1
|
Phan JA, Wong DF, Chang NHS, Kumakura Y, Bauer WR, Gjedde A. Transient equilibrium determination of dopamine D 2/D 3 receptor densities and affinities in brain. FRONTIERS IN NUCLEAR MEDICINE (LAUSANNE, SWITZERLAND) 2022; 2:1030387. [PMID: 36926525 PMCID: PMC10017089 DOI: 10.3389/fnume.2022.1030387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Long-term alteration of dopaminergic neurotransmission is known to modulate the D2/D3 receptor expression in the brain. The modulation can occur as a response to pathological processes or pharmacological intervention. The receptor density can be monitored by in vivo positron emission tomography (PET) of [11C] raclopride. To obtain accurate measurements of receptor-ligand interaction, it is essential to estimate binding parameters at true (if transient) equilibrium of bound and unbound ligand quantities. We designed this study as a comparison of two quantitative approaches to transient equilibrium, the TRansient EquilibriuM BoLus Estimation (TREMBLE) method and the Transient Equilibrium Model (TEM) method, to determine binding parameters at transient equilibrium with bolus injection of the radioligand. The data demonstrates that TREMBLE unlike TEM identified the time at which equilibrium existed. TREMBLE revealed that equilibrium prevailed at one or more times after bolus injection and identified differences of receptor density among regions such as putamen and caudate nucleus. We demonstrated that TREMBLE is a quantitative approach suitable for the study of pathophysiological conditions of certain types of neurotransmission the brain.
Collapse
Affiliation(s)
- Jenny-Ann Phan
- Department of Neurology, Gødstrup Hospital, Herning, Denmark
- NIDO - Centre for Research and Education, Gødstrup Hospital, Herning, Denmark
- Department of Neurology, Aarhus University, Aarhus, Denmark
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark
- Johns Hopkins Medical Institutions, Department of Radiology and Radiological Sciences, Division of Nuclear Medicine PET Center, Baltimore MD, United States
| | - Dean F. Wong
- Johns Hopkins Medical Institutions, Department of Radiology and Radiological Sciences, Division of Nuclear Medicine PET Center, Baltimore MD, United States
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, MO, United States
| | - Natalie H. S. Chang
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark
- Institute of Regional Health Research, University of Southern Denmark, Odense, Denmark
- Medical Spinal Research Unit, Spine Centre of Southern Denmark, University Hospital of Southern Denmark, Odense, Denmark
| | - Yoshitaka Kumakura
- Department of Diagnostic Radiology and Nuclear Medicine, Saitama Medical Center, Saitama Medical University, Moroyama, Japan
| | - William R. Bauer
- Translational Neuropsychiatry Unit, Department of Clinical Research, Aarhus University, Aarhus, Denmark
| | - Albert Gjedde
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark
- Johns Hopkins Medical Institutions, Department of Radiology and Radiological Sciences, Division of Nuclear Medicine PET Center, Baltimore MD, United States
- Translational Neuropsychiatry Unit, Department of Clinical Research, Aarhus University, Aarhus, Denmark
- Departments of Nuclear Medicine and Clinical Research, University of Southern Denmark and Odense University Hospital, Odense, Denmark
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
- Neuroscience Center, Tabriz University of Medical Sciences, Tabriz, Iran
| |
Collapse
|
2
|
Nwabufo CK, Aigbogun OP. Diagnostic and therapeutic agents that target alpha-synuclein in Parkinson's disease. J Neurol 2022; 269:5762-5786. [PMID: 35831620 PMCID: PMC9281355 DOI: 10.1007/s00415-022-11267-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 06/29/2022] [Accepted: 07/01/2022] [Indexed: 12/14/2022]
Abstract
The development of disease-modifying drugs and differential diagnostic agents is an urgent medical need in Parkinson’s disease. Despite the complex pathophysiological pathway, the misfolding of alpha-synuclein has been identified as a putative biomarker for detecting the onset and progression of the neurodegeneration associated with Parkinson’s disease. Identifying the most appropriate alpha-synuclein-based diagnostic modality with clinical translation will revolutionize the diagnosis of Parkinson’s. Likewise, molecules that target alpha-synuclein could alter the disease pathway that leads to Parkinson’s and may serve as first-in class therapeutics compared to existing treatment options such as levodopa and dopamine agonist that do not necessarily modify the disease pathway. Notwithstanding the promising benefits that alpha-synuclein presents to therapeutics and diagnostics development for Parkinson’s disease, finding ways to address potential challenges such as inadequate preclinical models, safety and efficacy will be paramount to achieving clinical translation. In this comprehensive review paper, we described the role of alpha-synuclein in the pathogenesis of Parkinson’s disease, as well as how its structure and function relationship delineate disease onset and progression. We further discussed different alpha-synuclein-based diagnostic modalities including biomolecular assays and molecular imaging. Finally, we presented current small molecules and biologics that are being developed as disease-modifying drugs or positron emission tomography imaging probes for Parkinson’s disease.
Collapse
Affiliation(s)
- Chukwunonso K Nwabufo
- Drug Discovery and Development Research Group, College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Canada. .,Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, M5S 3M2, Canada.
| | - Omozojie P Aigbogun
- Drug Discovery and Development Research Group, College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Canada.,Department of Chemistry, University of Saskatchewan, Saskatoon, Canada
| |
Collapse
|
3
|
Atlas of type 2 dopamine receptors in the human brain: Age and sex dependent variability in a large PET cohort. Neuroimage 2022; 255:119149. [PMID: 35367652 DOI: 10.1016/j.neuroimage.2022.119149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 03/22/2022] [Accepted: 03/24/2022] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The dopamine system contributes to a multitude of functions ranging from reward and motivation to learning and movement control, making it a key component in goal-directed behavior. Altered dopaminergic function is observed in neurological and psychiatric conditions. Numerous factors have been proposed to influence dopamine function, but due to small sample sizes and heterogeneous data analysis methods in previous studies their specific and joint contributions remain unresolved. METHODS In this cross-sectional register-based study we investigated how age, sex, body mass index (BMI), as well as cerebral hemisphere and regional volume influence striatal type 2 dopamine receptor (D2R) availability in the human brain. We analyzed a large historical dataset (n=156, 120 males and 36 females) of [11C]raclopride PET scans performed between 2004 and 2018. RESULTS Striatal D2R availability decreased through age for both sexes (2-5 % in striatal ROIs per 10 years) and was higher in females versus males throughout age (7-8% in putamen). BMI and striatal D2R availability were weakly associated. There was no consistent lateralization of striatal D2R. The observed effects were independent of regional volumes. These results were validated using two different spatial normalization methods, and the age and sex effects also replicated in an independent sample (n=135). CONCLUSIONS D2R availability is dependent on age and sex, which may contribute to the vulnerability of neurological and psychiatric conditions involving altering D2R expression.
Collapse
|
4
|
Kim S, Shin SH, Santangelo B, Veronese M, Kang SK, Lee JS, Cheon GJ, Lee W, Kwon JS, Howes OD, Kim E. Dopamine dysregulation in psychotic relapse after antipsychotic discontinuation: an [ 18F]DOPA and [ 11C]raclopride PET study in first-episode psychosis. Mol Psychiatry 2021; 26:3476-3488. [PMID: 32929214 DOI: 10.1038/s41380-020-00879-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 08/24/2020] [Accepted: 09/03/2020] [Indexed: 01/09/2023]
Abstract
Although antipsychotic drugs are effective for relieving the psychotic symptoms of first-episode psychosis (FEP), psychotic relapse is common during the course of the illness. While some FEPs remain remitted even without medication, antipsychotic discontinuation is regarded as the most common risk factor for the relapse. Considering the actions of antipsychotic drugs on presynaptic and postsynaptic dopamine dysregulation, this study evaluated possible mechanisms underlying relapse after antipsychotic discontinuation. Twenty five FEPs who were clinically stable and 14 matched healthy controls were enrolled. Striatal dopamine activity was assessed as Kicer value using [18F]DOPA PET before and 6 weeks after antipsychotic discontinuation. The D2/3 receptor availability was measured as BPND using [11C]raclopride PET after antipsychotic discontinuation. Healthy controls also underwent PET scans according to the corresponding schedule of the patients. Patients were monitored for psychotic relapse during 12 weeks after antipsychotic discontinuation. 40% of the patients showed psychotic relapse after antipsychotic discontinuation. The change in Kicer value over time significantly differed between relapsed, non-relapsed patients and healthy controls (Week*Group: F = 4.827, df = 2,253.193, p = 0.009). In relapsed patients, a significant correlation was found between baseline striatal Kicer values and time to relapse after antipsychotic discontinuation (R2 = 0.518, p = 0.018). BPND were not significantly different between relapsed, non-relapsed patients and healthy controls (F = 1.402, df = 2,32.000, p = 0.261). These results suggest that dysfunctional dopamine autoregulation might precipitate psychotic relapse after antipsychotic discontinuation in FEP. This finding could be used for developing a strategy for the prevention of psychotic relapse related to antipsychotic discontinuation.
Collapse
Affiliation(s)
- Seoyoung Kim
- Department of Psychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, Republic of Korea
| | - Sang Ho Shin
- Department of Psychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, Republic of Korea
| | - Barbara Santangelo
- Centre for Neuroimaging Science, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Mattia Veronese
- Centre for Neuroimaging Science, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Seung Kwan Kang
- Department of Nuclear Medicine, College of Medicine, Seoul National University, Seoul, Republic of Korea.,Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Jae Sung Lee
- Department of Nuclear Medicine, College of Medicine, Seoul National University, Seoul, Republic of Korea.,Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Gi Jeong Cheon
- Department of Nuclear Medicine, College of Medicine, Seoul National University, Seoul, Republic of Korea.,Institute of Radiation Medicine, College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Woojoo Lee
- Department of Public Health Science, Graduate School of Public Health, Seoul National University, Seoul, Republic of Korea
| | - Jun Soo Kwon
- Department of Psychiatry, College of Medicine, Seoul National University, Seoul, Republic of Korea.,Department of Brain & Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - Oliver D Howes
- Department of Psychosis studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,Psychiatric Imaging, Medical Research Council Clinical Sciences Centre, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Euitae Kim
- Department of Psychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, Republic of Korea. .,Department of Psychiatry, College of Medicine, Seoul National University, Seoul, Republic of Korea. .,Department of Brain & Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea.
| |
Collapse
|
5
|
Prasad K, de Vries EFJ, Elsinga PH, Dierckx RAJO, van Waarde A. Allosteric Interactions between Adenosine A 2A and Dopamine D 2 Receptors in Heteromeric Complexes: Biochemical and Pharmacological Characteristics, and Opportunities for PET Imaging. Int J Mol Sci 2021; 22:ijms22041719. [PMID: 33572077 PMCID: PMC7915359 DOI: 10.3390/ijms22041719] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 12/17/2022] Open
Abstract
Adenosine and dopamine interact antagonistically in living mammals. These interactions are mediated via adenosine A2A and dopamine D2 receptors (R). Stimulation of A2AR inhibits and blockade of A2AR enhances D2R-mediated locomotor activation and goal-directed behavior in rodents. In striatal membrane preparations, adenosine decreases both the affinity and the signal transduction of D2R via its interaction with A2AR. Reciprocal A2AR/D2R interactions occur mainly in striatopallidal GABAergic medium spiny neurons (MSNs) of the indirect pathway that are involved in motor control, and in striatal astrocytes. In the nucleus accumbens, they also take place in MSNs involved in reward-related behavior. A2AR and D2R co-aggregate, co-internalize, and co-desensitize. They are at very close distance in biomembranes and form heteromers. Antagonistic interactions between adenosine and dopamine are (at least partially) caused by allosteric receptor–receptor interactions within A2AR/D2R heteromeric complexes. Such interactions may be exploited in novel strategies for the treatment of Parkinson’s disease, schizophrenia, substance abuse, and perhaps also attention deficit-hyperactivity disorder. Little is known about shifting A2AR/D2R heteromer/homodimer equilibria in the brain. Positron emission tomography with suitable ligands may provide in vivo information about receptor crosstalk in the living organism. Some experimental approaches, and strategies for the design of novel imaging agents (e.g., heterobivalent ligands) are proposed in this review.
