1
|
Dadgostar E, Moghanlou M, Parvaresh M, Mohammadi S, Khandan M, Aschner M, Mirzaei H, Tamtaji OR. Can Berberine Serve as a New Therapy for Parkinson's Disease? Neurotox Res 2022; 40:1096-1102. [PMID: 35666433 DOI: 10.1007/s12640-022-00526-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 05/10/2022] [Accepted: 05/26/2022] [Indexed: 10/18/2022]
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder characterized by dopaminergic neurodegeneration and deposition of alpha-synuclein. Mechanisms associated with PD etiology include oxidative stress, apoptosis, autophagy, and abnormalities in neurotransmission, to name a few. Drugs used to treat PD have shown significant limitations in their efficacy. Therefore, recent focus has been placed on the potential of active plant ingredients as alternative, complementary, and efficient treatments. Berberine is an isoquinoline alkaloid that has shown promise as a pharmacological treatment in PD, given its ability to modulate several molecular pathway associated with the disease. Here, we review contemporary knowledge supporting the need to further characterize berberine as a potential treatment for PD.
Collapse
Affiliation(s)
- Ehsan Dadgostar
- Behavioral Sciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.,Student Research Committee, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mahsa Moghanlou
- Department of Psychiatry, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mehrnoosh Parvaresh
- Department of Physical Medicine and Rehabilitation, School of Medicine, Isfahan University of Medical Science, Isfahan, Iran
| | - Salimeh Mohammadi
- Anatomical Science Research Center, Institute for Basic Sciences, Kashan University of Medical Sciences, Kashan, Iran
| | - Mohammadali Khandan
- Student Research Committee, Kashan University of Medical Sciences, Kashan, Iran
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Hamed Mirzaei
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Institute for Basic Sciences, Kashan University of Medical Sciences, Kashan, Iran.
| | - Omid Reza Tamtaji
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran. .,Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran.
| |
Collapse
|
2
|
Chang NHS, Kumakura Y, Møller A, Linnet J, Bender D, Doudet DJ, Vafaee MS, Gjedde A. On the learning of addictive behavior: Sensation-seeking propensity predicts dopamine turnover in dorsal striatum. Brain Imaging Behav 2021; 16:355-365. [PMID: 34417966 PMCID: PMC8825434 DOI: 10.1007/s11682-021-00509-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/14/2021] [Indexed: 11/26/2022]
Abstract
We asked if sensation-seeking is linked to premorbid personality characteristics in patients with addictive disorders, or the characteristics follow the sensation-seeking activity. We interpreted the former as a state associated with normal rates of dopamine synthesis, and the latter as a trait of individuals with abnormally high rates of synthesis. We previously determined dopaminergic receptor density in striatum, and we now tested the hypothesis that an elevated dopaminergic condition with increased extracellular dopamine and receptor density follows increased dopamine synthesis capacity in highly sensation-seeking individuals, as measured by positron emission tomography of 18 men with tracer fluorodopa (FDOPA). We detected a site in left caudate nucleus where the volume of distribution of FDOPA-derived metabolites correlated negatively with FDOPA metabolite turnover, consistent with decreased metabolite breakdown in highly sensation-seeking subjects. High rates of sensation-seeking attenuated the dopamine turnover in association with a low rate of dopamine recycling, low dopamine oxidation, and elevated extracellular dopamine and receptors in caudate nucleus. In contrast, low rates of sensation-seeking were associated with rapid dopamine recycling, rapid dopamine oxidation, low extracellular dopamine, and low receptor density. We conclude that the modulation of dopaminergic neurotransmission associated with sensation-seeking is a state of sensation-seeking, rather than a trait of personality following abnormal regulation of dopaminergic neurotransmission.
Collapse
Affiliation(s)
- Natalie Hong Siu Chang
- Department of Clinical Research, University of Southern Denmark, Odense C, DK-5000 Denmark
| | - Yoshitaka Kumakura
- Department of Diagnostic Radiology and Nuclear Medicine, Saitama Medical University, 1981 Kamoda, Kawagoe, Saitama 350-8550 Japan
| | - Arne Møller
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, DK-8200 Aarhus N, Denmark
| | - Jakob Linnet
- Gambling Disorder & BED Clinic, Department of Occupational and Environmental Medicine, Odense University Hospital, Odense C, Dk-5000 Denmark
| | - Dirk Bender
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, DK-8200 Aarhus N, Denmark
| | - Doris J. Doudet
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, DK-8200 Aarhus N, Denmark
- Department of Medicine, Division of Neurology, University of British Columbia, Vancouver, B.C. V6T 2B5 Canada
| | - Manouchehr Seyedi Vafaee
- Department of Clinical Research, BRIDGE, University of Southern Denmark, Odense M, DK-5230 Denmark
| | - Albert Gjedde
- Department of Neuroscience, University of Copenhagen, Copenhagen, DK-2200 Denmark
- Department of Clinical Medicine, University of Southern Denmark, Odense C, DK-5000 Denmark
- Translational Neuropsychiatry Unit, Aarhus University, Aarhus, DK-8000 Denmark
| |
Collapse
|
3
|
Oral berberine improves brain dopa/dopamine levels to ameliorate Parkinson's disease by regulating gut microbiota. Signal Transduct Target Ther 2021; 6:77. [PMID: 33623004 PMCID: PMC7902645 DOI: 10.1038/s41392-020-00456-5] [Citation(s) in RCA: 114] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/20/2020] [Accepted: 12/09/2020] [Indexed: 12/15/2022] Open
Abstract
The phenylalanine–tyrosine–dopa–dopamine pathway provides dopamine to the brain. In this process, tyrosine hydroxylase (TH) is the rate-limiting enzyme that hydroxylates tyrosine and generates levodopa (l-dopa) with tetrahydrobiopterin (BH4) as a coenzyme. Here, we show that oral berberine (BBR) might supply H• through dihydroberberine (reduced BBR produced by bacterial nitroreductase) and promote the production of BH4 from dihydrobiopterin; the increased BH4 enhances TH activity, which accelerates the production of l-dopa by the gut bacteria. Oral BBR acts in a way similar to vitamins. The l-dopa produced by the intestinal bacteria enters the brain through the circulation and is transformed to dopamine. To verify the gut–brain dialog activated by BBR’s effect, Enterococcus faecalis or Enterococcus faecium was transplanted into Parkinson’s disease (PD) mice. The bacteria significantly increased brain dopamine and ameliorated PD manifestation in mice; additionally, combination of BBR with bacteria showed better therapeutic effect than that with bacteria alone. Moreover, 2,4,6-trimethyl-pyranylium tetrafluoroborate (TMP-TFB)-derivatized matrix-assisted laser desorption mass spectrometry (MALDI-MS) imaging of dopamine identified elevated striatal dopamine levels in mouse brains with oral Enterococcus, and BBR strengthened the imaging intensity of brain dopamine. These results demonstrated that BBR was an agonist of TH in Enterococcus and could lead to the production of l-dopa in the gut. Furthermore, a study of 28 patients with hyperlipidemia confirmed that oral BBR increased blood/fecal l-dopa by the intestinal bacteria. Hence, BBR might improve the brain function by upregulating the biosynthesis of l-dopa in the gut microbiota through a vitamin-like effect.
Collapse
|
4
|
The role of dopamine dysregulation and evidence for the transdiagnostic nature of elevated dopamine synthesis in psychosis: a positron emission tomography (PET) study comparing schizophrenia, delusional disorder, and other psychotic disorders. Neuropsychopharmacology 2020; 45:1870-1876. [PMID: 32612207 PMCID: PMC7608388 DOI: 10.1038/s41386-020-0740-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 05/22/2020] [Accepted: 05/29/2020] [Indexed: 12/22/2022]
Abstract
There have been few studies performed to examine the pathophysiological differences between different types of psychosis, such as between delusional disorder (DD) and schizophrenia (SZ). Notably, despite the different clinical characteristics of DD and schizophrenia (SZ), antipsychotics are deemed equally effective pharmaceutical treatments for both conditions. In this context, dopamine dysregulation may be transdiagnostic of the pathophysiology of psychotic disorders such as DD and SZ. In this study, an examination is made of the dopamine synthesis capacity (DSC) of patients with SZ, DD, other psychotic disorders, and the DSC of healthy subjects. Fifty-four subjects were recruited to the study, comprising 35 subjects with first-episode psychosis (11 DD, 12 SZ, 12 other psychotic disorders) and 19 healthy controls. All received an 18F-DOPA positron emission tomography (PET)/magnetic resonance (MR) scan to measure DSC (Kocc;30-60 value) within 1 month of starting antipsychotic treatment. Clinical assessments were also made, which included Positive and Negative Syndrome Scale (PANSS) measurements. The mean Kocc;30-60 was significantly greater in the caudate region of subjects in the DD group (ES = 0.83, corrected p = 0.048), the SZ group (ES = 1.40, corrected p = 0.003) and the other psychotic disorder group (ES = 1.34, corrected p = 0.0045), compared to that of the control group. These data indicate that DD, SZ, and other psychotic disorders have similar dysregulated mechanisms of dopamine synthesis, which supports the utility of abnormal dopamine synthesis in transdiagnoses of these psychotic conditions.
Collapse
|
5
|
Katthagen T, Kaminski J, Heinz A, Buchert R, Schlagenhauf F. Striatal Dopamine and Reward Prediction Error Signaling in Unmedicated Schizophrenia Patients. Schizophr Bull 2020; 46:1535-1546. [PMID: 32318717 PMCID: PMC7751190 DOI: 10.1093/schbul/sbaa055] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Increased striatal dopamine synthesis capacity has consistently been reported in patients with schizophrenia. However, the mechanism translating this into behavior and symptoms remains unclear. It has been proposed that heightened striatal dopamine may blunt dopaminergic reward prediction error signaling during reinforcement learning. In this study, we investigated striatal dopamine synthesis capacity, reward prediction errors, and their association in unmedicated schizophrenia patients (n = 19) and healthy controls (n = 23). They took part in FDOPA-PET and underwent functional magnetic resonance imaging (fMRI) scanning, where they performed a reversal-learning paradigm. The groups were compared regarding dopamine synthesis capacity (Kicer), fMRI neural prediction error signals, and the correlation of both. Patients did not differ from controls with respect to striatal Kicer. Taking into account, comorbid alcohol abuse revealed that patients without such abuse showed elevated Kicer in the associative striatum, while those with abuse did not differ from controls. Comparing all patients to controls, patients performed worse during reversal learning and displayed reduced prediction error signaling in the ventral striatum. In controls, Kicer in the limbic striatum correlated with higher reward prediction error signaling, while there was no significant association in patients. Kicer in the associative striatum correlated with higher positive symptoms and blunted reward prediction error signaling was associated with negative symptoms. Our results suggest a dissociation between striatal subregions and symptom domains, with elevated dopamine synthesis capacity in the associative striatum contributing to positive symptoms while blunted prediction error signaling in the ventral striatum related to negative symptoms.
