, Clarke Site, Centre for Addiction and Mental Health, University of Toronto, ON, M5T 1R8, Toronto, Canada.
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