Collapse
Affiliation(s)
- Kavya Prasad
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
- Correspondence: (K.P.); (A.v.W.); Tel.: +31-50-3613215
| | - Erik F. J. de Vries
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
| | - Philip H. Elsinga
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
| | - Rudi A. J. O. Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
- Department of Diagnostic Sciences, Ghent University Faculty of Medicine and Health Sciences, C.Heymanslaan 10, 9000 Gent, Belgium
| | - Aren van Waarde
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
- Correspondence: (K.P.); (A.v.W.); Tel.: +31-50-3613215
| |
Collapse
|
6
|
Cumming P, Gründer G, Brinson Z, Wong DF. Applications, Advances, and Limitations of Molecular Imaging of Brain Receptors. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.00063-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
|
7
|
Cumming P, Abi-Dargham A, Gründer G. Molecular imaging of schizophrenia: Neurochemical findings in a heterogeneous and evolving disorder. Behav Brain Res 2020; 398:113004. [PMID: 33197459 DOI: 10.1016/j.bbr.2020.113004] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/22/2020] [Accepted: 10/31/2020] [Indexed: 02/07/2023]
Abstract
The past four decades have seen enormous efforts placed on a search for molecular markers of schizophrenia using positron emission tomography (PET) and single photon emission computed tomography (SPECT). In this narrative review, we cast a broad net to define and summarize what researchers have learned about schizophrenia from molecular imaging studies. Some PET studies of brain energy metabolism with the glucose analogue FDGhave have shown a hypofrontality defect in patients with schizophrenia, but more generally indicate a loss of metabolic coherence between different brain regions. An early finding of significantly increased striatal trapping of the dopamine synthesis tracer FDOPA has survived a meta-analysis of many replications, but the increase is not pathognomonic of the disorder, since one half of patients have entirely normal dopamine synthesis capacity. Similarly, competition SPECT studies show greater basal and amphetamine-evoked dopamine occupancy at post-synaptic dopamine D2/3 receptors in patients with schizophrenia, but the difference is likewise not pathognomonic. We thus propose that molecular imaging studies of brain dopamine indicate neurochemical heterogeneity within the diagnostic entity of schizophrenia. Occupancy studies have established the relevant target engagement by antipsychotic medications at dopamine D2/3 receptors in living brain. There is evidence for elevated frontal cortical dopamine D1 receptors, especially in relation to cognitive deficits in schizophrenia. There is a general lack of consistent findings of abnormalities in serotonin markers, but some evidence for decreased levels of nicotinic receptors in patients. There are sparse and somewhat inconsistent findings of reduced binding of muscarinic, glutamate, and opioid receptors ligands, inconsistent findings of microglial activation, and very recently, evidence of globally reduced levels of synaptic proteins in brain of patients. One study reports a decline in histone acetylase binding that is confined to the dorsolateral prefrontal cortex. In most contexts, the phase of the disease and effects of past or present medication can obscure or confound PET and SPECT findings in schizophrenia.
Collapse
Affiliation(s)
- Paul Cumming
- Department of Nuclear Medicine, Inselspital, Bern University, Bern, Switzerland; School of Psychology and Counselling, Queensland University of Technology, Brisbane, Australia.
| | - Anissa Abi-Dargham
- Stony Brook University, Renaissance School of Medicine, Stony Brook, New York, USA
| | - Gerhard Gründer
- Central Institute of Mental Health, Department of Molecular Neuroimaging, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| |
Collapse
|
8
|
Nishibe H, Tateno A, Sakayori T, Yamamoto M, Kim W, Kakuyama H, Okubo Y. Striatal Dopamine D2 Receptor Occupancy Induced by Daily Application of Blonanserin Transdermal Patches: Phase II Study in Japanese Patients With Schizophrenia. Int J Neuropsychopharmacol 2020; 24:108-117. [PMID: 32936897 PMCID: PMC7883894 DOI: 10.1093/ijnp/pyaa071] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 08/30/2020] [Accepted: 09/15/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Transdermal antipsychotic patch formulations offer potential benefits, including improved adherence. This study investigated the striatal dopamine D2 receptor occupancy with daily blonanserin transdermal patch application. METHODS This open-label, phase II study enrolled 18 Japanese outpatients (20 to <65 years) with schizophrenia (DSM-IV-TR criteria; total Positive and Negative Syndrome Scale score <120 at screening) treated with blonanserin 8-mg or 16-mg tablets. Patients continued tablets for 2-4 weeks at their current dose and were then assigned to once-daily blonanserin patches (10/20/40/60/80 mg daily) for 2-4 weeks based on the oral dose. [11C]raclopride positron emission tomography scanning determined blonanserin striatal dopamine D2 receptor occupancy (primary endpoint). Secondary endpoints included assessment of receptor occupancy by dose, changes in Positive and Negative Syndrome Scale and Clinical Global Impressions-Severity of Illness-Severity scores, patient attitudes towards adherence, and patch adhesiveness. RESULTS Of 18 patients who started the blonanserin tablet treatment period, 14 patients completed treatment. Mean D2 receptor occupancy for blonanserin tablets 8 mg/d (59.2%, n = 5) and 16 mg/d (66.3%, n = 9) was within the values for blonanserin patches: 10 mg/d (33.3%, n = 3), 20 mg/d (29.9%, n = 2), 40 mg/d (61.2%, n = 3), 60 mg/d (59.0%, n = 3), and 80 mg/d (69.9%, n = 3). Occupancy generally increased with increasing blonanserin dose for both formulations with the half maximal receptor occupancy for tablets and patches associated with doses of 6.9 mg/d and 31.9 mg/d, respectively. Diurnal variability in occupancy was lower during transdermal patch treatment than during tablet treatment. Blonanserin transdermal patches were well tolerated with no major safety concerns. CONCLUSIONS Blonanserin patches (40/80 mg/d) have lower diurnal variability in occupancy than blonanserin tablets (8/16 mg/d), and patches at doses of 40 mg/d and 80 mg/d appear to be a suitable alternative for blonanserin tablets at doses of 8 mg/d and 16 mg/d, respectively. Blonanserin patches represent a potential new treatment option for patients with schizophrenia. TRIAL REGISTRY JAPIC Clinical Trials Information registry (www.clinicaltrials.jp; JapicCTI-No: JapicCTI-121914).
Collapse
Affiliation(s)
- Hironori Nishibe
- Clinical Pharmacology Group, Clinical Research, Drug Development Division, Sumitomo Dainippon Pharma Co., Ltd., Tokyo, Japan,Correspondence: Hironori Nishibe, MS, Sumitomo Dainippon Pharma Co., Ltd., 13-1, Kyobashi 1-chome, Chuo-ku, Tokyo 104–8356, Japan ()
| | - Amane Tateno
- Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan
| | - Takeshi Sakayori
- Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan
| | | | - WooChan Kim
- Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan
| | - Hiroyoshi Kakuyama
- Clinical Pharmacology Group, Clinical Research, Drug Development Division, Sumitomo Dainippon Pharma Co., Ltd., Tokyo, Japan
| | - Yoshiro Okubo
- Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan
| |
Collapse
|
9
|
Abstract
SummaryThe prolactin (PRL) responses to 5 mg im haloperidol were assessed in the drug-free state and after one month treatment with neuroleptics in 14 male schizophrenic patients who had never received drug treatment, and in 20 male patients who had discontinued their neuroleptic treatment for periods of two months to one year. Drug experienced patients showed lower PRL increases after acute haloperidol (mean 31.7 ng/ml) than drug-naive patients (mean responses 43.4 ng/ml). After treatment with neuroleptics in doses appropriate for the best clinical response, the baseline PRL levels were similar in the two groups, and im haloperidol did not cause any further PRL increases. The results provide evidence that after discontinuation of neuroleptics, the hypothalamic-pituitary dopamine receptors are subsensitive, and remain in that state for long periods of time.
Collapse
|
10
|
Wulff S, Nielsen MØ, Rostrup E, Svarer C, Jensen LT, Pinborg L, Glenthøj BY. The relation between dopamine D 2 receptor blockade and the brain reward system: a longitudinal study of first-episode schizophrenia patients. Psychol Med 2020; 50:220-228. [PMID: 30642415 DOI: 10.1017/s0033291718004099] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Psychotic symptoms have been linked to salience abnormalities in the brain reward system, perhaps caused by a dysfunction of the dopamine neurotransmission in striatal regions. Blocking dopamine D2 receptors dampens psychotic symptoms and normalises reward disturbances, but a direct relationship between D2 receptor blockade, normalisation of reward processing and symptom improvement has not yet been demonstrated. The current study examined the association between blockade of D2 receptors in the caudate nucleus, alterations in reward processing and the psychopathology in a longitudinal study of antipsychotic-naïve first-episode schizophrenia patients. METHODS Twenty-two antipsychotic-naïve first-episode schizophrenia patients (10 males, mean age 23.3) and 23 healthy controls (12 males, mean age 23.5) were examined with single-photon emission computed tomography using 123I-labelled iodobenzamide. Reward disturbances were measured with functional magnetic resonance imaging (fMRI) using a modified version of the monetary-incentive-delay task. Patients were assessed before and after 6 weeks of treatment with amisulpride. RESULTS In line with previous results, patients had a lower fMRI response at baseline (0.2 ± 0.5 v. 0.7 ± 0.6; p = 0.008), but not at follow-up (0.5 ± 0.6 v. 0.6 ± 0.7), and a change in the fMRI signal correlated with improvement in Positive and Negative Syndrome Scale positive symptoms (ρ = -0.435, p = 0.049). In patients responding to treatment, a correlation between improvement in the fMRI signal and receptor occupancy was found (ρ = 0.588; p = 0.035). CONCLUSION The results indicate that salience abnormalities play a role in the reward system in schizophrenia. In patients responding to a treatment-induced blockade of dopamine D2 receptors, the psychotic symptoms may be ameliorated by normalising salience abnormalities in the reward system.
Collapse
Affiliation(s)
- Sanne Wulff
- Center for Neuropsychiatric Schizophrenia Research and Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research, Mental Health Centre Glostrup, University of Copenhagen, Glostrup, Denmark
| | - Mette Ødegaard Nielsen
- Center for Neuropsychiatric Schizophrenia Research and Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research, Mental Health Centre Glostrup, University of Copenhagen, Glostrup, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, København, Denmark
| | - Egill Rostrup
- Center for Neuropsychiatric Schizophrenia Research and Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research, Mental Health Centre Glostrup, University of Copenhagen, Glostrup, Denmark
- Department of Clinical Physiology, Functional Imaging Unit, Nuclear Medicine and PET, Rigshospitalet Glostrup, University of Copenhagen, København, Denmark
| | - Claus Svarer
- Neurobiology Research Unit, Rigshospitalet, University of Copenhagen, København, Denmark
| | - Lars Thorbjørn Jensen
- Department of Clinical Physiology and Nuclear Medicine, Herlev Hospital, University of Copenhagen, Herlev, Denmark
| | - Lars Pinborg
- Neurobiology Research Unit, Rigshospitalet, University of Copenhagen, København, Denmark
| | - Birte Yding Glenthøj
- Center for Neuropsychiatric Schizophrenia Research and Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research, Mental Health Centre Glostrup, University of Copenhagen, Glostrup, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, København, Denmark
| |
Collapse
|
11
|
Andrews MG, Nowakowski TJ. Human brain development through the lens of cerebral organoid models. Brain Res 2019; 1725:146470. [PMID: 31542572 PMCID: PMC6887101 DOI: 10.1016/j.brainres.2019.146470] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/21/2019] [Accepted: 09/18/2019] [Indexed: 01/01/2023]
Abstract
The brain is one of the most complex organs in the body, which emerges from a relatively simple set of basic 'building blocks' during early development according to complex cellular and molecular events orchestrated through a set of inherited instructions. Innovations in stem cell technologies have enabled modelling of neural cells using two- and three-dimensional cultures. In particular, cerebral ('brain') organoids have taken the center stage of brain development models that have the potential for providing meaningful insight into human neurodevelopmental and neurological disorders. We review the current understanding of cellular events during human brain organogenesis, and the events occurring during cerebral organoid differentiation. We highlight the strengths and weaknesses of this experimental model system. In particular, we explain evidence that organoids can mimic many aspects of early neural development, including neural induction, patterning, and broad neurogenesis and gliogenesis programs, offering the opportunity to study genetic regulation of these processes in a human context. Several shortcomings of the current culture methods limit the utility of cerebral organoids to spontaneously give rise to many important cell types, and to model higher order features of tissue organization. We suggest that future studies aim to improve these features in order to make them better models for the study of laminar organization, circuit formation and how disruptions of these processes relate to disease.