Collapse
Affiliation(s)
- Teresa Katthagen
- Department of Psychiatry and Psychotherapy, Charité Campus Mitte, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany,To whom correspondence should be addressed; Department of Psychiatry and Psychotherapy, Charité – Universitätsmedizin Berlin, Campus Charité Mitte, Charitéplatz 1, 10117 Berlin, Germany; tel: +49-(0)-30-450-517389, fax: +49-(0)-30-450-517962, e-mail:
| | - Jakob Kaminski
- Department of Psychiatry and Psychotherapy, Charité Campus Mitte, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany,Berlin Institute of Health, Berlin, Germany,Max-Planck-Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Andreas Heinz
- Department of Psychiatry and Psychotherapy, Charité Campus Mitte, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany,Berlin Institute of Health, Berlin, Germany,Cluster of Excellence NeuroCure, Charité-Universitätsmedizin, Berlin, Germany
| | - Ralph Buchert
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Florian Schlagenhauf
- Department of Psychiatry and Psychotherapy, Charité Campus Mitte, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany,Max-Planck-Institute for Human Cognitive and Brain Sciences, Leipzig, Germany,Bernstein Center for Computational Neuroscience, Berlin, Germany
| |
Collapse
|
6
|
Avram M, Brandl F, Cabello J, Leucht C, Scherr M, Mustafa M, Leucht S, Ziegler S, Sorg C. Reduced striatal dopamine synthesis capacity in patients with schizophrenia during remission of positive symptoms. Brain 2020; 142:1813-1826. [PMID: 31135051 DOI: 10.1093/brain/awz093] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 02/07/2019] [Accepted: 02/12/2019] [Indexed: 02/07/2023] Open
Abstract
While there is consistent evidence for increased presynaptic dopamine synthesis capacity in the striatum of patients with schizophrenia during psychosis, it is unclear whether this also holds for patients during psychotic remission. This study investigates whether striatal dopamine synthesis capacity is altered in patients with schizophrenia during symptomatic remission of positive symptoms, and whether potential alterations relate to symptoms other than positive, such as cognitive difficulties. Twenty-three patients with schizophrenia in symptomatic remission of positive symptoms according to Andreasen, and 24 healthy controls underwent 18F-DOPA-PET and behavioural-cognitive assessment. Imaging data were analysed with voxel-wise Patlak modelling with cerebellum as reference region, resulting in the influx constant kicer reflecting dopamine synthesis capacity. For the whole striatum and its subdivisions (i.e. limbic, associative, and sensorimotor), averaged regional kicer values were calculated, compared across groups, and correlated with behavioural-cognitive scores, including a mediation analysis. Patients had negative symptoms (Positive and Negative Syndrome Scale-negative 14.13 ± 5.91) and cognitive difficulties, i.e. they performed worse than controls in Trail-Making-Test-B (TMT-B; P = 0.01). Furthermore, kicer was reduced in patients for whole striatum (P = 0.004) and associative (P = 0.002) and sensorimotor subdivisions (P = 0.007). In patients, whole striatum kicer was negatively correlated with TMT-B (rho = -0.42, P = 0.04; i.e. the lower striatal kicer, the worse the cognitive performance). Mediation analysis showed that striatal kicer mediated the group difference in TMT-B. Results demonstrate that patients with schizophrenia in symptomatic remission of positive symptoms have decreased striatal dopamine synthesis capacity, which mediates the disorder's impact on cognitive difficulties. Data suggest that striatal dopamine dysfunction contributes to cognitive difficulties in schizophrenia.
Collapse
Affiliation(s)
- Mihai Avram
- Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.,TUM-NIC Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.,Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Felix Brandl
- Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.,TUM-NIC Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.,Department of Psychiatry, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Jorge Cabello
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Claudia Leucht
- Department of Psychiatry, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Martin Scherr
- Department of Psychiatry, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Mona Mustafa
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Stefan Leucht
- Department of Psychiatry, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.,Department of Psychosis Studies, King's College London, UK
| | - Sibylle Ziegler
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.,Department of Nuclear Medicine, University Hospital, LMU Munich, Munich, Germany
| | - Christian Sorg
- Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.,TUM-NIC Neuroimaging Center, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.,Department of Psychiatry, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| |
Collapse
|
7
|
Abi-Dargham A. From "bedside" to "bench" and back: A translational approach to studying dopamine dysfunction in schizophrenia. Neurosci Biobehav Rev 2018; 110:174-179. [PMID: 30528375 DOI: 10.1016/j.neubiorev.2018.12.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 11/25/2018] [Accepted: 12/04/2018] [Indexed: 01/07/2023]
Abstract
Despite multiple lines of research, a mechanistic understanding of schizophrenia remains elusive. Neuroimaging studies have yielded observations that can be used in translational studies in animals to attempt to uncover their cellular and circuit basis and their significance for the diseased human brain. Enhanced D2 stimulation in the striatum is a well replicated and established observation in patients with schizophrenia. This "bedside" observation was reproduced "at the bench" level by creating a transgenic mouse overexpressing D2 receptors in dorsal striatum (D2R-OE mouse). The D2R-OE mouse showed multiple behavioral, molecular, electrophysiological and anatomical alterations. Some of these are consistent with findings in patients with schizophrenia, providing construct validity to the model and mechanistic insights for the observations made in humans. Other findings were novel, and provide an opportunity for a reverse translational effort back into the clinic. In this review we will summarize the process of translation and back translation from the D2R-OE mouse and describe the insights into the pathophysiology of the disease gained through this type of translational work.
Collapse
Affiliation(s)
- Anissa Abi-Dargham
- Departments of Psychiatry and Radiology, Stony Brook School of Medicine, HSC-T10-087H, 101 Nicolls Road, Stony Brook, NY, 11794-8101, United States.
| |
Collapse
|
8
|
Langhoff W, Riggs A, Hinow P. Scaling behavior of drug transport and absorption in in silico cerebral capillary networks. PLoS One 2018; 13:e0200266. [PMID: 29990324 PMCID: PMC6039031 DOI: 10.1371/journal.pone.0200266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 06/23/2018] [Indexed: 12/27/2022] Open
Abstract
Drug delivery to the brain is challenging due to the presence of the blood-brain barrier. Mathematical modeling and simulation are essential tools for the deeper understanding of transport processes in the blood, across the blood-brain barrier and within the tissue. Here we present a mathematical model for drug delivery through capillary networks with increasingly complex topologies with the goal to understand the scaling behavior of model predictions on a coarse-to-fine sequence of grids. We apply our model to the delivery of L-Dopa, the primary drug used in the therapy of Parkinson’s Disease. Our model replicates observed blood flow rates and ratios between plasma and tissue concentrations. We propose an optimal network grain size for the simulation of tissue volumes of 1 cm3 that allows to make reliable predictions with reasonable computational costs.
Collapse
Affiliation(s)
- William Langhoff
- Department of Mathematical Sciences, University of Wisconsin - Milwaukee, Milwaukee, WI 53201-0413, United States of America
| | - Alexander Riggs
- Department of Mathematical Sciences, University of Wisconsin - Milwaukee, Milwaukee, WI 53201-0413, United States of America
| | - Peter Hinow
- Department of Mathematical Sciences, University of Wisconsin - Milwaukee, Milwaukee, WI 53201-0413, United States of America
| |
Collapse
|
9
|
Dall AM, Danielsen EH, Sørensen JC, Andersen F, Møller A, Zimmer J, Gjedde AH, Cumming P, Zimmer J, Brevig T, Dall AM, Meyer M, Pedersen EB, Gjedde A, Danielsen EH, Cumming P, Andersen F, Bender D, Falborg L, Gee A, Gillings NM, Hansen SB, Hermansen F, Jørgensen HA, Munk O, Poulsen PH, Rodell AB, Sakoh M, Simonsen CZ, Smith DF, Sørensen JC, Østergård L, Moller A, Johansen TE. Quantitative [18F]Fluorodopa/PET and Histology of Fetal Mesencephalic Dopaminergic Grafts to the Striatum of MPTP-Poisoned Minipigs. Cell Transplant 2017. [DOI: 10.3727/000000002783985314] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The functional restoration of the dopamine innervation of striatum in MPTP-poisoned Göttingen minipigs was assessed for 6 months following grafting of fetal pig mesencephalic neurons. Pigs were assigned to a normal control group and a MPTP-poisoned group, members of which received no further treatment, or which received bilateral grafts to the striatum of tissue blocks harvested from E28 fetal pig mesencephalon with and without immunosuppressive treatment after grafting, or with additional co-grafting with immortalized rat neural cells transfected to produce GDNF. In the baseline condition, and again at 3 and 6 months postsurgery, all animals were subjected to quantitative [18F]fluorodopa PET scans and testing for motor impairment. At the end of 6 months, tyrosine hydroxylase (TH)-containing neurons were counted in the grafts by stereological methods. The MPTP poisoning persistently reduced the magnitude of k3D, the relative activity of DOPA decarboxylase in striatum, by 60%. Grafting restored the rate of [18F]fluorodopa decarboxylation to the normal range, and normalized the scores in motor function. The biochemical and functional recovery was associated with survival of approximately 100,000 TH-positive graft neurons in each hemisphere. Immunosuppression did not impart a greater recovery of [18F]fluorodopa uptake, nor were the number of TH-positive graft neurons or the volumes of the grafts increased in the immunosuppressed group. Contrary to expectation, co-grafting of transfected GDNF-expressing HiB5 cells, a rat-derived neural cell line, tended to impair the survival of the grafts with the lowest values for graft volumes, TH-positive cell numbers, behavioral scores, and relative DOPA decarboxylase activity. From the results we conclude that pig ventral mesencephalic allografts can restore functional dopamine innervation in adult MPTP-lesioned minipigs.