Collapse
Affiliation(s)
- Madeline G Andrews
- Department of Neurology, University of California, San Francisco, CA, USA; The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA, USA.
| | - Tomasz J Nowakowski
- Department of Anatomy, University of California, San Francisco, CA, USA; Department of Psychiatry, University of California, San Francisco, CA, USA; Chan Zuckerberg Biohub, San Francisco, CA, USA.
| |
Collapse
|
12
|
Fountoulakis KN, Dragioti E, Theofilidis AT, Wikilund T, Atmatzidis X, Nimatoudis I, Thys E, Wampers M, Hranov L, Hristova T, Aptalidis D, Milev R, Iftene F, Spaniel F, Knytl P, Furstova P, From T, Karlsson H, Walta M, Salokangas RKR, Azorin JM, Bouniard J, Montant J, Juckel G, Haussleiter IS, Douzenis A, Michopoulos I, Ferentinos P, Smyrnis N, Mantonakis L, Nemes Z, Gonda X, Vajda D, Juhasz A, Shrivastava A, Waddington J, Pompili M, Comparelli A, Corigliano V, Rancans E, Navickas A, Hilbig J, Bukelskis L, Injac Stevovic L, Vodopic S, Esan O, Oladele O, Osunbote C, Rybakowski JΚ, Wojciak P, Domowicz K, Figueira ML, Linhares L, Crawford J, Panfil AL, Smirnova D, Izmailova O, Lecic-Tosevski D, Temmingh H, Howells F, Bobes J, Garcia-Portilla MP, García-Alvarez L, Erzin G, Karadağ H, De Sousa A, Bendre A, Hoschl C, Bredicean C, Papava I, Vukovic O, Pejuskovic B, Russell V, Athanasiadis L, Konsta A, Stein D, Berk M, Dean O, Tandon R, Kasper S, De Hert. M. Staging of Schizophrenia With the Use of PANSS: An International Multi-Center Study. Int J Neuropsychopharmacol 2019; 22:681-697. [PMID: 31563956 PMCID: PMC6872964 DOI: 10.1093/ijnp/pyz053] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 07/19/2019] [Accepted: 09/25/2019] [Indexed: 12/30/2022] Open
Abstract
INTRODUCTION A specific clinically relevant staging model for schizophrenia has not yet been developed. The aim of the current study was to evaluate the factor structure of the PANSS and develop such a staging method. METHODS Twenty-nine centers from 25 countries contributed 2358 patients aged 37.21 ± 11.87 years with schizophrenia. Analysis of covariance, Exploratory Factor Analysis, Discriminant Function Analysis, and inspection of resultant plots were performed. RESULTS Exploratory Factor Analysis returned 5 factors explaining 59% of the variance (positive, negative, excitement/hostility, depression/anxiety, and neurocognition). The staging model included 4 main stages with substages that were predominantly characterized by a single domain of symptoms (stage 1: positive; stages 2a and 2b: excitement/hostility; stage 3a and 3b: depression/anxiety; stage 4a and 4b: neurocognition). There were no differences between sexes. The Discriminant Function Analysis developed an algorithm that correctly classified >85% of patients. DISCUSSION This study elaborates a 5-factor solution and a clinical staging method for patients with schizophrenia. It is the largest study to address these issues among patients who are more likely to remain affiliated with mental health services for prolonged periods of time.
Collapse
Affiliation(s)
- Konstantinos N Fountoulakis
- 3rd Department of Psychiatry, Faculty of Medicine, School of Health Sciences, Aristotle University of Thessaloniki,Greece,Correspondence to: Konstantinos N. Fountoulakis, 6, Odysseos str (1 Parodos Ampelonon str.), 55535 Pylaia Thessaloniki, Greece ()
| | - Elena Dragioti
- Department of Medical and Health Sciences (IMH), Faculty of Health Sciences, Linköping University, Linköping, Sweden,Hallunda Psychiatric Outpatient Clinic, Stockholm Psychiatric Southwest Clinic, Karolinska Huddinge University Hospital,Sweden
| | - Antonis T Theofilidis
- 3rd Department of Psychiatry, Faculty of Medicine, School of Health Sciences, Aristotle University of Thessaloniki,Greece
| | - Tobias Wikilund
- Department of Medical and Health Sciences (IMH), Faculty of Health Sciences, Linköping University, Linköping, Sweden,Hallunda Psychiatric Outpatient Clinic, Stockholm Psychiatric Southwest Clinic, Karolinska Huddinge University Hospital,Sweden
| | - Xenofon Atmatzidis
- Department of Medical and Health Sciences (IMH), Faculty of Health Sciences, Linköping University, Linköping, Sweden,Hallunda Psychiatric Outpatient Clinic, Stockholm Psychiatric Southwest Clinic, Karolinska Huddinge University Hospital,Sweden
| | - Ioannis Nimatoudis
- 3rd Department of Psychiatry, Faculty of Medicine, School of Health Sciences, Aristotle University of Thessaloniki,Greece
| | - Erik Thys
- University Psychiatric Centre KU Leuven, Kortenberg and Department of Neurosciences KU, Leuven, Belgium
| | - Martien Wampers
- University Psychiatric Centre KU Leuven, Kortenberg and Department of Neurosciences KU, Leuven, Belgium
| | - Luchezar Hranov
- University Multiprofile Hospital for Active Treatment in Neurology and Psychiatry “Sveti Naum”, Sofia, Bulgaria
| | - Trayana Hristova
- University Multiprofile Hospital for Active Treatment in Neurology and Psychiatry “Sveti Naum”, Sofia, Bulgaria
| | - Daniil Aptalidis
- University Multiprofile Hospital for Active Treatment in Neurology and Psychiatry “Sveti Naum”, Sofia, Bulgaria
| | - Roumen Milev
- Department of Psychiatry, Queen’s University, Providence Care Hospital, Kingston, Ontario, Canada
| | - Felicia Iftene
- Department of Psychiatry, Queen’s University, Providence Care Hospital, Kingston, Ontario, Canada
| | - Filip Spaniel
- National Institute of Mental Health, Klecany, Czech Republic
| | - Pavel Knytl
- National Institute of Mental Health, Klecany, Czech Republic
| | - Petra Furstova
- National Institute of Mental Health, Klecany, Czech Republic
| | - Tiina From
- Department of Psychiatry, University of Turku, Turku, Finland
| | - Henry Karlsson
- Department of Psychiatry, University of Turku, Turku, Finland
| | - Maija Walta
- Department of Psychiatry, University of Turku, Turku, Finland
| | | | - Jean-Michel Azorin
- Department of Psychiatry, Sainte Marguerite University Hospital, Marseille, France,Timone Institute of Neuroscience, CNRS and Aix-Marseille University, Marseille, France
| | - Justine Bouniard
- Department of Psychiatry, Sainte Marguerite University Hospital, Marseille, France,Timone Institute of Neuroscience, CNRS and Aix-Marseille University, Marseille, France
| | - Julie Montant
- Department of Psychiatry, Sainte Marguerite University Hospital, Marseille, France,Timone Institute of Neuroscience, CNRS and Aix-Marseille University, Marseille, France
| | - Georg Juckel
- Department of Psychiatry, Ruhr University Bochum, LWL-University Hospital, Bochum, Germany
| | - Ida S Haussleiter
- Department of Psychiatry, Ruhr University Bochum, LWL-University Hospital, Bochum, Germany
| | - Athanasios Douzenis
- 2nd Department of Psychiatry, National and Kapodistrian University of Athens, Athens, Greece
| | - Ioannis Michopoulos
- 2nd Department of Psychiatry, National and Kapodistrian University of Athens, Athens, Greece
| | - Panagiotis Ferentinos
- 2nd Department of Psychiatry, National and Kapodistrian University of Athens, Athens, Greece
| | - Nikolaos Smyrnis
- Department of Psychiatry, National and Kapodistrian University of Athens School of Medicine, Eginition Hospital, Athens, Greece
| | - Leonidas Mantonakis
- Department of Psychiatry, National and Kapodistrian University of Athens School of Medicine, Eginition Hospital, Athens, Greece
| | | | - Xenia Gonda
- Department of Psychiatry and Psychotherapy, Semmelweis University, Budapest, Hungary
| | - Dora Vajda
- Department of Psychiatry and Psychotherapy, Semmelweis University, Budapest, Hungary
| | - Anita Juhasz
- Department of Psychiatry and Psychotherapy, Semmelweis University, Budapest, Hungary
| | | | - John Waddington
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Maurizio Pompili
- Department of Neurosciences, Mental Health and Sensory Organs, Suicide Prevention Center, Sant’Andrea Hospital, Sapienza University of Rome, Rome, Italy
| | - Anna Comparelli
- Department of Neurosciences, Mental Health and Sensory Organs, Suicide Prevention Center, Sant’Andrea Hospital, Sapienza University of Rome, Rome, Italy
| | - Valentina Corigliano
- Department of Neurosciences, Mental Health and Sensory Organs, Suicide Prevention Center, Sant’Andrea Hospital, Sapienza University of Rome, Rome, Italy
| | - Elmars Rancans
- Department of Psychiatry and Narcology, Riga Stradins University, Riga, Latvia
| | - Alvydas Navickas
- Clinic of Psychiatric, Faculty of Medicine, Vilnius University, Vilnius, Lithuania,Psychosocial Rehabilitation Department of the Vilnius Mental Health Center, Department for Psychosis Treatment of the Vilnius Mental Health Center, Vilnius, Lithuania
| | - Jan Hilbig
- Clinic of Psychiatric, Faculty of Medicine, Vilnius University, Vilnius, Lithuania,Psychosocial Rehabilitation Department of the Vilnius Mental Health Center, Department for Psychosis Treatment of the Vilnius Mental Health Center, Vilnius, Lithuania
| | - Laurynas Bukelskis
- Clinic of Psychiatric, Faculty of Medicine, Vilnius University, Vilnius, Lithuania,Psychosocial Rehabilitation Department of the Vilnius Mental Health Center, Department for Psychosis Treatment of the Vilnius Mental Health Center, Vilnius, Lithuania
| | - Lidija Injac Stevovic
- Clinical Department of Psychiatry, Clinical Centre of Montenegro, Podgorica, Montenegro,Department of Psychiatry, School of Medicine, University of Montenegro, Dzona Dzeksona bb, Podgorica, Montenegro,Clinical Department of Neurology, Clinical Centre of Montenegro, Dzona Dzeksona bb, Podgorica, Montenegro
| | - Sanja Vodopic
- Clinical Department of Psychiatry, Clinical Centre of Montenegro, Podgorica, Montenegro,Department of Psychiatry, School of Medicine, University of Montenegro, Dzona Dzeksona bb, Podgorica, Montenegro,Clinical Department of Neurology, Clinical Centre of Montenegro, Dzona Dzeksona bb, Podgorica, Montenegro
| | - Oluyomi Esan
- Department of Psychiatry, College of Medicine, University of Ibadan,Nigeria
| | - Oluremi Oladele
- Department of Psychiatry, College of Medicine, University of Ibadan,Nigeria
| | | | - Janusz Κ Rybakowski
- Department of Adult Psychiatry, Poznan University of Medical Sciences, Poznan, Poland
| | - Pawel Wojciak
- Department of Adult Psychiatry, Poznan University of Medical Sciences, Poznan, Poland
| | - Klaudia Domowicz
- Department of Adult Psychiatry, Poznan University of Medical Sciences, Poznan, Poland
| | - Maria Luisa Figueira
- Department of Psychiatry and Mental Health, Santa Maria University Hospital, Lisbon, Portugal
| | - Ludgero Linhares
- Department of Psychiatry and Mental Health, Santa Maria University Hospital, Lisbon, Portugal
| | - Joana Crawford
- Department of Psychiatry and Mental Health, Santa Maria University Hospital, Lisbon, Portugal
| | | | - Daria Smirnova
- Samara State Medical University, Department of Psychiatry, Samara Psychiatric Hospital, Inpatient Unit, Russia
| | - Olga Izmailova
- Samara State Medical University, Department of Psychiatry, Samara Psychiatric Hospital, Inpatient Unit, Russia
| | - Dusica Lecic-Tosevski
- Institute of Mental Health, Belgrade, Serbia,Serbian Academy of Sciences and Arts, Belgrade, Serbia
| | - Henk Temmingh
- Department of Psychiatry and Mental Health, University of Cape Town Cape Town, Western Cape, South Africa
| | - Fleur Howells
- Department of Psychiatry and Mental Health, University of Cape Town Cape Town, Western Cape, South Africa
| | - Julio Bobes
- Department of Psychiatry, University of Oviedo and Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Oviedo, Spain
| | - Maria Paz Garcia-Portilla
- Department of Psychiatry, University of Oviedo and Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Oviedo, Spain
| | - Leticia García-Alvarez
- Department of Psychiatry, University of Oviedo and Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Oviedo, Spain
| | - Gamze Erzin
- Psychiatry Department, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey
| | - Hasan Karadağ
- Psychiatry Department, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey
| | - Avinash De Sousa
- Department of Psychiatry Lokmanya Tilak Municipal Medical College Mumbai, India
| | - Anuja Bendre
- Department of Psychiatry Lokmanya Tilak Municipal Medical College Mumbai, India
| | - Cyril Hoschl
- National Institute of Mental Health, Klecany, Czech Republic
| | | | - Ion Papava
- University of Medicine and Pharmacy of Timisoara, Romania
| | - Olivera Vukovic
- Institute of Mental Health, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Bojana Pejuskovic
- Department of Psychiatry, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland
| | - Vincent Russell
- Department of Psychiatry, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland
| | - Loukas Athanasiadis
- 1st Department of Psychiatry, Faculty of Medicine, School of Health Sciences, Aristotle University of Thessaloniki, Greece
| | - Anastasia Konsta
- 1st Department of Psychiatry, Faculty of Medicine, School of Health Sciences, Aristotle University of Thessaloniki, Greece
| | - Dan Stein
- MRC Unit on Risk and Resilience in Mental Disorders, Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
| | - Michael Berk
- Deakin University, IMPACT Strategic Research Centre, School of Medicine, Barwon Health, Geelong, Australia,Orygen, The National Centre of Excellence in Youth Mental Health and the Centre for Youth Mental Health, the Florey Institute for Neuroscience and Mental Health and the Department of Psychiatry, University of Melbourne, Parkville, Australia
| | - Olivia Dean
- Deakin University, School of Medicine, IMPACT Strategic Research Centre, Barwon Health, Geelong, Australia
| | - Rajiv Tandon
- Department of Psychiatry, University of Florida, ***, FL
| | - Siegfried Kasper
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Marc De Hert.