Collapse
Affiliation(s)
- Annette Møller Dall
- Department of Anatomy and Neurobiology, University of Southern Denmark, 5000 Odense C, Denmark
| | | | | | | | | | - Jens Zimmer
- Department of Anatomy and Neurobiology, University of Southern Denmark, 5000 Odense C, Denmark
| | - Albert H. Gjedde
- Department of Anatomy and Neurobiology, University of Southern Denmark, 5000 Odense C, Denmark
- McGill University, Montreal, Quebec, Canada
| | - Paul Cumming
- PET Centre, Aarhus General Hospital, 8000 Aarhus C, Denmark
| | - J. Zimmer
- Department of Anatomy and Neurobiology, SDU Odense University
| | - T. Brevig
- Department of Anatomy and Neurobiology, SDU Odense University
| | - A. M. Dall
- Department of Anatomy and Neurobiology, SDU Odense University
| | - M. Meyer
- Department of Anatomy and Neurobiology, SDU Odense University
| | - E. B. Pedersen
- Department of Anatomy and Neurobiology, SDU Odense University
| | - A. Gjedde
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | - E. H. Danielsen
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | - P. Cumming
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | - F. Andersen
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | - D. Bender
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | - L. Falborg
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | - A. Gee
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | - N. M. Gillings
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | - S. B. Hansen
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | - F. Hermansen
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | - H. A. Jørgensen
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | - O. Munk
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | - P. H. Poulsen
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | - A. B. Rodell
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | - M. Sakoh
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | - C. Z. Simonsen
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | - D. F. Smith
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | - J. C. Sørensen
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | - L. Østergård
- PET-Center and Departments of Neuroradiology, Neurosurgery, Neuroanaesthesia, and Biological Psychiatry, Aarhus University Hospital
| | | | | | | |
Collapse
|
10
|
|
11
|
Weinstein JJ, Chohan MO, Slifstein M, Kegeles LS, Moore H, Abi-Dargham A. Pathway-Specific Dopamine Abnormalities in Schizophrenia. Biol Psychiatry 2017; 81:31-42. [PMID: 27206569 PMCID: PMC5177794 DOI: 10.1016/j.biopsych.2016.03.2104] [Citation(s) in RCA: 186] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 03/21/2016] [Accepted: 03/25/2016] [Indexed: 02/08/2023]
Abstract
In light of the clinical evidence implicating dopamine in schizophrenia and the prominent hypotheses put forth regarding alterations in dopaminergic transmission in this disease, molecular imaging has been used to examine multiple aspects of the dopaminergic system. We review the imaging methods used and compare the findings across the different molecular targets. Findings have converged to suggest early dysregulation in the striatum, especially in the rostral caudate, manifesting as excess synthesis and release. Recent data showed deficit extending to most cortical regions and even to other extrastriatal subcortical regions not previously considered to be "hypodopaminergic" in schizophrenia. These findings yield a new topography for the dopaminergic dysregulation in schizophrenia. We discuss the dopaminergic innervation within the individual projection fields to provide a topographical map of this dual dysregulation and explore potential cellular and circuit-based mechanisms for brain region-dependent alterations in dopaminergic parameters. This refined knowledge is essential to better guide translational studies and efforts in early drug development.
Collapse
Affiliation(s)
- Jodi J. Weinstein
- Columbia University Department of Psychiatry, New York, NY,New York State Psychiatric Institute Division of Translational Imaging,Corresponding author: Jodi Weinstein, New York State Psychiatric Institute, 1051 Riverside Drive, Unit 31, New York, New York 10032, +1-646-774-8123,
| | - Muhammad O. Chohan
- New York State Psychiatric Institute Division of Integrative Neuroscience
| | - Mark Slifstein
- Columbia University Department of Psychiatry, New York, NY,New York State Psychiatric Institute Division of Translational Imaging
| | - Lawrence S. Kegeles
- Columbia University Department of Psychiatry, New York, NY,New York State Psychiatric Institute Division of Translational Imaging
| | - Holly Moore
- Columbia University Department of Psychiatry, New York, NY,New York State Psychiatric Institute Division of Integrative Neuroscience
| | - Anissa Abi-Dargham
- Columbia University Department of Psychiatry, New York, NY,New York State Psychiatric Institute Division of Translational Imaging
| |
Collapse
|
12
|
Hinow P, Radunskaya A, Mackay SM, Reynolds JNJ, Schroeder M, Tan EW, Tucker IG. Signaled drug delivery and transport across the blood-brain barrier. J Liposome Res 2015; 26:233-45. [PMID: 26572864 DOI: 10.3109/08982104.2015.1102277] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We use a mathematical model to describe the delivery of a drug to a specific region of the brain. The drug is carried by liposomes that can release their cargo by application of focused ultrasound (US). Thereupon, the drug is absorbed through the endothelial cells that line the brain capillaries and form the physiologically important blood-brain barrier (BBB). We present a compartmental model of a capillary that is able to capture the complex binding and transport processes the drug undergoes in the blood plasma and at the BBB. We apply this model to the delivery of levodopa (L-dopa, used to treat Parkinson's disease) and doxorubicin (an anticancer agent). The goal is to optimize the delivery of drug while at the same time minimizing possible side effects of the US.
Collapse
Affiliation(s)
- Peter Hinow
- a Department of Mathematical Sciences , University of Wisconsin , Milwaukee , WI , USA
| | - Ami Radunskaya
- b Department of Mathematics , Pomona College , Claremont , CA , USA
| | - Sean M Mackay
- c Department of Chemistry , University of Otago , Dunedin , New Zealand
| | - John N J Reynolds
- d Department of Anatomy and the Brain Health Research Centre , University of Otago , Dunedin , New Zealand
| | - Morgan Schroeder
- e Department of Biology , University of Oregon , Eugene , OR , USA , and
| | - Eng Wui Tan
- c Department of Chemistry , University of Otago , Dunedin , New Zealand
| | - Ian G Tucker
- f New Zealand's National School of Pharmacy, University of Otago , Dunedin , New Zealand
| |
Collapse
|
13
|
Acute and sustained effects of methylphenidate on cognition and presynaptic dopamine metabolism: an [18F]FDOPA PET study. J Neurosci 2015; 34:14769-76. [PMID: 25355228 DOI: 10.1523/jneurosci.1560-14.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Methylphenidate (MPH) inhibits the reuptake of dopamine and noradrenaline. PET studies with MPH challenge show increased competition at postsynaptic D2/3-receptors, thus indirectly revealing presynaptic dopamine release. We used [(18)F]fluorodopamine ([(18)F]FDOPA)-PET in conjunction with the inlet-outlet model (IOM) of Kumakura et al. (2007) to investigate acute and long-term changes in dopamine synthesis capacity and turnover in nigrostriatal fibers of healthy subjects with MPH challenge. Twenty healthy human females underwent two dynamic [(18)F]FDOPA PET scans (124 min; slow bolus-injection; arterial blood sampling), with one scan in untreated baseline condition and the other after MPH administration (0.5 mg/kg, p.o.), in randomized order. Subjects underwent cognitive testing at each PET session. Time activity curves were obtained for ventral putamen and caudate and were analyzed according to the IOM to obtain the regional net-uptake of [(18)F]FDOPA (K; dopamine synthesis capacity) as well as the [(18)F]fluorodopamine washout rate (kloss, index of dopamine turnover). MPH substantially decreased kloss in putamen (-22%; p = 0.003). In the reversed treatment order group (MPH/no drug), K was increased by 18% at no drug follow-up. The magnitude of K at the no drug baseline correlated with cognitive parameters. Furthermore, individual kloss changes correlated with altered cognitive performance under MPH. [(18)F]FDOPA PET in combination with the IOM detects an MPH-evoked decrease in striatal dopamine turnover, in accordance with the known acute pharmacodynamics of MPH. Furthermore, the scan-ordering effect on K suggested that a single MPH challenge persistently increased striatal dopamine synthesis capacity. Attenuation of dopamine turnover by MPH is linked to enhanced cognitive performance in healthy females.
Collapse
|
14
|
Piel M, Vernaleken I, Rösch F. Positron Emission Tomography in CNS Drug Discovery and Drug Monitoring. J Med Chem 2014; 57:9232-58. [DOI: 10.1021/jm5001858] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Markus Piel
- Institute
of Nuclear Chemistry, Johannes Gutenberg-University, Fritz-Strassmann-Weg 2, D-55128 Mainz, Germany
| | - Ingo Vernaleken
- Department
of Psychiatry, Psychotherapy, and Psychosomatics, RWTH Aachen University, Pauwelsstraße 30, D-52074 Aachen, Germany
| | - Frank Rösch
- Institute
of Nuclear Chemistry, Johannes Gutenberg-University, Fritz-Strassmann-Weg 2, D-55128 Mainz, Germany
| |
Collapse
|
15
|
Bonoldi I, Howes OD. Presynaptic dopaminergic function: implications for understanding treatment response in psychosis. CNS Drugs 2014; 28:649-63. [PMID: 24919790 DOI: 10.1007/s40263-014-0177-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
All current antipsychotic drugs block dopamine (DA) receptors, but the nature of the DA dysfunction in schizophrenia has not been clear. However, consistent evidence now shows that presynaptic dopaminergic function is altered in schizophrenia, specifically in terms of increased DA synthesis capacity, baseline synaptic DA levels, and DA release. Furthermore, presynaptic dopaminergic function is already elevated in prodromal patients who later developed the disorder. Currently available antipsychotics act on postsynaptic receptors, not targeting presynaptic DA abnormalities. This has implications for understanding response and developing new treatments. The lack of normalization of the abnormal presynaptic function could explain why discontinuation is likely to lead to relapse, because the major dopaminergic function persists, meaning that once treatment stops there is nothing to oppose the dysregulated dopamine function reinstating symptoms. Furthermore, it suggests that drugs that target presynaptic dopaminergic function may constitute new treatment possibilities for schizophrenic patients, in particular, for those in whom antipsychotics are poorly effective. In addition, the longitudinal changes with the onset of psychosis indicate the potential to target a defined dynamic neurochemical abnormality to prevent the onset of psychosis.
Collapse
Affiliation(s)
- I Bonoldi
- Department of Psychosis Studies, Institute of Psychiatry, King's College of London, De Crespigny Park 16, London, SE5 8AF, UK,
| | | |
Collapse
|
16
|
Influence of O-methylated metabolite penetrating the blood-brain barrier to estimation of dopamine synthesis capacity in human L-[β-(11)C]DOPA PET. J Cereb Blood Flow Metab 2014; 34:268-74. [PMID: 24192636 PMCID: PMC3915201 DOI: 10.1038/jcbfm.2013.187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Revised: 09/16/2013] [Accepted: 10/09/2013] [Indexed: 11/08/2022]
Abstract
O-methyl metabolite (L-[β-(11)C]OMD) of (11)C-labeled L-3,4-dihydroxyphenylalanine (L-[β-(11)C]DOPA) can penetrate into brain tissue through the blood-brain barrier, and can complicate the estimation of dopamine synthesis capacity by positron emission tomography (PET) study with L-[β-(11)C]DOPA. We evaluated the impact of L-[β-(11)C]OMD on the estimation of the dopamine synthesis capacity in a human L-[β-(11)C]DOPA PET study. The metabolite correction with mathematical modeling of L-[β-(11)C]OMD kinetics in a reference region without decarboxylation and further metabolism, proposed by a previous [(18)F]FDOPA PET study, were implemented to estimate radioactivity of tissue L-[β-(11)C]OMD in 10 normal volunteers. The component of L-[β-(11)C]OMD in tissue time-activity curves (TACs) in 10 regions were subtracted by the estimated radioactivity of L-[β-(11)C]OMD. To evaluate the influence of omitting blood sampling and metabolite correction, relative dopamine synthesis rate (kref) was estimated by Gjedde-Patlak analysis with reference tissue input function, as well as the net dopamine synthesis rate (Ki) by Gjedde-Patlak analysis with the arterial input function and TAC without and with metabolite correction. Overestimation of Ki was observed without metabolite correction. However, the kref and Ki with metabolite correction were significantly correlated. These data suggest that the influence of L-[β-(11)C]OMD is minimal for the estimation of kref as dopamine synthesis capacity.
Collapse
|
17
|
Abstract
Cerebral dopamine (DA) transmission is thought to be an important modulator for the development and occurrence of aggressive behavior. However, the link between aggression and DA transmission in humans has not been investigated using molecular imaging and standardized behavioral tasks. We investigated aggression as a function of DA transmission in a group of (N = 21) healthy male volunteers undergoing 6-[18F]-fluoro-L-DOPA (FDOPA)-positron emission tomography (PET) and a modified version of the Point Subtraction Aggression Paradigm (PSAP). This task measures aggressive behavior during a monetary reward-related paradigm, where a putative adversary habitually tries to cheat. The participant can react in three ways (i.e., money substraction of the putative opponent [aggressive punishment], pressing a defense button, or continuing his money-making behavior). FDOPA-PET was analyzed using a steady-state model yielding estimates of the DA-synthesis capacity (K), the turnover of tracer DA formed in living brain (kloss), and the tracer distribution volume (Vd), which is an index of DA storage capacity. Significant negative correlations between PSAP aggressive responses and the DA-synthesis capacity were present in several regions, most prominently in the midbrain (r = -0.640; p = 0.002). Lower degrees of aggressive responses were associated with higher DA storage capacity in the striatum and midbrain. Additionally, there was a significant positive correlation between the investment into monetary incentive responses on the PSAP and DA-synthesis capacity, notably in the midbrain (r = +0.618, p = 0.003). The results suggest that individuals with low DA transmission capacity are more vulnerable to reactive/impulsive aggression in response to provocation.
Collapse
|
18
|
Schlagenhauf F, Rapp MA, Huys QJM, Beck A, Wüstenberg T, Deserno L, Buchholz HG, Kalbitzer J, Buchert R, Bauer M, Kienast T, Cumming P, Plotkin M, Kumakura Y, Grace AA, Dolan RJ, Heinz A. Ventral striatal prediction error signaling is associated with dopamine synthesis capacity and fluid intelligence. Hum Brain Mapp 2012; 34:1490-9. [PMID: 22344813 DOI: 10.1002/hbm.22000] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 10/11/2011] [Accepted: 11/08/2011] [Indexed: 11/10/2022] Open
Abstract
Fluid intelligence represents the capacity for flexible problem solving and rapid behavioral adaptation. Rewards drive flexible behavioral adaptation, in part via a teaching signal expressed as reward prediction errors in the ventral striatum, which has been associated with phasic dopamine release in animal studies. We examined a sample of 28 healthy male adults using multimodal imaging and biological parametric mapping with (1) functional magnetic resonance imaging during a reversal learning task and (2) in a subsample of 17 subjects also with positron emission tomography using 6-[(18) F]fluoro-L-DOPA to assess dopamine synthesis capacity. Fluid intelligence was measured using a battery of nine standard neuropsychological tests. Ventral striatal BOLD correlates of reward prediction errors were positively correlated with fluid intelligence and, in the right ventral striatum, also inversely correlated with dopamine synthesis capacity (FDOPA K inapp). When exploring aspects of fluid intelligence, we observed that prediction error signaling correlates with complex attention and reasoning. These findings indicate that individual differences in the capacity for flexible problem solving relate to ventral striatal activation during reward-related learning, which in turn proved to be inversely associated with ventral striatal dopamine synthesis capacity.
Collapse
Affiliation(s)
- Florian Schlagenhauf
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité-Universitätsmedizin Berlin, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Kuepper R, Skinbjerg M, Abi-Dargham A. The dopamine dysfunction in schizophrenia revisited: new insights into topography and course. Handb Exp Pharmacol 2012:1-26. [PMID: 23129326 DOI: 10.1007/978-3-642-25761-2_1] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Schizophrenia has long been associated with an imbalance in dopamine (DA) neurotransmission, and brain imaging has played an important role in advancing our knowledge and providing evidence for the dopaminergic abnormalities. This chapter reviews the evidence for DA dysfunction in different brain regions in schizophrenia, in particular striatal, extrastriatal, and prefrontal regions, with emphasis on recently published findings. As opposed to the traditional view that most striatal dopaminergic excess, associated with the positive symptoms of schizophrenia, involves the dopaminergic mesolimbic pathway, recent evidence points to the nigrostriatal pathway as the area of highest dysregulation. Furthermore, evidence from translational research suggests that dopaminergic excess may be present in the prodromal phase, and may by itself, as suggested by the phenotype observed in transgenic mice with developmental overexpression of dorso-striatal D(2) receptors, be an early pathogenic condition, leading to irreversible cortical dysfunction.
Collapse
Affiliation(s)
- Rebecca Kuepper
- Department of Psychiatry and Psychology, Maastricht University Medical Center, Maastricht, The Netherlands
| | | | | |
Collapse
|
20
|
Popkov A, De Spiegeleer B. Chiral nickel(ii) complexes in the preparation of11C- and18F-labelled enantiomerically pure α-amino acids. Dalton Trans 2012; 41:1430-40. [PMID: 22159040 DOI: 10.1039/c1dt11675d] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Alexander Popkov
- Department of Cognitive Research and Tomographic Imaging Methods, Samo University in Pardubice, Na Klínku 1082, 530 06, Pardubice, Czech Republic
| | | |
Collapse
|
21
|
Comparison of dopamine turnover, dopamine influx constant and activity ratio of striatum and occipital brain with 18F-dopa brain PET in normal controls and patients with Parkinson’s disease. Eur J Nucl Med Mol Imaging 2011; 38:1550-9. [DOI: 10.1007/s00259-011-1819-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 04/06/2011] [Indexed: 11/25/2022]
|
22
|
Matsubara K, Watabe H, Kumakura Y, Hayashi T, Endres CJ, Minato K, Iida H. Sensitivity of kinetic macro parameters to changes in dopamine synthesis, storage, and metabolism: a simulation study for [¹⁸F]FDOPA PET by a model with detailed dopamine pathway. Synapse 2011; 65:751-62. [PMID: 21190220 DOI: 10.1002/syn.20899] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Accepted: 12/02/2010] [Indexed: 11/08/2022]
Abstract
Quantitative interpretation of brain [¹⁸F]FDOPA PET data has been made possible by several kinetic modeling approaches, which are based on different assumptions about complex [¹⁸F]FDOPA metabolic pathways in brain tissue. Simple kinetic macro parameters are often utilized to quantitatively evaluate metabolic and physiological processes of interest, which may include DDC activity, vesicular storage, and catabolism from (18) F-labeled dopamine to DOPAC and HVA. A macro parameter most sensitive to the changes of these processes would be potentially beneficial to identify impaired processes in a neurodegenerative disorder such as Parkinson's disease. The purpose of this study is a systematic comparison of several [¹⁸F]FDOPA macro parameters in terms of sensitivities to process-specific changes in simulated time-activity curve (TAC) data of [¹⁸F]FDOPA PET. We introduced a multiple-compartment kinetic model to simulate PET TACs with physiological changes in the dopamine pathway. TACs in the alteration of dopamine synthesis, storage, and metabolism were simulated with a plasma input function obtained by a non-human primate [¹⁸F]FDOPA PET study. Kinetic macro parameters were calculated using three conventional linear approaches (Gjedde-Patlak, Logan, and Kumakura methods). For simulated changes in dopamine storage and metabolism, the slow clearance rate (k(loss) ) as calculated by the Kumakura method showed the highest sensitivity to these changes. Although k(loss) performed well at typical ROI noise levels, there was large bias at high noise level. In contrast, for simulated changes in DDC activity it was found that K(i) and V(T), estimated by Gjedde-Patlak and Logan method respectively, have better performance than k(loss).
Collapse
Affiliation(s)
- Keisuke Matsubara
- Department of Bioinformatics and Genomics, Graduate School of Information Science, Nara Institute of Science and Technology, Takayama, Ikoma, Nara 630-0192, Japan
| | | | | | | | | | | | | |
Collapse
|
23
|
Okada M, Nakao R, Hosoi R, Zhang MR, Fukumura T, Suzuki K, Inoue O. Microdialysis with radiometric monitoring of L-[β-11C]DOPA to assess dopaminergic metabolism: effect of inhibitors of L-amino acid decarboxylase, monoamine oxidase, and catechol-O-methyltransferase on rat striatal dialysate. J Cereb Blood Flow Metab 2011; 31:124-31. [PMID: 20407462 PMCID: PMC3049477 DOI: 10.1038/jcbfm.2010.58] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The catecholamine, dopamine (DA), is synthesized from 3,4-dihydroxy-L-phenylalanine (L-DOPA) by aromatic L-amino acid decarboxylase (AADC). Dopamine metabolism is regulated by monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT). To measure dopaminergic metabolism, we used microdialysis with radiometric detection to monitor L-[β-(11)C]DOPA metabolites in the extracellular space of the rat striatum. We also evaluated the effects of AADC, MAO, and COMT inhibitors on metabolite profiles. The major early species measured after administration of L-[β-(11)C]DOPA were [(11)C]3,4-dihydroxyphenylacetic acid ([(11)C]DOPAC) and [(11)C]homovanillic acid ([(11)C]HVA) in a 1:1 ratio, which shifted toward [(11)C]HVA with time. An AADC inhibitor increased the uptake of L-[β-(11)C]DOPA and L-3-O-methyl-[(11)C]DOPA and delayed the accumulation of [(11)C]DOPAC and [(11)C]HVA. The MAO and COMT inhibitors increased the production of [(11)C]3-methoxytyramine and [(11)C]DOPAC, respectively. These results reflect the L-DOPA metabolic pathway, suggesting that this method may be useful for assessing dopaminergic metabolism.
Collapse
Affiliation(s)
- Maki Okada
- Molecular Probe Group, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan.
| | | | | | | | | | | | | |
Collapse
|
24
|
Miyake N, Thompson J, Skinbjerg M, Abi-Dargham A. Presynaptic dopamine in schizophrenia. CNS Neurosci Ther 2010; 17:104-9. [PMID: 21199451 DOI: 10.1111/j.1755-5949.2010.00230.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Presynaptic dopamine (DA) transmission has been measured in schizophrenia using different paradigms aimed at providing estimates of the integrity or the activity of the presynaptic dopaminergic neuron. RESEARCHERS HAVE MEASURED: (1) DA synthesis capacity with [(18) F]DOPA, a measure of the activity of dopa decarboxylase, (2) DA release with studies measuring the impact of a DA releasing stimulant challenge on the binding of a D(2) receptor radiotracer, (3) D(2) baseline occupancy by DA, a measure of baseline intrasynaptic DA, assessed by the changes in binding of D(2) radiotracer induced by DA depletion, and (4) the DA and the vesicular monoamine transporters, to assess the integrity of presynaptic terminals. The relationship between DA release and D(2) receptor occupancy at baseline by DA has also been assessed in the same patients. Overall, these different imaging modalities have converged to show a dysregulation of presynaptic dopaminergic activity in schizophrenia, leading to excessive DA release in the striatum, particularly in the projection to the associative striatum, an area of integration between cognitive and limbic cortical inputs. Excessive striatal presynaptic DA is linked to the emergence of acute psychotic symptoms and to their response to treatment in schizophrenia. Understanding the etiology of this dysregulation and its consequences on the rest of the circuitry is important for future drug development.