- University Psychiatric Centre KU Leuven, Kortenberg and Department of Neurosciences KU, Leuven, Belgium
| |
Collapse
|
13
|
Nikolaus S, Mamlins E, Hautzel H, Müller HW. Acute anxiety disorder, major depressive disorder, bipolar disorder and schizophrenia are related to different patterns of nigrostriatal and mesolimbic dopamine dysfunction. Rev Neurosci 2019; 30:381-426. [PMID: 30269107 DOI: 10.1515/revneuro-2018-0037] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 06/30/2018] [Indexed: 11/15/2022]
Abstract
Dopamine (DA) receptor and transporter dysfunctions play a major role in the pathophysiology of neuropsychiatric diseases including anxiety disorder (AD), major depressive disorder (MDD), bipolar disorder (BD) in the manic (BDman) or depressive (BDdep) state and schizophrenia (SZ). We performed a PUBMED search, which provided a total of 239 in vivo imaging studies with either positron emission tomography (PET) or single-proton emission computed tomography (SPECT). In these studies, DA transporter binding, D1 receptor (R) binding, D2R binding, DA synthesis and/or DA release in patients with the primary diagnosis of acute AD (n=310), MDD (n=754), BDman (n=15), BDdep (n=49) or SZ (n=1532) were compared to healthy individuals. A retrospective analysis revealed that AD, MDD, BDman, BDdep and SZ differed as to affected brain region(s), affected synaptic constituent(s) and extent as well as direction of dysfunction in terms of either sensitization or desensitization of transporter and/or receptor binding sites. In contrast to AD and SZ, in MDD, BDman and BDdep, neostriatal DA function was normal, whereas MDD, BDman, and BDdep were characterized by the increased availability of prefrontal and frontal DA. In contrast to AD, MDD, BDman and BDdep, DA function in SZ was impaired throughout the nigrostriatal and mesolimbocortical system with an increased availability of DA in the striatothalamocortical and a decreased availability in the mesolimbocortical pathway.
Collapse
Affiliation(s)
- Susanne Nikolaus
- Clinic of Nuclear Medicine, University Hospital Düsseldorf, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Eduards Mamlins
- Clinic of Nuclear Medicine, University Hospital Düsseldorf, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Hubertus Hautzel
- Clinic of Nuclear Medicine, University Hospital Düsseldorf, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Hans-Wilhelm Müller
- Clinic of Nuclear Medicine, University Hospital Düsseldorf, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| |
Collapse
|
14
|
Benlloch JM, González AJ, Pani R, Preziosi E, Jackson C, Murphy J, Barberá J, Correcher C, Aussenhofer S, Gareis D, Visvikis D, Bert J, Langstrom B, Farde L, Toth M, Haggkvist J, Caixeta FV, Kullander K, Somlai-Schweiger I, Schwaiger M. The MINDVIEW project: First results. Eur Psychiatry 2018; 50:21-27. [PMID: 29398564 DOI: 10.1016/j.eurpsy.2018.01.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 01/09/2018] [Accepted: 01/10/2018] [Indexed: 01/01/2023] Open
Abstract
We present the first results of the MINDVIEW project. An innovative imaging system for the human brain examination, allowing simultaneous acquisition of PET/MRI images, has been designed and constructed. It consists of a high sensitivity and high resolution PET scanner integrated in a novel, head-dedicated, radio frequency coil for a 3T MRI scanner. Preliminary measurements from the PET scanner show sensitivity 3 times higher than state-of-the-art PET systems that will allow safe repeated studies on the same patient. The achieved spatial resolution, close to 1 mm, will enable differentiation of relevant brain structures for schizophrenia. A cost-effective and simple method of radiopharmaceutical production from 11C-carbon monoxide and a mini-clean room has been demonstrated. It has been shown that 11C-raclopride has higher binding potential in a new VAAT null mutant mouse model of schizophrenia compared to wild type control animals. A significant reduction in TSPO binding has been found in gray matter in a small sample of drug-naïve, first episode psychosis patients, suggesting a reduced number or an altered function of immune cells in brain at early stage schizophrenia.
Collapse
Affiliation(s)
- José M Benlloch
- Institute for Instrumentation in Molecular Imaging (I3 M), Universidad Politécnica de Valencia - CSIC, Valencia, Spain
| | - Antonio J González
- Institute for Instrumentation in Molecular Imaging (I3 M), Universidad Politécnica de Valencia - CSIC, Valencia, Spain.
| | - Roberto Pani
- Department of Molecular Medicine, Sapienza University of Rome, Italy
| | - Enrico Preziosi
- Department of Molecular Medicine, Sapienza University of Rome, Italy
| | | | | | | | | | | | | | - Dimitris Visvikis
- INSERM, UMR1101, LaTIM, Université de Bretagne Occidentale, Brest, France
| | - Julien Bert
- INSERM, UMR1101, LaTIM, Université de Bretagne Occidentale, Brest, France
| | | | - Lars Farde
- Dept. of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden; Precision Medicine & Genomics, AstraZeneca, PET Science Center, Karolinska Institutet, Stockholm, Sweden
| | - Miklos Toth
- Dept. of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Jenny Haggkvist
- Dept. of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Fabio V Caixeta
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Klas Kullander
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | | | - Markus Schwaiger
- Technische Universität München, Dept. of Nuclear Medicine, Munich, Germany
| |
Collapse
|
15
|
Kim YK, Choi J, Park SC. A Novel Bio-Psychosocial-Behavioral Treatment Model in Schizophrenia. Int J Mol Sci 2017; 18:ijms18040734. [PMID: 28358303 PMCID: PMC5412320 DOI: 10.3390/ijms18040734] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 03/25/2017] [Accepted: 03/26/2017] [Indexed: 12/21/2022] Open
Abstract
Despite the substantial burden of illness in schizophrenia, there has been a discrepancy between the beneficial effects of an increased use of antipsychotic medications and achieving limited recovery or remission. Because the focus of the most common antipsychotic medications is on dopamine, which is associated with positive symptoms, there is an unmet need for patients with negative symptoms. Since cognitive and negative symptoms rather than positive symptoms are more closely associated with psychosocial impairments in patients with schizophrenia, the non-dopaminergic systems including glutamate and γ-aminobutyric acid (GABA) of the prefrontal cortex should be of concern as well. The balance of excitation and inhibition has been associated with epigenetic modifications and thus can be analyzed in terms of a neurodevelopmental and neural circuitry perspective. Hence, a novel bio-psychosocial-behavioral model for the treatment of schizophrenia is needed to account for the non-dopaminergic systems involved in schizophrenia, rather than dopaminergic mechanisms. This model can be understood from the viewpoint of neurodevelopment and neural circuitry and should include the staging care, personalized care, preventive care, reducing the cognitive deficits, and reducing stigma. Thomas R. Insel proposed this as a goal for schizophrenia treatment to be achieved by 2030.
Collapse
Affiliation(s)
- Yong-Ku Kim
- Department of Psychiatry, Korea University College of Medicine, Seoul 02841, Korea.
| | - Joonho Choi
- Department of Psychiatry, Hanyang University Guri Hospital, Guri 11923, Korea.
| | - Seon-Cheol Park
- Department of Psychiatry, Inje University College of Medicine and Haeundae Paik Hospital, Busan 48108, Korea.
| |
Collapse
|
16
|
Resnick SM. Positron Emission Tomography in Psychiatric Illness. CURRENT DIRECTIONS IN PSYCHOLOGICAL SCIENCE 2016. [DOI: 10.1111/1467-8721.ep10768776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Susan M. Resnick
- Research Assistant Professor of Psychology in the Department of Psychiatry at the University of Pennsylvania. Her research involves the integration of genetic and neuroimaging approaches to the study of brain-behavior associations in normal persons and individuals with neuropsychiatric illness
| |
Collapse
|
17
|
Pike VW. Considerations in the Development of Reversibly Binding PET Radioligands for Brain Imaging. Curr Med Chem 2016; 23:1818-69. [PMID: 27087244 PMCID: PMC5579844 DOI: 10.2174/0929867323666160418114826] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 04/04/2016] [Accepted: 04/15/2016] [Indexed: 12/17/2022]
Abstract
The development of reversibly binding radioligands for imaging brain proteins in vivo, such as enzymes, neurotransmitter transporters, receptors and ion channels, with positron emission tomography (PET) is keenly sought for biomedical studies of neuropsychiatric disorders and for drug discovery and development, but is recognized as being highly challenging at the medicinal chemistry level. This article aims to compile and discuss the main considerations to be taken into account by chemists embarking on programs of radioligand development for PET imaging of brain protein targets.
Collapse
Affiliation(s)
- Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Rm. B3C346A, 10 Center Drive, Bethesda, MD 20892, USA.
| |
Collapse
|
18
|
Wulff S, Pinborg LH, Svarer C, Jensen LT, Nielsen MØ, Allerup P, Bak N, Rasmussen H, Frandsen E, Rostrup E, Glenthøj BY. Striatal D(2/3) Binding Potential Values in Drug-Naïve First-Episode Schizophrenia Patients Correlate With Treatment Outcome. Schizophr Bull 2015; 41:1143-52. [PMID: 25698711 PMCID: PMC4535636 DOI: 10.1093/schbul/sbu220] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
One of best validated findings in schizophrenia research is the association between blockade of dopamine D2 receptors and the effects of antipsychotics on positive psychotic symptoms. The aim of the present study was to examine correlations between baseline striatal D(2/3) receptor binding potential (BP(p)) values and treatment outcome in a cohort of antipsychotic-naïve first-episode schizophrenia patients. Additionally, we wished to investigate associations between striatal dopamine D(2/3) receptor blockade and alterations of negative symptoms as well as functioning and subjective well-being. Twenty-eight antipsychotic-naïve schizophrenia patients and 26 controls were included in the study. Single-photon emission computed tomography (SPECT) with [(123)I]iodobenzamide ([(123)I]-IBZM) was used to examine striatal D(2/3) receptor BP(p). Patients were examined before and after 6 weeks of treatment with the D(2/3) receptor antagonist amisulpride. There was a significant negative correlation between striatal D(2/3) receptor BP(p) at baseline and improvement of positive symptoms in the total group of patients. Comparing patients responding to treatment to nonresponders further showed significantly lower baseline BP(p) in the responders. At follow-up, the patients demonstrated a negative correlation between the blockade and functioning, whereas no associations between blockade and negative symptoms or subjective well-being were observed. The results show an association between striatal BP(p) of dopamine D(2/3) receptors in antipsychotic-naïve first-episode patients with schizophrenia and treatment response. Patients with a low BP(p) have a better treatment response than patients with a high BP(p). The results further suggest that functioning may decline at high levels of dopamine receptor blockade.
Collapse
Affiliation(s)
- Sanne Wulff
- Center for Neuropsychiatric Schizophrenia Research (CNSR) and Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Psychiatric Center Glostrup, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences University of Copenhagen, Denmark;
| | - Lars Hageman Pinborg
- Neurobiology Research Unit (NRU), Rigshospitalet, University of Copenhagen, Denmark
| | - Claus Svarer
- Neurobiology Research Unit (NRU), Rigshospitalet, University of Copenhagen, Denmark
| | - Lars Thorbjørn Jensen
- Department of Clinical Physiology and Nuclear Medicine, Herlev Hospital, University of Copenhagen, Denmark
| | - Mette Ødegaard Nielsen
- Center for Neuropsychiatric Schizophrenia Research (CNSR) and,Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Psychiatric Center Glostrup, University of Copenhagen, Copenhagen, Denmark
| | - Peter Allerup
- Department of Education, Centre for Research in Compulsory Schooling, Aarhus University, Denmark
| | - Nikolaj Bak
- Center for Neuropsychiatric Schizophrenia Research (CNSR) and,Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Psychiatric Center Glostrup, University of Copenhagen, Copenhagen, Denmark
| | - Hans Rasmussen
- Center for Neuropsychiatric Schizophrenia Research (CNSR) and,Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Psychiatric Center Glostrup, University of Copenhagen, Copenhagen, Denmark
| | - Erik Frandsen
- Department of Diagnostics, Functional Imaging Unit and Section of Clinical Physiology and Nuclear Medicine, Glostrup Hospital, University of Copenhagen, Denmark
| | - Egill Rostrup
- Department of Diagnostics, Functional Imaging Unit and Section of Clinical Physiology and Nuclear Medicine, Glostrup Hospital, University of Copenhagen, Denmark
| | - Birte Yding Glenthøj
- Center for Neuropsychiatric Schizophrenia Research (CNSR) and,Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Psychiatric Center Glostrup, University of Copenhagen, Copenhagen, Denmark;,Department of Clinical Medicine, Faculty of Health and Medical Sciences University of Copenhagen, Denmark
| |
Collapse
|
19
|
Mueller S, Wang D, Pan R, Holt DJ, Liu H. Abnormalities in hemispheric specialization of caudate nucleus connectivity in schizophrenia. JAMA Psychiatry 2015; 72:552-60. [PMID: 25830688 PMCID: PMC4630217 DOI: 10.1001/jamapsychiatry.2014.3176] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
IMPORTANCE Hemispheric specialization of the human brain is a marker of successful neurodevelopment. Altered brain asymmetry that has been repeatedly reported in schizophrenia may represent consequences of disrupted neurodevelopment in the disorder. However, a complete picture of functional specialization in the schizophrenic brain and its connectional substrates is yet to be unveiled. OBJECTIVES To quantify intrinsic hemispheric specialization at cortical and subcortical levels and to reveal potential disease effects in schizophrenia. DESIGN, SETTING, AND PARTICIPANTS Resting-state functional connectivity magnetic resonance imaging has been previously used to quantitatively measure hemispheric specialization in healthy individuals in a reliable manner. We quantified the intrinsic hemispheric specialization at the whole brain level in 31 patients with schizophrenia and 37 demographically matched healthy controls from November 28, 2007, through June 29, 2010, using resting-state functional magnetic resonance imaging. RESULTS The caudate nucleus and cortical regions with connections to the caudate nucleus had markedly abnormal hemispheric specialization in schizophrenia. Compared with healthy controls, patients exhibited weaker specialization in the left, but the opposite pattern in the right, caudate nucleus (P < .001). Patients with schizophrenia also had a disruption of the interhemispheric coordination among the cortical regions with connections to the caudate nucleus. A linear classifier based on the specialization of the caudate nucleus distinguished patients from controls with a classification accuracy of 74% (with a sensitivity of 68% and a specificity of 78%). CONCLUSIONS AND RELEVANCE These data suggest that hemispheric specialization could serve as a potential imaging biomarker of schizophrenia that, compared with task-based functional magnetic resonance imaging measures, is less prone to the confounding effects of variation in task compliance, cognitive ability, and command of language.
Collapse
Affiliation(s)
- Sophia Mueller
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, MGH, Charlestown, MA
- Ludwig Maximilians University Munich, Institute of Clinical Radiology, Munich, Germany
| | - Danhong Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, MGH, Charlestown, MA
| | - Ruiqi Pan
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, MGH, Charlestown, MA
| | - Daphne J. Holt
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, MGH, Charlestown, MA
- Department of Psychiatry, Massachusetts General Hospital, Boston, MA
| | - Hesheng Liu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, MGH, Charlestown, MA
| |
Collapse
|
20
|
Lu FM, Yuan Z. PET/SPECT molecular imaging in clinical neuroscience: recent advances in the investigation of CNS diseases. Quant Imaging Med Surg 2015; 5:433-47. [PMID: 26029646 PMCID: PMC4426104 DOI: 10.3978/j.issn.2223-4292.2015.03.16] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 03/23/2015] [Indexed: 01/10/2023]
Abstract
Molecular imaging is an attractive technology widely used in clinical practice that greatly enhances our understanding of the pathophysiology and treatment in central nervous system (CNS) diseases. It is a novel multidisciplinary technique that can be defined as real-time visualization, in vivo characterization and qualification of biological processes at the molecular and cellular level. It involves the imaging modalities and the corresponding imaging agents. Nowadays, molecular imaging in neuroscience has provided tremendous insights into disturbed human brain function. Among all of the molecular imaging modalities, positron emission tomography (PET) and single photon emission computed tomography (SPECT) have occupied a particular position that visualize and measure the physiological processes using high-affinity and high-specificity molecular radioactive tracers as imaging probes in intact living brain. In this review, we will put emphasis on the PET/SPECT applications in Alzheimer's disease (AD) and Parkinson's disease (PD) as major CNS disorders. We will first give an overview of the main classical molecular neuroimaging modalities. Then, the major clinical applications of PET and SPECT along with molecular probes in the fields of psychiatry and neurology will be discussed.
Collapse
Affiliation(s)
- Feng-Mei Lu
- Bioimaging Core, Faculty of Health Sciences, University of Macau, Taipa, Macau SAR, China
| | - Zhen Yuan
- Bioimaging Core, Faculty of Health Sciences, University of Macau, Taipa, Macau SAR, China
| |
Collapse
|
21
|
Salavati B, Rajji TK, Price R, Sun Y, Graff-Guerrero A, Daskalakis ZJ. Imaging-based neurochemistry in schizophrenia: a systematic review and implications for dysfunctional long-term potentiation. Schizophr Bull 2015; 41:44-56. [PMID: 25249654 PMCID: PMC4266301 DOI: 10.1093/schbul/sbu132] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cognitive deficits are commonly observed in patients with schizophrenia. Converging lines of evidence suggest that these deficits are associated with impaired long-term potentiation (LTP). In our systematic review, this hypothesis is evaluated using neuroimaging literature focused on proton magnetic resonance spectroscopy, positron emission tomography, and single-photon emission computed tomography. The review provides evidence for abnormal dopaminergic, GABAergic, and glutamatergic neurotransmission in antipsychotic-naive/free patients with schizophrenia compared with healthy controls. The review concludes with a model illustrating how these abnormalities could lead to impaired LTP in patients with schizophrenia and consequently cognitive deficits.
Collapse
Affiliation(s)
- Bahar Salavati
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada;,Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Tarek K. Rajji
- *To whom correspondence should be addressed; 80 Workman Way, Room 6312, Toronto, Ontario M6J 1H4, Canada; tel: +1 416 535 8501 x 33661; fax: +1 416 583 1307; e-mail:
| | - Rae Price
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada;,Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Yinming Sun
- Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Ariel Graff-Guerrero
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Zafiris J. Daskalakis
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada;,Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, Ontario, Canada;,Department of Psychiatry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada;,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| |
Collapse
|
22
|
Striatal dopamine receptor plasticity in neurotensin deficient mice. Behav Brain Res 2014; 280:160-71. [PMID: 25449842 DOI: 10.1016/j.bbr.2014.11.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 11/04/2014] [Accepted: 11/07/2014] [Indexed: 11/21/2022]
Abstract
Schizophrenia is thought to be caused, at least in part, by dysfunction in striatal dopamine neurotransmission. Both clinical studies and animal research have implicated the dopamine neuromodulator neurotensin (NT) in the pathophysiology of schizophrenia. Utilizing male mice lacking the NT gene (NT(-/-)), these studies examined the consequences of NT deficiency on dopaminergic tone and function, investigating (1) dopamine concentrations and dopamine receptor and transporter expression and binding in dopaminergic terminal regions, and (2) the behavioral effects of selective dopamine receptor agonists on locomotion and sensorimotor gating in adult NT(-/-) mice compared to wildtype (NT(+/+)) mice. NT(-/-) mice did not differ from NT(+/+) mice in concentrations of dopamine or its metabolite DOPAC in any brain region examined. However, NT(-/-) mice showed significantly increased D1 receptor, D2 receptor, and dopamine transporter (DAT) mRNA in the caudate putamen compared to NT(+/+) controls. NT(-/-) mice also showed elevated D2 receptor binding densities in both the caudate putamen and nucleus accumbens shell compared to NT(+/+) mice. In addition, some of the behavioral effects of the D1-type receptor agonist SKF-82958 and the D2-type receptor agonist quinpirole on locomotion, startle amplitude, and prepulse inhibition were dose-dependently altered in NT(-/-) mice, showing altered D1-type and D2-type receptor sensitivity to stimulation by agonists in the absence of NT. The results indicate that NT deficiency alters striatal dopamine receptor expression, binding, and function. This suggests a critical role for the NT system in the maintenance of striatal DA system homeostasis and implicates NT deficiency in the etiology of dopamine-associated disorders such as schizophrenia.
Collapse
|
23
|
Liu A, Chen X, Wang ZJ, Xu Q, Appel-Cresswell S, McKeown MJ. A genetically informed, group FMRI connectivity modeling approach: application to schizophrenia. IEEE Trans Biomed Eng 2014; 61:946-56. [PMID: 24557696 DOI: 10.1109/tbme.2013.2294151] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
While neuroimaging data can provide valuable phenotypic information to inform genetic studies, the opposite is also true: known genotypes can be used to inform brain connectivity patterns from fMRI data. Here, we propose a framework for genetically informed group brain connectivity modeling. Subjects are first stratified according to their genotypes, and then a group regularized regression model is employed for brain connectivity modeling utilizing the time courses from a priori specified regions of interest (ROIs). With such an approach, each ROI time course is in turn predicted from all other ROI time courses at zero lag using a group regression framework which also incorporates a penalty based on genotypic similarity. Simulations supported such an approach when, as previously studies have indicated to be the case, genetic influences impart connectivity differences across subjects. The proposed method was applied to resting state fMRI data from Schizophrenia and normal control subjects. Genotypes were based on D-amino acid oxidase activator (DAOA) single-nucleotide polymorphisms (SNPs) information. With DAOA SNPs information integrated, the proposed approach was able to more accurately model the diversity in connectivity patterns. Specifically, connectivity with the left putamen, right posterior cingulate, and left middle frontal gyri were found to be jointly modulated by DAOA genotypes and the presence of Schizophrenia. We conclude that the proposed framework represents a multimodal analysis approach for incorporating genotypic variability into brain connectivity analysis directly.