Collapse
Affiliation(s)
- Nobumi Miyake
- Department of Psychiatry, Columbia University, New York State Psychiatric Institute, New York, NY, USA
| | | | | | | |
Collapse
|
25
|
Patel NH, Vyas NS, Puri BK, Nijran KS, Al-Nahhas A. Positron emission tomography in schizophrenia: a new perspective. J Nucl Med 2010; 51:511-20. [PMID: 20237027 DOI: 10.2967/jnumed.109.066076] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
UNLABELLED PET is an important functional imaging technique that can be used to investigate neurotransmitter receptors and transporters directly by mapping human brain function. PET is increasingly being used greatly to advance our understanding of the neurobiology and pathophysiology of schizophrenia. METHODS This review focuses on the use of PET tracers and kinetic modeling in identifying regional brain abnormalities and regions associated with cognitive functioning in schizophrenia. A variety of PET tracers have been used to identify brain abnormalities, including (11)C, (15)O-water, (18)F-fallypride, and L-3,4-dihydroxy-6-(18)F-fluorophenylalanine ((18)F-FDOPA). RESULTS Some studies have used compartmental modeling to determine tracer binding kinetics. The most consistent findings show a difference in the dopamine content in the prefrontal cortex, anterior cingulate gyrus, and hippocampus between healthy controls and patients with schizophrenia. Studies also show a higher density of D(2) receptors in the striatum and neural brain dysconnectivity. CONCLUSION Future investigations integrating clinical, imaging, genetic, and cognitive aspects are warranted to gain a better understanding of the pathophysiology of this disorder.
Collapse
Affiliation(s)
- Neva H Patel
- Radiological Sciences Unit, Imperial College Healthcare NHS Trust, London, United Kingdom.
| | | | | | | | | |
Collapse
|
26
|
Kumakura Y, Cumming P. PET studies of cerebral levodopa metabolism: a review of clinical findings and modeling approaches. Neuroscientist 2010; 15:635-50. [PMID: 19793723 DOI: 10.1177/1073858409338217] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
[(18)F]Fluoro-3,4-dihydroxyphenyl-L-alanine (FDOPA) was one of the first successful tracers for molecular imaging by positron emission tomography (PET), and has proven immensely valuable for studies of Parkinson's disease. Following intravenous FDOPA injection, the decarboxylated metabolite [(18)F] fluorodopamine is formed and trapped within terminals of the nigrostriatal dopamine neurons; reduction in the simple ratio between striatum and cerebellum is indicative of nigrostriatal degeneration. However, the kinetic analysis of dynamic FDOPA-PET recordings is formidably complex due to the entry into brain of the plasma metabolite O-methyl-FDOPA and due to the eventual washout of decarboxylated metabolites. Linear graphical analysis relative to a reference tissue input function is popular and convenient for routine clinical studies in which serial arterial blood samples are unavailable. This simplified approach has facilitated longitudinal studies in large patient cohorts. Linear graphical analysis relative to the metabolite-corrected arterial FDOPA input yields a more physiological index of FDOPA utilization, the net blood-brain clearance. Using a constrained compartmental model, FDOPA-PET recordings can be used to calculate the relative activity of the enzyme DOPA decarboxylase in living brain. We have extended this approach so as to obtain an index of steady-state trapping of [( 18)F]fluorodopamine in synaptic vesicles. Although simple methods of image analysis are sufficient for the purposes of routine clinical studies, the more complex approaches have revealed hidden aspects of brain dopamine in personality, healthy aging, and in the pathophysiologies of Parkinson's disease and schizophrenia.
Collapse
Affiliation(s)
- Yoshitaka Kumakura
- Department of Nuclear Medicine, Graduate School of Medicine, University of Tokyo, and Research Center for Advanced Science and Technology, the University of Tokyo, Tokyo, Japan.
| | | |
Collapse
|
27
|
Elevated [(18)F]FDOPA utilization in the periaqueductal gray and medial nucleus accumbens of patients with early Parkinson's disease. Neuroimage 2009; 49:2933-9. [PMID: 19941962 DOI: 10.1016/j.neuroimage.2009.11.035] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Revised: 11/12/2009] [Accepted: 11/13/2009] [Indexed: 11/20/2022] Open
Abstract
PET studies with the DOPA decarboxylase substrate 6-[(18)F]fluoro-l-DOPA (FDOPA) reveal the storage of [(18)F]-fluorodopamine within synaptic vesicles, mainly of dopamine fibres. As such, FDOPA PET is a sensitive indicator of the integrity of the nigrostriatal dopamine innervation. Nonetheless, there have been several reports of focal elevations of FDOPA utilization in brain of patients with Parkinson's disease (PD), all based on reference tissue methods. To investigate this phenomenon further, we used voxel-wise steady-state kinetic analysis to search for regions of elevated FDOPA utilization (K; ml g(-1) min(-1)) and steady-state trapping (V(d); ml g(-1)) in a group of well-characterized patients with early, asymmetric PD, who were contrasted with an age-matched control group. Subtraction of the population mean parametric maps revealed foci of increased FDOPA utilization K (+25%) in the bilateral medial nucleus accumbens, whereas the expected declines in the trapping of FDOPA were seen in the caudate and putamen. This observation suggests hyperfunction of catecholamine fibres innervating specifically the limbic striatum, which could guide the design of future prospective FDOPA-PET studies of the impulse control disorders occurring in some PD patients under treatment with dopamine agonists. A focus of increased FDOPA influx and also V(d) was detected in the periaqueductal grey, consistent with some earlier reports based on reference tissue analysis. Increased FDOPA trapping in the periaqueductal grey of PD patients seems consistent with recent reports of increased activity of serotonin neurons in a rat model of parkinsonism.
Collapse
|
28
|
Domino EF, Tsukada H, Harada N. Positron emission tomographic measure of brain dopamine dependence to nicotine as a model of drugs of abuse. Psychopharmacology (Berl) 2009; 204:149-53. [PMID: 19137279 DOI: 10.1007/s00213-008-1445-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Accepted: 12/17/2008] [Indexed: 11/27/2022]
Abstract
RATIONALE Nicotine/tobacco are prototypic substances used throughout the world. Nicotine abstinence produces some depressive-like effects which are treated by the dopamine (DA) and norepinephrine reuptake inhibitor bupropion. A quantitative measure of the regional brain utilization of these catecholamines (CA) during nicotine dependence and withdrawal is important. OBJECTIVE The aim of this study was to prove that regional brain DA utilization by nicotine can be quantified by positron emission tomography (PET) using L-[beta-(11)C]DOPA. MATERIALS AND METHODS Eight young Macaca mulatta monkeys were given 0.9% NaCl or nicotine in doses of 32 or 100 microg/kg i.m. bid for 9 days to produce minimal dependence. On the tenth day, PET measurements were repeated before and after i.v. nicotine administration. PET studies were done in habituated, trained, and fully conscious animals. RESULTS Compared to a 0.9% NaCl control, acute i.v. nicotine as a bolus plus infusion for 30 min in similar doses to maintain a steady-state level for 30 min did not affect the utilization rate constant (k (3)) in dorsal or ventral striatum as measured by L-[beta-(11)C]DOPA. When monkeys were given nicotine bid repeatedly after overnight nicotine abstinence, CA utilization was reduced. A subsequent nicotine dose normalized utilization to slightly above control levels. Changes in ventral striatum were similar to those in dorsal striatum. The reduced rate of utilization demonstrated with L-[beta-(11)C]DOPA after overnight nicotine abstinence and its reversal by nicotine the next day provides an important PET measure of brain nicotine dependence and withdrawal. This method can be applied to other substances of abuse that release DA.
Collapse
Affiliation(s)
- Edward F Domino
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109-0632, USA.
| | | | | |
Collapse
|
29
|
Urdinguio RG, Lopez-Serra L, Lopez-Nieva P, Alaminos M, Diaz-Uriarte R, Fernandez AF, Esteller M. Mecp2-null mice provide new neuronal targets for Rett syndrome. PLoS One 2008; 3:e3669. [PMID: 18989361 PMCID: PMC2576441 DOI: 10.1371/journal.pone.0003669] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Accepted: 10/21/2008] [Indexed: 12/27/2022] Open
Abstract
Background Rett syndrome (RTT) is a complex neurological disorder that is one of the most frequent causes of mental retardation in women. A great landmark in research in this field was the discovery of a relationship between the disease and the presence of mutations in the gene that codes for the methyl-CpG binding protein 2 (MeCP2). Currently, MeCP2 is thought to act as a transcriptional repressor that couples DNA methylation and transcriptional silencing. The present study aimed to identify new target genes regulated by Mecp2 in a mouse model of RTT. Methodology/Principal Findings We have compared the gene expression profiles of wild type (WT) and Mecp2-null (KO) mice in three regions of the brain (cortex, midbrain, and cerebellum) by using cDNA microarrays. The results obtained were confirmed by quantitative real-time PCR. Subsequent chromatin immunoprecipitation assays revealed seven direct target genes of Mecp2 bound in vivo (Fkbp5, Mobp, Plagl1, Ddc, Mllt2h, Eya2, and S100a9), and three overexpressed genes due to an indirect effect of a lack of Mecp2 (Irak1, Prodh and Dlk1). The regions bound by Mecp2 were always methylated, suggesting the involvement of the methyl-CpG binding domain of the protein in the mechanism of interaction. Conclusions We identified new genes that are overexpressed in Mecp2-KO mice and are excellent candidate genes for involvement in various features of the neurological disease. Our results demonstrate new targets of MeCP2 and provide us with a better understanding of the underlying mechanisms of RTT.