Collapse
|
24
|
Kim E, Howes OD, Kapur S. Molecular imaging as a guide for the treatment of central nervous system disorders. DIALOGUES IN CLINICAL NEUROSCIENCE 2014. [PMID: 24174903 PMCID: PMC3811103 DOI: 10.31887/dcns.2013.15.3/ekim] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Molecular imaging techniques have a number of advantages for research into the pathophysiology and treatment of central nervous system (CNS) disorders. Firstly, they provide a noninvasive means of characterizing physiological processes in the living brain, enabling molecular alterations to be linked to clinical changes. Secondly, the pathophysiological target in a given CNS disorder can be measured in animal models and in experimental human models in the same way, which enables translational research. Moreover, as molecular imaging facilitates the detection of functional change which precedes gross pathology, it is particularly useful for the early diagnosis and treatment of CNS disorders. This review considers the application of molecular imaging to CNS disorders focusing on its potential to inform the development and evaluation of treatments. We focus on schizophrenia, Parkinson's disease, depression, and dementia as major CNS disorders. We also review the potential of molecular imaging to guide new drug development for CNS disorders.
Collapse
Affiliation(s)
- Euitae Kim
- Department of Neuropsychiatry, Seoul National University Bundang Hospital, Gyeonggi-do 463-707, Korea
| | | | | |
Collapse
|
25
|
Nikolaus S, Hautzel H, Müller HW. Neurochemical dysfunction in treated and nontreated schizophrenia - a retrospective analysis of in vivo imaging studies. Rev Neurosci 2014; 25:25-96. [PMID: 24486731 DOI: 10.1515/revneuro-2013-0063] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 12/26/2013] [Indexed: 12/22/2022]
Abstract
To evaluate the contribution of individual synaptic constituents, all available in vivo imaging studies on schizophrenic patients were subjected to a retrospective analysis. For the pool of drug-naïve, drug-free, and acutely medicated patients, major findings were increases in neostriatal dopamine (DA) synthesis and release and decreases in neostriatal DA transporters and D1 receptors, neostriatal, thalamic, frontal, and parietal D2 receptors, mesencephalic/pontine and temporal 5-HT1A receptors, frontal and temporal HT2A and μ-amino butyric acid (GABA)A receptors. Based on the findings on drug-naïve and drug-free patients, it may be hypothesized that schizophrenia initially is characterized by an impaired mechanism of D2 autoreceptor and heteroreceptor sensitization leading to sensitization instead of desensitization in response to increased levels of neostriatal DA. Neuroleptic medication blocks neostriatal D2 autoreceptor and heteroreceptors, reducing neostriatal DA and disinhibiting DA action mediated by D2 heteroreceptor binding sites. Ultimately, this may result in a restitution of GABA function, leading to a recovery of inhibitory input to the target regions of the descending corticothalamostriatal efferents. Furthermore, a blockade of inhibitory and excitatory neocortical 5-HT function may be inferred, which is likely to reduce (excitatory) DAergic input to the mesolimbic target regions of corticothalamostriatal projections.
Collapse
|
26
|
Seeman MV, Seeman P. Is schizophrenia a dopamine supersensitivity psychotic reaction? Prog Neuropsychopharmacol Biol Psychiatry 2014; 48:155-60. [PMID: 24128684 PMCID: PMC3858317 DOI: 10.1016/j.pnpbp.2013.10.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 10/03/2013] [Accepted: 10/03/2013] [Indexed: 12/22/2022]
Abstract
Adolf Meyer (1866-1950) did not see schizophrenia as a discrete disorder with a specific etiology but, rather, as a reaction to a wide variety of biopsychosocial factors. He may have been right. Today, we have evidence that gene mutations, brain injury, drug use (cocaine, amphetamine, marijuana, phencyclidine, and steroids), prenatal infection and malnutrition, social isolation and marginalization, can all result in the signs and symptoms of schizophrenia. This clinical picture is generally associated with supersensitivity to dopamine, and activates dopamine neurotransmission that is usually alleviated or blocked by drugs that block dopamine D2 receptors. While the dopamine neural pathway may be a final common route to many of the clinical symptoms, the components of this pathway, such as dopamine release and number of D2 receptors, are approximately normal in schizophrenia patients who are in remission. Postmortem findings, however, reveal more dimers of D1D2 and D2D2 receptors in both human schizophrenia brains and in animal models of schizophrenia. Another finding in animal models is an elevation of high-affinity state D2High receptors, but no radioactive ligand is yet available to selectively label D2High receptors in humans. It is suggested that synaptic dopamine supersensitivity in schizophrenia is an attempt at compensation for the original damage by heightening dopamine neurotransmission pathways (preparing the organism for fight or flight). The dopamine overactivity is experienced subjectively as overstimulation, which accounts for some of the clinical symptoms, with attempts at dampening down the stimulation leading to still other symptoms. Reaction and counter-reaction may explain the symptoms of schizophrenia.
Collapse
Affiliation(s)
- Mary V. Seeman
- Departments of Psychiatry, University of Toronto, 260 Heath St. West, Suite 605, Toronto, Ontario M5P 3L6, Canada
| | - Philip Seeman
- Departments of Pharmacology, University of Toronto, 260 Heath St. West, Suite 605, Toronto, Ontario M5P 3L6, Canada,Corresponding author. Tel.: +1 416 486 3456. (P. Seeman)
| |
Collapse
|
27
|
Seeman P. Schizophrenia thalamus imaging: low benzamide binding to dopamine D2 receptors suggests fewer D2Short receptors and fewer presynaptic terminals. Psychiatry Res 2013; 214:175-80. [PMID: 24120301 DOI: 10.1016/j.pscychresns.2013.09.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 09/07/2013] [Accepted: 09/20/2013] [Indexed: 01/08/2023]
Abstract
The dopamine D2 receptor continues to be the major target for the treatment of schizophrenia and is one of many genes genetically associated with this disease. Recent data show that fewer short forms of the D2 receptor protein are synthesized if there is a genetic variant in the D2 receptor (with a T in rs 1076560 in intron 6). At the same time, at least six publications report that the binding of radioactive benzamides is reduced in the schizophrenia thalamus. A review of the benzamide pharmacology of the short and long forms of the D2 receptor shows that benzamides have a 2.4-fold higher affinity for the D2Short receptor relative to the D2Long form. Hence, the reduced amount of benzamide binding to the D2 receptors in the schizophrenia thalamus suggests that there is a reduced amount of D2Short receptors in this diseased region, and may possibly also mean fewer presynaptic terminals because that is where D2Short receptors mostly reside. If so, fewer presynaptic dopamine terminals in various brain regions may be the basis of the known behavioural dopamine supersensitivity in schizophrenia.
Collapse
Affiliation(s)
- Philip Seeman
- Departments of Pharmacology and Psychiatry, University of Toronto, 260 Heath Street West, Unit 605, Toronto, Ont., Canada M5P 3L6.
| |
Collapse
|
28
|
Seeman P. Are dopamine D2 receptors out of control in psychosis? Prog Neuropsychopharmacol Biol Psychiatry 2013; 46:146-52. [PMID: 23880595 DOI: 10.1016/j.pnpbp.2013.07.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 07/08/2013] [Accepted: 07/08/2013] [Indexed: 01/11/2023]
Abstract
It is known that schizophrenia patients are behaviorally supersensitive to dopamine-like drugs (amphetamine, methylphenidate). There is evidence for an increased release of dopamine, a slight increase of dopamine D2 receptors and an increase of dopamine D2High receptors in schizophrenia, all possibly explaining the clinical supersensitivity to dopamine. The elevation in apparent D2High receptors in vivo in schizophrenia matches the elevation in D2High receptors in many animal models of psychosis. The increased amounts of D2High receptors in psychotic-like behavior in animals may result from a loss of control of D2 by various factors. These factors include the rate of phosphorylation and desensitization of D2 receptors by kinases, the attachment of arrestin to D2 receptors, internalization of D2 receptors, the rate of receptor de-phosphorylation, formation of D2 receptor dimers, and GTP regulation by various GTPases. While at present there are no statistically significant associations of any of these controlling factors and their genes with schizophrenia, investigation of D2High receptors in schizophrenia will require a new radioligand in order to selectively label D2High receptors in vivo in patients. Finally, haloperidol reduces the number of D2High receptors that are elevated by amphetamine, indicating that this therapeutic effect may occur clinically.
Collapse
Affiliation(s)
- Philip Seeman
- Department of Pharmacology, University of Toronto, 260 Heath Street, West, unit 605, Toronto, Ontario M5P 3L6, Canada; Department of Psychiatry, University of Toronto, 260 Heath Street, West, unit 605, Toronto, Ontario, M5P 3L6, Canada.
| |
Collapse
|
29
|
Seeman P. Schizophrenia and dopamine receptors. Eur Neuropsychopharmacol 2013; 23:999-1009. [PMID: 23860356 DOI: 10.1016/j.euroneuro.2013.06.005] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 04/06/2013] [Accepted: 06/24/2013] [Indexed: 02/06/2023]
Abstract
Schizophrenia patients are behaviorally supersensitive to dopamine-like drugs such as amphetamine or methylphenidate, meaning that patients respond to such drugs with increased psychotic symptoms, as compared to control subjects. A basis of such supersensitivity may be an increased pre-synaptic release of dopamine or a post-synaptic elevation of D2 receptors or of D2High receptors in active stages of schizophrenia. While the pre-synaptic release of dopamine is normal in stable patients with schizophrenia, brain imaging studies find that D2 receptors are increased by an average of 5.8% in antipsychotic-free schizophrenia patients. It is possible that the behavioral supersensitivity may stem from more D2High receptors in schizophrenia. Although the antipsychotic/dopamine D2 receptor can exist in vitro in a state of high affinity for dopamine (as D2High), or in a state of low affinity for dopamine (as D2Low), there is no clear evidence that D2High states can be selectively labeled or stably exist in vivo. Nevertheless, two studies revealed an 80% increase in apparent D2High receptors in schizophrenia patients after reducing endogenous dopamine. The elevation in apparent D2High receptors in vivo in schizophrenia matches the elevation in D2High receptors in vitro in animal models of psychosis, including dopamine-supersensitive animals pretreated with amphetamine, marijuana, or phencyclidine, or animals with gene knockouts in various neurotransmitter pathways, including those for glutamate receptors. The elevation of D2High receptors in vitro and the increased apparent D2High receptors in vivo is consistent with behavioral dopamine supersensitivity in schizophrenia patients.
Collapse
Affiliation(s)
- Philip Seeman
- Department of Psychiatry, University of Toronto, 260 Heath Street, West, Unit 605, Toronto, Ont., Canada M5P 3L6; Department of Pharmacology, University of Toronto, 260 Heath Street, West, Unit 605, Toronto, Ont., Canada M5P 3L6.
| |
Collapse
|
30
|
Modeling of PET data in CNS drug discovery and development. J Pharmacokinet Pharmacodyn 2013; 40:267-79. [PMID: 23660778 DOI: 10.1007/s10928-013-9320-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 04/26/2013] [Indexed: 12/22/2022]
Abstract
Positron emission tomography (PET) is increasingly used in drug discovery and development for evaluation of CNS drug disposition and for studies of disease biomarkers to monitor drug effects on brain pathology. The quantitative analysis of PET data is based on kinetic modeling of radioactivity concentrations in plasma and brain tissue compartments. A number of quantitative methods of analysis have been developed that allow the determination of parameters describing drug pharmacokinetics and interaction with target binding sites in the brain. The optimal method of quantification depends on the properties of the radiolabeled drug or radioligand and the binding site studied. We here review the most frequently used methods for quantification of PET data in relation to CNS drug discovery and development. The utility of PET kinetic modeling in the development of novel CNS drugs is illustrated by examples from studies of the brain kinetic properties of radiolabeled drug molecules.
Collapse
|
31
|
Striatal and extrastriatal dopamine D2 receptor occupancy by a novel antipsychotic, blonanserin: a PET study with [11C]raclopride and [11C]FLB 457 in schizophrenia. J Clin Psychopharmacol 2013; 33:162-9. [PMID: 23422369 DOI: 10.1097/jcp.0b013e3182825bce] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Blonanserin is a novel antipsychotic with high affinities for dopamine D(2) and 5-HT(2A) receptors, and it was recently approved for the treatment of schizophrenia in Japan and Korea. Although double-blind clinical trials have demonstrated that blonanserin has equal efficacy to risperidone, and with a better profile especially with respect to prolactin elevation, its profile of in vivo receptor binding has not been investigated in patients with schizophrenia. Using positron emission tomography (PET), we measured striatal and extrastriatal dopamine D(2) receptor occupancy by blonanserin in 15 patients with schizophrenia treated with fixed doses of blonanserin (ie, 8, 16, and 24 mg/d) for at least 4 weeks before PET scans, and in 15 healthy volunteers. Two PET scans, 1 with [(11)C]raclopride for the striatum and 1 with [(11)C]FLB 457 for the temporal cortex and pituitary, were performed on the same day. Striatal dopamine D(2) receptor occupancy by blonanserin was 60.8% (3.0%) [mean (SD)] at 8 mg, 73.4% (4.9%) at 16 mg, and 79.7% (2.3%) at 24 mg. The brain/plasma concentration ratio calculated from D(2) receptor occupancy in the temporal cortex and pituitary was 3.38, indicating good blood-brain barrier permeability. This was the first study to show clinical daily dose amounts of blonanserin occupying dopamine D(2) receptors in patients with schizophrenia. The clinical implications obtained in this study were the optimal therapeutic dose range of 12.9 to 22.1 mg/d of blonanserin required for 70% to 80% dopamine D(2) receptor occupancy in the striatum, and the good blood-brain barrier permeability that suggested a relatively lower risk of hyperprolactinemia.
Collapse
|
32
|
Suridjan I, Rusjan P, Addington J, Wilson AA, Houle S, Mizrahi R. Dopamine D2 and D3 binding in people at clinical high risk for schizophrenia, antipsychotic-naive patients and healthy controls while performing a cognitive task. J Psychiatry Neurosci 2013; 38:98-106. [PMID: 23010256 PMCID: PMC3581597 DOI: 10.1503/jpn.110181] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND The dopamine (DA) D2 receptors exist in 2 states: a high-affinity state (D2 high) that is linked to second messenger systems, responsible for functional effects, exhibits high affinity for agonists (e.g., DA), and a low-affinity state that is functionally inert exhibits lower affinity for agonists. The DA D3 receptor subtype exhibits high agonist affinity, whereas the existence of the multiple affinity states is controversial. Preclinical studies in animal models of psychosis have shown a selective increase of D2 high as the common factor in psychosis, and the D3 receptor has been suggested to be involved in the pathophysiology of schizophrenia. METHODS We studied D2 high and D3 in people at clinical high risk (CHR) for schizophrenia and in antipsychotic-naive patients with schizophrenia using the novel positron emission tomography radiotracer, [11C]-(+)-PHNO. The binding potential nondisplaceable (BP(ND)) was examined in the regions of interest (ROI; caudate, putamen, ventral striatum, globus pallidus, substantia nigra and thalamus) using an ROI and a voxel-wise approach while participants performed a cognitive task. RESULTS We recruited 12 CHR individuals and 13 antipsychotic-naive patients with schizophrenia-spectrum disorder, whom we compared with 12 age- and sex-matched healthy controls. The BP(ND) between patients and controls did not differ in any of the ROIs, consistent with the voxel-wise analysis. Correlations between the BP(ND) in D3-rich regions and psychopathology warrant further investigation. LIMITATIONS In the absence of resting-state (baseline) BP(ND) data, or following a depletion paradigm (i.e., α-methyl partyrosine), it is not possible to ascertain whether the lack of difference among the groups is owing to different levels of baseline DA or to release during the cognitive task. CONCLUSION To our knowledge, the present study represents the first effort to measure the D2 and D3 receptors under a cognitive challenge in individuals putative/prodromal for schizophrenia using [11C]-(+)-PHNO.
Collapse
Affiliation(s)
| | | | | | | | | | - Romina Mizrahi
- Correspondence to: R. Mizrahi, PET Centre, Centre for Addiction and Mental Health, 250 College St., Toronto ON M5T 1R8;
| |
Collapse
|
33
|
Martín A, Gómez-Vallejo V, San Sebastián E, Padró D, Markuerkiaga I, Llarena I, Llop J. In vivo imaging of dopaminergic neurotransmission after transient focal ischemia in rats. J Cereb Blood Flow Metab 2013; 33:244-52. [PMID: 23149560 PMCID: PMC3564194 DOI: 10.1038/jcbfm.2012.162] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The precise biologic mechanisms involved in functional recovery processes in response to stroke such as dopaminergic neurotransmission are still largely unknown. For this purpose, we performed in parallel in vivo magnetic resonance imaging and positron emission tomography (PET) with [(18)F]fluorodeoxyglucose ([(18)F]FDG) and [(11)C]raclopride at 1, 3, 7, 14, 21, and 28 days after middle cerebral artery occlusion in rats. In the ischemic territory, PET [(18)F]FDG showed a initial decrease in cerebral metabolism followed by a time-dependent recovery to quasi-normal values at day 14 after ischemia. The PET with [(11)C]raclopride, a ligand for dopamine D(2) receptor, showed a sustained binding during the first week after ischemia that declined dramatically from day 14 to day 28. Interestingly, a slight increase in [(11)C]raclopride binding was observed at days 1 to 3 followed by the uppermost binding at day 7 in the contralateral territory. Likewise, in vitro autoradiography using [(3)H]raclopride confirmed these in vivo results. Finally, the neurologic test showed major neurologic impairment at day 1 followed by a recovery of the cerebral function at day 28 after cerebral ischemia. Taken together, these results might suggest that dopamine D(2) receptor changes in the contralateral hemisphere could have a key role in functional recovery after cerebral ischemia.
Collapse
Affiliation(s)
- Abraham Martín
- Molecular Imaging Unit, CIC biomaGUNE, San Sebastián, Spain.
| | | | | | | | | | | | | |
Collapse
|
34
|
Howes OD, Kambeitz J, Kim E, Stahl D, Slifstein M, Abi-Dargham A, Kapur S. The nature of dopamine dysfunction in schizophrenia and what this means for treatment. ACTA ACUST UNITED AC 2012; 69:776-86. [PMID: 22474070 DOI: 10.1001/archgenpsychiatry.2012.169] [Citation(s) in RCA: 645] [Impact Index Per Article: 53.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
CONTEXT Current drug treatments for schizophrenia are inadequate for many patients, and despite 5 decades of drug discovery, all of the treatments rely on the same mechanism: dopamine D(2) receptor blockade. Understanding the pathophysiology of the disorder is thus likely to be critical to the rational development of new treatments for schizophrenia. OBJECTIVE To investigate the nature of the dopaminergic dysfunction in schizophrenia using meta-analysis of in vivo studies. DATA SOURCES The MEDLINE, EMBASE, and PsycINFO databases were searched for studies from January 1, 1960, to July 1, 2011. STUDY SELECTION A total of 44 studies were identified that compared 618 patients with schizophrenia with 606 controls, using positron emission tomography or single-photon emission computed tomography to measure in vivo striatal dopaminergic function. DATA EXTRACTION Demographic, clinical, and imaging variables were extracted from each study, and effect sizes were determined for the measures of dopaminergic function. Studies were grouped into those of presynaptic function and those of dopamine transporter and receptor availability. Sensitivity analyses were conducted to explore the consistency of effects and the effect of clinical and imaging variables. DATA SYNTHESIS There was a highly significant elevation (P.<001) in presynaptic dopaminergic function in schizophrenia with a large effect size (Cohen d=0.79). There was no evidence of alterations in dopamine transporter availability. There was a small elevation in D(2/3) receptor availability (Cohen d=0.26), but this was not evident in drug-naive patients and was influenced by the imaging approach used. CONCLUSIONS The locus of the largest dopaminergic abnormality in schizophrenia is presynaptic, which affects dopamine synthesis capacity, baseline synaptic dopamine levels, and dopamine release. Current drug treatments, which primarily act at D(2/3) receptors, fail to target these abnormalities. Future drug development should focus on the control of presynaptic dopamine synthesis and release capacity.
Collapse
Affiliation(s)
- Oliver D Howes
- Department of Psychosis Studies, Institute of Psychiatry, King's College London, Camberwell, UK.
| | | | | | | | | | | | | |
Collapse
|
35
|
Striatal and extrastriatal dopamine D₂ receptor occupancy by the partial agonist antipsychotic drug aripiprazole in the human brain: a positron emission tomography study with [¹¹C]raclopride and [¹¹C]FLB457. Psychopharmacology (Berl) 2012; 222:165-72. [PMID: 22237854 DOI: 10.1007/s00213-011-2633-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2011] [Accepted: 12/26/2011] [Indexed: 10/14/2022]
Abstract
RATIONALE Second-generation antipsychotics demonstrate clinical efficacy with fewer extrapyramidal side effects compared with first-generation antipsychotics. One of the proposed explanations is the hypothesis of preferential extrastriatal dopamine D₂ receptor occupancy (limbic selectivity) by antipsychotics. In the present study, we focused on aripiprazole, which has a unique pharmacological profile with partial agonism at dopamine D₂ receptors and the minimal risk of extrapyramidal side effects. Previous positron emission tomography (PET) studies using high-affinity radioligands for dopamine D₂ receptors have reported inconsistent results regarding regional differences of dopamine D₂ receptor occupancy by aripiprazole. OBJECTIVE To test the hypothesis of preferential binding to extrastriatal dopamine D₂ receptors by aripiprazole, we investigated its regional dopamine D₂ receptor occupancies in healthy young subjects. MATERIALS AND METHODS Using PET and two radioligands with different affinities for dopamine D₂ receptors, [¹¹C]raclopride and [¹¹C]FLB457, striatal and extrastriatal dopamine D₂ receptor bindings at baseline and after oral administration of 6 mg aripiprazole were measured in 11 male healthy subjects. RESULTS Our data showed that dopamine D₂ receptor occupancies in the striatum measured with [¹¹C]raclopride were 70.1% and 74.1%, with the corresponding values for the extrastriatal regions measured with [¹¹C]FLB457 ranging from 46.6% to 58.4%. CONCLUSIONS In the present study, preferential extrastriatal dopamine D₂ receptor occupancy by aripiprazole was not observed. Our data suggest partial agonism at dopamine D₂ receptors is the most likely explanation for the minimal risk of extrapyramidal side effects in the treatment by aripiprazole.