Collapse
Affiliation(s)
- Rocio G. Urdinguio
- Cancer Epigenetics Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Lidia Lopez-Serra
- Cancer Epigenetics Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Pilar Lopez-Nieva
- Cancer Epigenetics Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Miguel Alaminos
- Cancer Epigenetics Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Ramon Diaz-Uriarte
- Statistical Computing Team, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Agustin F. Fernandez
- Cancer Epigenetics Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Manel Esteller
- Cancer Epigenetics Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
- Cancer Epigenetics and Biology Program (PEBC), Catalan Institute of Oncology (ICO) and Institut d'Investigacio Biomedica de Bellvitge (IDIBELL), Barcelona, Catalonia, Spain
- Institucio Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Catalonia, Spain
- * E-mail:
| |
Collapse
|
30
|
Nakao R, Okada M, Inoue O, Fukumura T, Suzuki K. Combining high-performance liquid chromatography-positron detection and on-line microdialysis for animal metabolism study of positron emission tomography probes. J Chromatogr A 2008; 1203:193-7. [DOI: 10.1016/j.chroma.2008.07.049] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 07/10/2008] [Accepted: 07/17/2008] [Indexed: 10/21/2022]
|
31
|
Kumakura Y, Vernaleken I, Buchholz HG, Borghammer P, Danielsen E, Gründer G, Heinz A, Bartenstein P, Cumming P. Age-dependent decline of steady state dopamine storage capacity of human brain: an FDOPA PET study. Neurobiol Aging 2008; 31:447-63. [PMID: 18541344 DOI: 10.1016/j.neurobiolaging.2008.05.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2008] [Revised: 04/23/2008] [Accepted: 05/01/2008] [Indexed: 01/17/2023]
Abstract
Conventional indices of the utilization of FDOPA in living human brain have not consistently revealed important declines in dopamine function with normal aging. However, most methods of kinetic analysis have assumed irreversible trapping of decarboxylated FDOPA metabolites in brain, an assumption that is violated even in PET recordings of short duration. Therefore, we have developed methods for the calculation of steady-state storage of FDOPA together with its decarboxylated metabolites (V(d), mlg(-1)), based upon improved kinetic analysis of 120-min emission recordings. In a group of 28 normal male subjects, of age ranging from 23 to 73 years, the magnitude of V(d) in the striatum and in extrastriatal regions declined by approximately 10% with each decade. The utilization of FDOPA was also calculated by several conventional methods assuming irreversible trapping, i.e. the net blood brain clearance (K(in)(app), mlg(-1)min(-1)), the DOPA decarboxylase activity relative to a reference tissue input (k(3)(S), min(-1)), and relative to the arterial input (k(3)(D), min(-1)). None of these methods revealed an age-related decline in FDOPA utilization in the extended striatum, although the magnitude of K(in)(app) did decline in cerebral cortex. Thus, the capacity to synthesize [(18)F]fluorodopamine remained largely intact in striatum of the elderly subjects, but in the presence of a substantially increased rate of washout (k(loss)), which was evident in all brain regions examined. Consequently, the magnitude of V(d) declined with healthy aging, possibly reflecting impaired vesicular storage capacity, resulting in enhanced exposure of cytosolic [(18)F]fluorodopamine to monoamine oxidase.
Collapse
Affiliation(s)
- Yoshitaka Kumakura
- Centre for Functionally Integrative Neuroscience, Aarhus University, Aarhus C. 8000, Denmark.
| | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Landvogt C, Mengel E, Bartenstein P, Buchholz HG, Schreckenberger M, Siessmeier T, Scheurich A, Feldmann R, Weglage J, Cumming P, Zepp F, Ullrich K. Reduced cerebral fluoro-L-dopamine uptake in adult patients suffering from phenylketonuria. J Cereb Blood Flow Metab 2008; 28:824-31. [PMID: 17971791 DOI: 10.1038/sj.jcbfm.9600571] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Deficiency of phenylalanine hydroxylase activity in phenylketonuria (PKU) causes an excess of phenylalanine (Phe) throughout the body, predicting impaired synthesis of catecholamines in the brain. To test this hypothesis, we used positron emission tomography (PET) to measure the utilization of 6-[18F]fluoro-L-DOPA [corrected] (FDOPA) in the brain of adult patients suffering from PKU and in healthy controls. Dynamic 2-h long FDOPA emission recordings were obtained in seven adult PKU patients (five females, two males; age: 21 to 27 years) with elevated serum Phe levels, but lacking neurologic deficits. Seven age-matched, healthy volunteers were imaged under identical conditions. The utilization of FDOPA in striatum was calculated by linear graphical analysis (k3S, min(-1)), with cerebellum serving as a nonbinding reference region. The time to peak activity in all brain time-radioactivity curves was substantially delayed in the PKU patients relative to the control group. The mean magnitude of k3S in the striatum of the PKU patients (0.0052+/-0.0004 min(-1)) was significantly lower than in the control group (0.0088+/-0.0009 min(-1)) (P<0.001). There was no significant correlation between individual serum Phe levels and k3S. The unidirectional clearance of FDOPA to brain was impaired in adult patients suffering from PKU, presumably reflecting the competitive inhibition of the large neutral amino acid carrier by Phe. Assuming this competition to be spatially uniform, the relationship between striatum and cerebellum time-activity curves additionally suggests inhibition of DOPA efflux, possibly also due to competition from Phe. The linear graphical analysis shows reduced k3S in striatum, indicating reduced DOPA decarboxylase activity.
Collapse
|
33
|
Ratio of dopamine synthesis capacity to D2 receptor availability in ventral striatum correlates with central processing of affective stimuli. Eur J Nucl Med Mol Imaging 2008; 35:1147-58. [PMID: 18202844 DOI: 10.1007/s00259-007-0683-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Accepted: 12/14/2007] [Indexed: 02/06/2023]
Abstract
PURPOSE Dopaminergic neurotransmission in the ventral striatum may interact with limbic processing of affective stimuli, whereas dorsal striatal dopaminergic neurotransmission can affect habitual processing of emotionally salient stimuli in the pre-frontal cortex. We investigated the dopaminergic neurotransmission in the ventral and dorsal striatum with respect to central processing of affective stimuli in healthy subjects. METHODS Subjects were investigated with positron emission tomography and [(18)F]DOPA for measurements of dopamine synthesis capacity and [(18)F]DMFP for estimation of dopamine D2 receptor binding potential. Functional magnetic resonance imaging was used to assess the blood-oxygen-level-dependent (BOLD) response to affective pictures, which was correlated with the ratio of [(18)F]DOPA net influx constant K(app)(in)/[(18)F]DMFP-binding potential (BP_ND) in the ventral and dorsal striatum. RESULTS The magnitude of the ratio in the ventral striatum was positively correlated with BOLD signal increases elicited by negative versus neutral pictures in the right medial frontal gyrus (BA10), right inferior parietal lobe and left post-central gyrus. In the dorsal striatum, the ratio was positively correlated with BOLD signal activation elicited by negative versus neutral stimuli in the left post-central gyrus. The BOLD signal elicited by positive versus neutral stimuli in the superior parietal gyrus was positively correlated with the dorsal and ventral striatal ratio. CONCLUSIONS The correlations of the ratio in the ventral and dorsal striatum with processing of affective stimuli in the named cortical regions support the hypothesis that dopamine transmission in functional divisions of the striatum modulates processing of affective stimuli in specific cortical areas.
Collapse
|
34
|
Vernaleken I, Kumakura Y, Buchholz HG, Siessmeier T, Hilgers RD, Bartenstein P, Cumming P, Gründer G. Baseline [18F]-FDOPA kinetics are predictive of haloperidol-induced changes in dopamine turnover and cognitive performance: A positron emission tomography study in healthy subjects. Neuroimage 2008; 40:1222-31. [PMID: 18262797 DOI: 10.1016/j.neuroimage.2007.12.045] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2007] [Revised: 12/23/2007] [Accepted: 12/28/2007] [Indexed: 10/22/2022] Open
Abstract
The telencephalic dopamine innervations contribute to the modulation of cognitive processing. However, the relationship between cognitive effects of D(2/3)-receptor antagonism and dopamine transmission is not described in healthy subjects. We therefore tested effects of acute haloperidol (5 mg/d over 3 days) on continuous performance task (CPT) performance and 6-[(18)F]-fluoro-l-DOPA (FDOPA) PET parameters. Nine physically and mentally healthy male men performed two FDOPA-PET scans including arterial plasma withdrawal. Over 3 days before the second scan, all subjects were treated with 5 mg/d haloperidol orally. Using our novel steady-state analysis, we calculated the intrinsic rate of the cerebral FDOPA utilization (K), the turnover of [(18)F]fluorodopamine formed in brain (k(loss)) and the storage for FDOPA and its brain metabolites (V(d)). Furthermore, a ds-CPT and EPS-screening was performed before every PET scan. We found that FDOPA kinetics in those normal subjects with relatively high baseline K showed a more pronounced sensitivity to haloperidol treatment, manifesting in reduced storage capacity and elevated turnover of [(18)F]fluorodopamine, whereas subjects with lower K showed the opposite pattern of responses. Furthermore, low baseline K predicted improvements in the CPT task after haloperidol, whereas participants with higher baseline K showed a decline in cognitive performance. We conclude that the initial increase of [(18)F]fluorodopamine turnover after acute haloperidol challenge is associated with an over-stimulation in individuals with initially more pharmacologically responsive dopamine systems, but optimizes cognitive performance in those with lower normal FDOPA utilization at baseline. We hypothesize that these effects may be driven by D(1)-receptor mediated transmission during D(2) blockade.
Collapse
Affiliation(s)
- Ingo Vernaleken
- Department of Psychiatry and Psychotherapy, RWTH Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
35
|
Ikoma Y, Watabe H, Shidahara M, Naganawa M, Kimura Y. PET kinetic analysis: error consideration of quantitative analysis in dynamic studies. Ann Nucl Med 2008; 22:1-11. [DOI: 10.1007/s12149-007-0083-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Accepted: 10/03/2007] [Indexed: 11/25/2022]
|
36
|
Vernaleken I, Buchholz HG, Kumakura Y, Siessmeier T, Stoeter P, Bartenstein P, Cumming P, Gründer G. 'Prefrontal' cognitive performance of healthy subjects positively correlates with cerebral FDOPA influx: an exploratory [18F]-fluoro-L-DOPA-PET investigation. Hum Brain Mapp 2007; 28:931-9. [PMID: 17133402 PMCID: PMC6871482 DOI: 10.1002/hbm.20325] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Dopamine neurotransmission influences those cognitive processes, which are generally regarded as prefrontal cortical functions. In previous positron-emission-tomography (PET) studies, net blood-brain clearance of [18F]-fluoro-l-DOPA (FDOPA) correlated with impaired cognitive performance in patients with Parkinson's disease or schizophrenia. We hypothesized that FDOPA influx also correlates with performance of cognitive tasks associated with prefrontal functioning in healthy volunteers. The net blood-brain clearance of FDOPA (K(in)(app)) was mapped in a group of 11 healthy volunteers and calculated in striatal volumes-of-interest. The Wisconsin-Card-Sorting-Test (WCST), Stroop-Test, Trail-Making-Test (TMT-A/B), and Continuous-Performance-Test (CPT-M) had been administered previously to the same subjects. No correlation of K(in) (app) with perseverative errors in WCST or age could be found. However, there were significant positive correlations between the magnitude of K(in)(app) in caudate nucleus, putamen, and midbrain with performance of the TMT-B, CPT-M, and the Stroop test. Highest correlations were found between the time needed to perform the Stroop interference task and the K(in)(app) of striatal areas (Caudate nucleus: -0.780, P = 0.005; putamen: -0.870, P < 0. 001). Thus, the present findings reveal a strong correlation between dopamine synthesis capacity in striatum of healthy volunteers and performance of cognitive tasks linked to the prefrontal cortex.