Collapse
|
36
|
Spiros A, Roberts P, Geerts H. A Quantitative Systems Pharmacology Computer Model for Schizophrenia Efficacy and Extrapyramidal Side Effects. Drug Dev Res 2012. [DOI: 10.1002/ddr.21008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
|
37
|
Kuwabara H, McCaul ME, Wand GS, Earley CJ, Allen RP, Weerts EM, Dannals RF, Wong DF. Dissociative changes in the Bmax and KD of dopamine D2/D3 receptors with aging observed in functional subdivisions of the striatum: a revisit with an improved data analysis method. J Nucl Med 2012; 53:805-12. [PMID: 22492734 DOI: 10.2967/jnumed.111.098186] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Separate measurements of B(max), the density of available receptors, and K(D), the equilibrium dissociation constant in the human brain, with PET have contributed to our understanding of neuropsychiatric disorders, especially with respect to the dopamine D(2)/D(3) receptor system. However, existing methods have limited applications to the whole striatum, putamen, or caudate nucleus. Improved methods are required to examine B(max) and K(D) in detailed functional striatal subdivisions that are becoming widely used. METHODS In response, a new method (bolus-plus-infusion transformation [BPIT]) was developed. After completion of a validation study for (11)C-raclopride scans involving 81 subjects, age-associated changes in B(max) and K(D) were examined in 47 healthy subjects ranging in age from 18 to 77 y. RESULTS The BPIT method was consistent with established reference tissue methods regarding regional binding potential. BPIT yielded time-consistent estimates of B(max) and K(D) when scan and infusion lengths were set equal in the analysis. In addition, BPIT was shown to be robust against PET measurement errors when compared with a widely accepted transient equilibrium method. Altogether, BPIT was supported as a method for regional binding potential, B(max), and K(D). We demonstrated age-associated declines in B(max) in all 5 functional striatal subdivisions with BPIT when corrected for multiple comparisons. These age-related effects were not consistently attainable with the transient equilibrium method. Irrespective to methods, K(D) remained unchanged with age. CONCLUSION The BPIT approach may be useful for understanding dopamine receptor abnormalities in neuropsychiatric disorders by enabling separate measurements of B(max) and K(D) in functional striatal subdivisions.
Collapse
Affiliation(s)
- Hiroto Kuwabara
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Vauquelin G, Bostoen S, Vanderheyden P, Seeman P. Clozapine, atypical antipsychotics, and the benefits of fast-off D2 dopamine receptor antagonism. Naunyn Schmiedebergs Arch Pharmacol 2012; 385:337-72. [PMID: 22331262 DOI: 10.1007/s00210-012-0734-2] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 01/25/2012] [Indexed: 12/20/2022]
Abstract
Drug-receptor interactions are traditionally quantified in terms of affinity and efficacy, but there is increasing awareness that the drug-on-receptor residence time also affects clinical performance. While most interest has hitherto been focused on slow-dissociating drugs, D(2) dopamine receptor antagonists show less extrapyramidal side effects but still have excellent antipsychotic activity when they dissociate swiftly. Fast dissociation of clozapine, the prototype of the "atypical antipsychotics", has been evidenced by distinct radioligand binding approaches both on cell membranes and intact cells. The surmountable nature of clozapine in functional assays with fast-emerging responses like calcium transients is confirmatory. Potential advantages and pitfalls of the hitherto used techniques are discussed, and recommendations are given to obtain more precise dissociation rates for such drugs. Surmountable antagonism is necessary to allow sufficient D(2) receptor stimulation by endogenous dopamine in the striatum. Simulations are presented to find out whether this can be achieved during sub-second bursts in dopamine concentration or rather during much slower, activity-related increases thereof. While the antagonist's dissociation rate is important to distinguish between both mechanisms, this becomes much less so when contemplating time intervals between successive drug intakes, i.e., when pharmacokinetic considerations prevail. Attention is also drawn to the divergent residence times of hydrophobic antagonists like haloperidol when comparing radioligand binding data on cell membranes with those on intact cells and clinical data.
Collapse
Affiliation(s)
- Georges Vauquelin
- Department of Molecular and Biochemical Pharmacology, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium.
| | | | | | | |
Collapse
|
39
|
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.
Collapse
|
40
|
Relation between presynaptic and postsynaptic dopaminergic functions measured by positron emission tomography: implication of dopaminergic tone. J Neurosci 2011; 31:7886-90. [PMID: 21613502 DOI: 10.1523/jneurosci.6024-10.2011] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Both presynaptic and postsynaptic dopaminergic functions can be estimated by positron emission tomography (PET). While both presynaptic and postsynaptic dopaminergic functions would be regulated by corresponding genes and related to personality traits, the relation between presynaptic and postsynaptic functions in terms of interindividual variation has hardly been investigated. In the present study, both striatal dopamine D(2) receptor binding and endogenous dopamine synthesis rate were measured in the same healthy subjects using PET with [(11)C]raclopride and l-[β-(11)C]DOPA, respectively, and these two parameters were compared. Two PET studies with [(11)C]raclopride and l-[β-(11)C]DOPA were performed sequentially at rest condition on 14 healthy men. For [(11)C]raclopride PET, the binding potential was calculated by the reference tissue model method. For l-[β-(11)C]DOPA PET, the endogenous dopamine synthesis rate was estimated by graphical analysis. A significant negative correlation was observed between the binding potential of dopamine D(2) receptors and endogenous dopamine synthesis rate (r = -0.66, p < 0.05). Although the interindividual variation of binding potential of [(11)C]raclopride would be due to both the interindividual difference in the receptor density and that in the concentration of endogenous dopamine in the synaptic cleft, the negative correlation between parameters for both presynaptic and postsynaptic functions might indicate a compensative relation between the two functions.
Collapse
|
41
|
Antipsychotic-associated mental side effects and their relationship to dopamine D2 receptor occupancy in striatal subdivisions: a high-resolution PET study with [11C]raclopride. J Clin Psychopharmacol 2011; 31:507-11. [PMID: 21694619 DOI: 10.1097/jcp.0b013e318222353a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We examined the relationship between antipsychotic-associated mental side effects and dopamine D2 receptor occupancy in striatal subdivisions using high-resolution positron emission tomography with [11C]raclopride to better characterize the neurochemical mechanism underlying these adverse effects. Twenty-one patients with schizophrenia receiving stable doses of antipsychotics and 24 age- and sex-matched healthy controls completed 3-Tesla magnetic resonance imaging and high-resolution positron emission tomography scans with [11C]raclopride to measure D2 receptor binding potential (BP ND) in the striatum. The D2 receptor BP ND was obtained using a Logan plot, and receptor occupancy was calculated as the percentage reduction of receptor BP ND with drug treatment relative to baseline. The data obtained from age- and sex-matched healthy controls were used as an estimate of the patients' baseline, as previously proposed. Antipsychotic-associated mental side effects were measured with the Liverpool University Neuroleptic Side Effect Rating Scale. The whole striatal D2 receptor occupancy ranged from 54% to 95%. The analysis revealed that the Liverpool University Neuroleptic Side Effect Rating Scale score had significant positive associations with D2 occupancy in the precommissural dorsal caudate, postcommissural caudate, and ventral striatum. The results suggest that mental side effects of antipsychotics are associated with D2 receptor blockade in the associative and limbic subdivisions of the striatum, which are considered to play a crucial role in cognition and reward motivation.
Collapse
|
42
|
Kim E, Howes OD, Yu KS, Jeong JM, Lee JS, Jang IJ, Shin SG, Kapur S, Kwon JS. Calculating occupancy when one does not have baseline: a comparison of different options. J Cereb Blood Flow Metab 2011; 31:1760-7. [PMID: 21522162 PMCID: PMC3170949 DOI: 10.1038/jcbfm.2011.54] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dopamine D(2) receptor occupancy of antipsychotic drugs is calculated relative to the subject's D(2) receptor binding potential (BP) in the drug-free state (baseline BP). Because baseline BP is seldom known in patients with schizophrenia, population means from unrelated control samples are often used to estimate it. However, this is likely to introduce bias and error into the occupancy measure. There is thus a need for a method to reliably estimate baseline BP for patient populations in whom it may be impractical or unethical to get baseline measurements. It has been previously found that the relationship between plasma concentration and dopamine receptor occupancy by antipsychotic drugs follows a sigmoid E(max) model. Based on this, we developed a method for calculating dopamine D(2) receptor occupancy by antipsychotic drugs using an inhibitory E(max) model (I(max) method) that estimates individual baseline BPs. To validate this, we compared the result from the I(max) method with actual occupancy and estimated occupancy calculated from the average baseline BP (substitution method). The data for validation were obtained from two different receptor occupancy studies with the antipsychotic medications YKP1358 and aripiprazole. We estimated the reliability between the true measured occupancy and the predicted occupancy using the intraclass correlation coefficient (ICC), and the variability of occupancy was also compared between the I(max) and substitution methods. In YKP1358 study, all the ICCs of the I(max) method were above 0.8, but those of the substitution method showed values lower than 0.8. In aripiprazole study, the ICCs of the I(max) method were higher than those of the substitution method, but all the ICCs showed higher values than 0.8. The variability of I(max) method was significantly smaller than that of substitution method in both studies. The I(max) method shows better reliability and less variability than the substitution method. The I(max) method can be applied for receptor occupancy study, and bring more reliability and accuracy to the occupancy study in patients with schizophrenia.
Collapse
Affiliation(s)
- Euitae Kim
- Department of Psychiatry, Seoul National University College of Medicine, Seoul, Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Seeman P. All roads to schizophrenia lead to dopamine supersensitivity and elevated dopamine D2(high) receptors. CNS Neurosci Ther 2011; 17:118-32. [PMID: 20560996 DOI: 10.1111/j.1755-5949.2010.00162.x] [Citation(s) in RCA: 158] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The dopamine D2 receptor is the common target for antipsychotics, and the antipsychotic clinical doses correlate with their affinities for this receptor. Antipsychotics quickly enter the brain to occupy 60-80% of brain D2 receptors in patients (the agonist aripiprazole occupies up to 90%), with most clinical improvement occurring within a few days. The D2 receptor can exist in a state of high-affinity (D2(High) ) or in a state of low-affinity for dopamine (D2Low). AIM The present aim is to review why individuals with schizophrenia are generally supersensitive to dopamine-like drugs such as amphetamine or methyphenidate, and whether the D2(High) state is a common basis for dopamine supersensitivity in the animal models of schizophrenia. RESULTS All animal models of schizophrenia reveal elevations in D2(High) receptors. These models include brain lesions, sensitization by drugs (amphetamine, phencyclidine, cocaine, corticosterone), birth injury, social isolation, and gene deletions in pathways for NMDA, dopamine, GABA, acetylcholine, and norepinephrine. CONCLUSIONS These multiple abnormal pathways converge to a final common pathway of dopamine supersensitivity and elevated D2(High) receptors, presumably responsible for psychotic symptoms. Although antipsychotics alleviate psychosis and reverse the elevation of D2(High) receptors, long-term antipsychotics can further enhance dopamine supersensitivity in patients. Therefore, switching from a traditional antipsychotic to an agonist antipsychotic (aripiprazole) can result in psychotic signs and symptoms. Clozapine and quetiapine do not elicit parkinsonism or tardive dyskinesia because they are released from D2 within 12 to 24 h. Traditional antipsychotics remain attached to D2 receptors for days, preventing relapse, but allowing accumulation that can lead to tardive dyskinesia. Future goals include imaging D2(High) receptors and desensitizing them in early-stage psychosis.
Collapse
Affiliation(s)
- Philip Seeman
- Departments of Pharmacology and Psychiatry, University of Toronto, 260 Heath Street West, Suite 605, Toronto, Ontario, Canada M5P 3L6.
| |
Collapse
|
44
|
González-Maeso J. GPCR oligomers in pharmacology and signaling. Mol Brain 2011; 4:20. [PMID: 21619615 PMCID: PMC3128055 DOI: 10.1186/1756-6606-4-20] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 05/27/2011] [Indexed: 12/15/2022] Open
Abstract
G protein-coupled receptors (GPCRs) represent one of the largest families of cell surface receptors, and are the target of more than half of the current therapeutic drugs on the market. When activated by an agonist, the GPCR undergoes conformational changes that facilitate its interaction with heterotrimeric G proteins, which then relay signals to downstream intracellular effectors. Although GPCRs were thought to function as monomers, many studies support the hypothesis that G protein coupling involves the formation of GPCR homo- and/or hetero-complexes. These complex systems have been suggested to exhibit specific signaling cascades, pharmacological, internalization, and recycling properties. In this review, we summarize recent advances in our understanding of the structure, function and dynamics of GPCR complexes, as well as the findings obtained in animal models.
Collapse
Affiliation(s)
- Javier González-Maeso
- Departments of Psychiatry and Neurology, Friedman Brain Institute, Mount Sinai School of Medicine, New York, NY, USA.
| |
Collapse
|
45
|
|
46
|
|
47
|
How does the physiology change with symptom exacerbation and remission in schizophrenia? Behav Brain Sci 2011. [DOI: 10.1017/s0140525x00065122] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
48
|
|
49
|
|
50
|
|