Collapse
Affiliation(s)
- Ingo Vernaleken
- Department of Psychiatry and Psychotherapy, RWTH Aachen University, Aachen, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
37
|
Ito H, Shidahara M, Takano H, Takahashi H, Nozaki S, Suhara T. Mapping of central dopamine synthesis in man, using positron emission tomography with L-[beta-11C]DOPA. Ann Nucl Med 2007; 21:355-60. [PMID: 17705016 DOI: 10.1007/s12149-007-0033-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Accepted: 04/05/2007] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To estimate the presynaptic function of the central dopaminergic system, positron emission tomography measurement of the endogenous dopamine synthesis rate was performed with L-[beta-11C]DOPA. In the present study, we developed a simple method for calculating an indicator of the dopamine synthesis rate with L-[beta-11C]DOPA on a voxel-by-voxel basis for parametric mapping. METHODS After intravenous injection of L-[beta-11C]DOPA, dynamic scanning was performed on ten healthy men for 89 min. The dopamine synthesis ratio was calculated on a voxel-by-voxel basis as the ratio of the area under the time-activity curves of brain regions to the reference brain region, that is, occipital cortex. The overall uptake rate constant as an indicator of dopamine synthesis was also calculated by kinetic and graphical analyses. RESULTS The dopamine synthesis ratio calculated by the present method was in good agreement with the indicators of dopamine synthesis calculated by kinetic and graphical analyses, although a systemic underestimation was observed, especially when the integration interval was set in the early phase of the scan duration. In particular, underestimations were prominent in brain regions with relatively lower influx rate constant K1. CONCLUSIONS By this method, regional dopamine synthesis could be estimated on a voxel-by-voxel basis. This method does not need an arterial input function and should prove to be useful for clinical research.
Collapse
Affiliation(s)
- Hiroshi Ito
- Clinical Neuroimaging Team, Molecular Neuroimaging Group, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Chiba 263-8555, Japan.
| | | | | | | | | | | |
Collapse
|
38
|
Kumakura Y, Cumming P, Vernaleken I, Buchholz HG, Siessmeier T, Heinz A, Kienast T, Bartenstein P, Gründer G. Elevated [18F]fluorodopamine turnover in brain of patients with schizophrenia: an [18F]fluorodopa/positron emission tomography study. J Neurosci 2007; 27:8080-7. [PMID: 17652599 PMCID: PMC6672729 DOI: 10.1523/jneurosci.0805-07.2007] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Previous positron emission tomography (PET) studies with levodopa analogs have revealed a modestly increased capacity for dopamine synthesis in the striatum of patients with schizophrenia compared with healthy age-matched control subjects. We hypothesized that not just the synthesis but also the turnover of radiolabeled dopamine is elevated in patients. To test the hypothesis, we reanalyzed 2-h-long [18F]fluorodopa (FDOPA)/PET recordings from eight unmedicated patients with schizophrenia and 15 healthy age-matched control subjects, using new methods for the quantification of [18F]fluorodopamine steady-state kinetics. The fractional rate constant for the catabolism and elimination of [18F]fluorodopamine was elevated nearly twofold in striatum, the largest biochemical difference in brain of schizophrenics yet reported. The magnitude of the intrinsic blood-brain FDOPA clearance with correction for this loss of [18F]fluorodopamine metabolites was increased by 20% in caudate and putamen and by 50% in amygdala and midbrain of the patients. However, the magnitude of the steady-state storage of FDOPA and its decarboxylated metabolites (V(d)) was reduced by one-third in the caudate nucleus and amygdala of the schizophrenic group. Thus, reduced steady-state storage of [18F]fluorodopamine occurs in the midst of accelerated synthesis in brain of untreated patients. Positive scores of the positive and negative syndrome scale correlated inversely with the magnitude of V(d) in amygdala, suggesting an association between positive symptoms and impaired steady-state storage of FDOPA metabolites in that structure.
Collapse
Affiliation(s)
- Yoshitaka Kumakura
- Centre for Functionally Integrative Neuroscience, Aarhus University, DK-8000 Aarhus C, Denmark.
| | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Popkov A, Blahutová A, Kaňová M. Can 6-[18F]fluoroDOPA be an accurate alternative for β-[11C]DOPA? J Labelled Comp Radiopharm 2007. [DOI: 10.1002/jlcr.1241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
|
40
|
Siessmeier T, Kienast T, Wrase J, Larsen JL, Braus DF, Smolka MN, Buchholz HG, Schreckenberger M, Rösch F, Cumming P, Mann K, Bartenstein P, Heinz A. Net influx of plasma 6-[18F]fluoro-L-DOPA (FDOPA) to the ventral striatum correlates with prefrontal processing of affective stimuli. Eur J Neurosci 2006; 24:305-13. [PMID: 16882026 DOI: 10.1111/j.1460-9568.2006.04903.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Dopaminergic neurotransmission in the ventral and dorsal striatum interact with central processing of rewarding and reward-indicating stimuli, and may affect frontocortical-striatal-thalamic circuits regulating goal-directed behaviour. Thirteen healthy male volunteers were investigated with multimodal imaging, using the radioligand 6-[(18)F]fluoro-l-DOPA (FDOPA) for positron emission tomography (PET) measurements of dopamine synthesis capacity, and also functional magnetic resonance imaging (fMRI) in a cognitive activation paradigm. We calculated the correlation between FDOPA net blood-brain influx (; ml/g/min) in the ventral and associative dorsal striatum and BOLD signal changes elicited by standardized affectively positive, negative and neutral visual stimuli. The magnitude of in the ventral striatum was positively correlated with BOLD signal increases in the left anterior cingulate cortex and right insular operculum elicited by positive vs. neutral stimuli, but not negative vs. neutral stimuli. In the dorsal striatum, the magnitude of was positively correlated with processing of positive and negative stimuli in the left dorsolateral prefrontal cortex. These findings suggest that dopamine synthesis capacity in the ventral striatum correlates with the attentional processing of rewarding positive stimuli in the anterior cingulate cortex of healthy subjects. Dopaminergic neurotransmission in the associative dorsal striatum has been associated previously with habit learning. The observed correlation between dopamine synthesis capacity in the dorsal striatum and BOLD signal changes in the dorsolateral prefrontal cortex suggests dopaminergic modulation of processing of emotional stimuli in brain areas associated with motor planning and executive behaviour control.
Collapse
|
41
|
Ito H, Ota M, Ikoma Y, Seki C, Yasuno F, Takano A, Maeda J, Nakao R, Suzuki K, Suhara T. Quantitative analysis of dopamine synthesis in human brain using positron emission tomography with L-[β-11C]DOPA. Nucl Med Commun 2006; 27:723-31. [PMID: 16894327 DOI: 10.1097/01.mnm.0000230069.08576.6d] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND OBJECTIVES To estimate the presynaptic function of the central dopaminergic system, the rate of endogenous dopamine synthesis has been measured by using L-[beta-C]DOPA or 6-[F]fluoro-L-DOPA with positron emission tomography. However, the regional kinetics of L-[beta-C]DOPA in human brain have not been investigated in detail. In the present study, the regional kinetics of L-[beta-C]DOPA in normal human brain and the accuracy of the method for quantifying L-[beta-C]DOPA kinetics, employing reference regions, were investigated. METHODS After intravenous injection of L-[beta-C]DOPA, dynamic scanning was performed on ten healthy subjects for 89 min. The overall uptake rate constant K was calculated by the kinetic and graphical approaches, in which the occipital cortex was used as a reference brain region. RESULTS Regional distribution of K was similar to those of dopamine D2 receptor. A significant negative correlation was observed between the neutral amino acid concentration in plasma and the influx rate constant through the blood-brain barrier (K1). The K values calculated by graphical approach were in good agreement with the values calculated by kinetic approach for both experimental and simulated data. CONCLUSIONS The regional distribution of K corresponds to that of the nigrostriatal and mesolimbic dopaminergic system. Negative correlation between neutral amino acid concentration and K1 supports the suggestion that L-DOPA is transported in a competitive fashion via the same carrier system as neutral amino acids at the blood-brain barrier. Because the graphical approach can obviate the need for an arterial input function, it is useful for investigating the rate of regional dopamine synthesis in neuropsychiatric and neurodegenerative diseases.
Collapse
Affiliation(s)
- Hiroshi Ito
- Departments of Molecular Neuroimaging, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Doudet DJ, Rosa-Neto P, Munk OL, Ruth TJ, Jivan S, Cumming P. Effect of age on markers for monoaminergic neurons of normal and MPTP-lesioned rhesus monkeys: A multi-tracer PET study. Neuroimage 2006; 30:26-35. [PMID: 16378735 DOI: 10.1016/j.neuroimage.2005.09.044] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2005] [Revised: 08/31/2005] [Accepted: 09/06/2005] [Indexed: 10/25/2022] Open
Abstract
The binding of three tracers for monoaminergic terminals was mapped in the brain of healthy young (N=6) and healthy old rhesus monkeys (N=4), aged monkeys with mild unilateral intracarotid MPTP lesions (N=3), and monkeys of intermediate age with severe systemic MPTP lesions (N=6). The ligand for monoaminergic vesicles (+)-[(11)C]dihydrotetrabenazine (+DTBZ) had a mean binding potential (pB) of 1.4 in striatum of the healthy young monkeys, which was reduced by 20% in putamen of the old monkeys. The catecholamine transporter ligand (+)-[(11)C]methylphenidate (+MP) had a mean pB of 1.3 in striatum of the young monkeys, which was reduced by 40% in caudate and putamen of the old monkeys. The DOPA decarboxylase substrate [(18)F]fluoro-l-DOPA (FDOPA) had a mean decarboxylation coefficient (k(3)(S)) of 0.4 h(-1) in striatum of the young group, and was not significantly reduced in the aged group. Of the three ligands, only +DTBZ pB was significantly reduced in striatum of the small group of animals with mild unilateral lesions. In the group with systemic MPTP lesions, the mean reduction of the binding of the three ligands was 80% in the caudate and putamen. However, the decline in +MP pB in the ventral striatum (-75%) exceeded the declines of +DTBZ pB and FDOPA k(3)(S) in that region (-65%), suggesting that compensatory down-modulation of uptake sites may occur in the striatal regions with the least dopamine depletion. Binding of all three ligands was reduced by 50% in the anterior cingulate cortex and in the thalamus, suggesting toxicity of MPTP for extrastriatal catecholamine innervations. +DTBZ binding in the hypothalamus, presumably mainly in serotonin fibers, was unaffected by systemic MPTP treatment. Of the three tracers, +DTBZ was most sensitive for detecting MPTP-induced dopamine depletion in monkey striatum.
Collapse
Affiliation(s)
- Doris J Doudet
- Department Medicine/Neurology and UBC/TRIUMFPET Program, University of British Columbia, Vancouver, Canada
| | | | | | | | | | | |
Collapse
|
43
|
Kumakura Y, Gjedde A, Danielsen EH, Christensen S, Cumming P. Dopamine storage capacity in caudate and putamen of patients with early Parkinson's disease: correlation with asymmetry of motor symptoms. J Cereb Blood Flow Metab 2006; 26:358-70. [PMID: 16079784 DOI: 10.1038/sj.jcbfm.9600202] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Conventional graphical analysis of positron emission tomography (PET) recordings of the cerebral uptake of the DOPA decarboxylase substrate [(18)F]fluorodopa (FDOPA) assumes irreversible trapping of [(18)F]fluorodopamine formed in the brain. However, 4-h long PET recordings allow the estimation of a rate constant for elimination of [(18)F]fluorodopamine from the brain (k(loss)), from which can be calculated an effective distribution volume (EDV(1)), which is an index of [(18)F]fluorodopamine storage capacity. We earlier developed a method employing 2-h long FDOPA recordings for the estimation of k(loss) and EDV, here defined as EDV(2). This method is based on subtraction of the calculated brain concentrations of the FDOPA metabolite O-methyl-FDOPA, rather than the subtraction of the entire radioactivity in a reference region. We now extend this method for the parametric mapping of these parameters in the brain of healthy aged volunteers and patients with Parkinson's disease (PD), with asymmetry of motor symptoms. For parametric mapping, we use a novel application of a multilinear solution for the two-tissue compartment FDOPA model. We also test a new application of the Logan graphical analysis for mapping of the FDOPA distribution volume at equilibrium. The estimates of k(loss) and EDV(2) were more sensitive for the discrimination of biochemical abnormality in the putamen of patients with early PD relative to healthy aged subjects, than was the conventional net influx estimate. Of the several methods, multilinear estimates of EDV(2) were most sensitive for discrimination of PD and normal putamen. However, k(loss) was most sensitive for detecting biochemical asymmetry in the putamen of PD patients, and only k(loss) also detected in the caudate of PD patients a decline in the retention of [(18)F]fluorodopamine relative to healthy aged control subjects.
Collapse
|
44
|
Vernaleken I, Kumakura Y, Cumming P, Buchholz HG, Siessmeier T, Stoeter P, Müller MJ, Bartenstein P, Gründer G. Modulation of [18F]fluorodopa (FDOPA) kinetics in the brain of healthy volunteers after acute haloperidol challenge. Neuroimage 2006; 30:1332-9. [PMID: 16439159 DOI: 10.1016/j.neuroimage.2005.11.014] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2005] [Revised: 11/03/2005] [Accepted: 11/09/2005] [Indexed: 11/23/2022] Open
Abstract
In animal studies, acute antipsychotic treatment was shown to enhance striatal DOPA-decarboxylase (DDC) activity. However, this phenomenon has not been demonstrated in humans by positron emission tomography (PET). Therefore, we investigated acute haloperidol effects on DDC activity in humans using [18F]fluorodopa (FDOPA) PET. Nine healthy volunteers were scanned with FDOPA in drug-free baseline conditions and after 3 days of haloperidol treatment (5 mg/day). A continuous performance test (CPT) was administered in both conditions. The net blood-brain clearance of FDOPA (K(in)app) in striatum, mesencephalon, and medial prefrontal cortex was calculated by volume-of-interest analysis. The macroparameter K(in)app is a composite of several kinetic terms defining the distribution volume of FDOPA in brain (V(e)D) and the relative activity of DOPA decarboxylase (k3D). Therefore, compartmental kinetic analysis was used to identify the physiological basis of the observed changes in K(in)app period. The magnitude of K(in)app was significantly increased in the putamen (18%) and mesencephalon (36%). Furthermore, V(e)D in the brain was increased by 15%. Increments of k3(D) in the basal ganglia did not attain statistical significance. The significant worsening of CPT results did not correlate with changes in FDOPA utilization. The present PET results indicate potentiation of FDOPA utilization in human basal ganglia by acute haloperidol treatment, apparently due to increased availability throughout the brain. The stimulation of DDC cannot be excluded due to insufficient statistical power in the estimation of k3(D) changes.
Collapse
Affiliation(s)
- Ingo Vernaleken
- Department of Psychiatry and Psychotherapy, RWTH Aachen University, Aachen, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Kumakura Y, Vernaleken I, Gründer G, Bartenstein P, Gjedde A, Cumming P. PET studies of net blood-brain clearance of FDOPA to human brain: age-dependent decline of [18F]fluorodopamine storage capacity. J Cereb Blood Flow Metab 2005; 25:807-19. [PMID: 15729292 DOI: 10.1038/sj.jcbfm.9600079] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Conventional methods for the graphical analysis of 6-[(18)F]fluorodopa (FDOPA)/positron emission tomography (PET) recordings (K(in)(app)) may be prone to negative bias because of oversubtraction of the precursor pool in the region of interest, and because of diffusion of decarboxylated FDOPA metabolites from the brain. These effects may reduce the sensitivity of FDOPA/PET for the detection of age-related changes in dopamine innervations. To test for these biasing effects, we have used a constrained compartmental analysis to calculate the brain concentrations of the plasma metabolite 3-O-methyl-FDOPA (OMFD) during 120 mins of FDOPA circulation in healthy young, healthy elderly, and Parkinson's disease subjects. Calculated brain OMFD concentrations were subtracted frame-by-frame from the dynamic PET recordings, and maps of the FDOPA net influx to brain were calculated assuming irreversible trapping (K(app)). Comparison of K(in)(app) and K(app) maps revealed a global negative bias in the conventional estimates of FDOPA clearance. The present OMFD subtraction method revealed curvature in plots of K(app) at early times, making possible the calculation of the corrected net influx (K) and also the rate constant for diffusion of decarboxylated metabolites from the brain (k(loss)). The effective distribution volume (EDV(2); K/k(loss)) for FDOPA, an index of dopamine storage capacity in brain, was reduced by 85% in putamen of patients with Parkinson's disease, and by 58% in the healthy elderly relative to the healthy young control subjects. Results of the present study support claims that storage capacity for dopamine in both caudate and putamen is more profoundly impaired in patients with Parkinson's disease than is the capacity for DOPA utilization, calculated by conventional FDOPA net influx plots. The present results furthermore constitute the first demonstration of an abnormality in the cerebral utilization of FDOPA in caudate and putamen as a function of normal aging, which we attribute to loss of vesicular storage capacity.
Collapse
|
46
|
Andersen F, Watanabe H, Bjarkam C, Danielsen EH, Cumming P. Pig brain stereotaxic standard space: Mapping of cerebral blood flow normative values and effect of MPTP-lesioning. Brain Res Bull 2005; 66:17-29. [PMID: 15925140 DOI: 10.1016/j.brainresbull.2005.02.033] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2004] [Revised: 02/23/2005] [Accepted: 02/25/2005] [Indexed: 10/25/2022]
Abstract
The analysis of physiological processes in brain by position emission tomography (PET) is facilitated when images are spatially normalized to a standard coordinate system. Thus, PET activation studies of human brain frequently employ the common stereotaxic coordinates of Talairach. We have developed an analogous stereotaxic coordinate system for the brain of the Gottingen miniature pig, based on automatic co-registration of magnetic resonance (MR) images obtained in 22 male pigs. The origin of the pig brain stereotaxic space (0, 0, 0) was arbitrarily placed in the centroid of the pineal gland as identified on the average MRI template. The orthogonal planes were imposed using the line between stereotaxic zero and the optic chiasm. A series of mean MR images in the coronal, sagittal and horizontal planes were generated. To test the utility of the common coordinate system for functional imaging studies of minipig brain, we calculated cerebral blood flow (CBF) maps from normal minipigs and from minipigs with a syndrome of parkisonism induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-poisoning. These maps were transformed from the native space into the common stereotaxic space. After global normalization of these maps, an undirected search for differences between the groups was then performed using statistical parametric mapping. Using this method, we detected a statistically significant focal increase in CBF in the left cerebellum of the MPTP-lesioned group. We expect the present approach to be of general use in the statistical parametric mapping of CBF and other physiological parameters in living pig brain.
Collapse
Affiliation(s)
- Flemming Andersen
- PET Center, Aarhus University Hospitals, and Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark.
| | | | | | | | | |
Collapse
|
47
|
Laakso A, Pohjalainen T, Bergman J, Kajander J, Haaparanta M, Solin O, Syvälahti E, Hietala J. The A1 allele of the human D2 dopamine receptor gene is associated with increased activity of striatal L-amino acid decarboxylase in healthy subjects. Pharmacogenet Genomics 2005; 15:387-91. [PMID: 15900211 DOI: 10.1097/01213011-200506000-00003] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The A1 allele of the TaqI restriction fragment length polymorphism (RFLP) of the human dopamine D2 receptor gene (DRD2) is associated with a low density of D2 dopamine receptors in the striatum. Because of the important role of D2 autoreceptors in regulating dopamine synthesis, we aimed to examine whether subjects with the A1 allele have altered presynaptic dopamine function in the brain. We also studied the effects of two other DRD2 polymorphisms, C957 T and--141C Ins/Del, which have been suggested to affect D2 receptor levels in brain. The relationships between the TaqIA RFLP, C957 T and--141C Ins/Del polymorphisms and striatal dopamine synthesis in 33 healthy Finnish volunteers were studied using positron emission tomography and [18F]fluorodopa ([18F]FDOPA), a radiolabelled analog of the dopamine precursor L-DOPA. Heterozygous carriers of the A1 allele (A1/A2; 10 subjects) had significantly higher (18%) [18F]FDOPA uptake in the putamen than subjects without the A1 allele (A2/A2; 23 subjects). C957 T and--141C Ins/Del polymorphisms did not significantly affect [18F]FDOPA Ki values. These results demonstrate that the A1 allele of DRD2 gene is associated with increased striatal activity of aromatic L-amino acid decarboxylase, the final enzyme in the biosynthesis of dopamine and the rate-limiting enzyme for trace amine (e.g. beta-phenylethylamine) synthesis. The finding can be explained by lower D2 receptor expression leading to decreased autoreceptor function, and suggests that dopamine and/or trace amine synthesis rate is increased in the brains of A1 allele carriers.
Collapse
Affiliation(s)
- Aki Laakso
- Department of Pharmacology and Clinical Pharmacology, University of Turku, Turku University Central Hospital, Turku, Finland
| | | | | | | | | | | | | | | |
Collapse
|
48
|
Hassoun W, Thobois S, Ginovart N, Garcia-Larrea L, Cavorsin ML, Guillouet S, Bonnefoi F, Costes N, Lavenne F, Martin JP, Broussolle E, Leviel V. Striatal dopamine during sensorial stimulations: a [18F]FDOPA PET study in human and cats. Neurosci Lett 2005; 383:63-7. [PMID: 15936513 DOI: 10.1016/j.neulet.2005.03.067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2004] [Revised: 02/25/2005] [Accepted: 03/28/2005] [Indexed: 11/29/2022]
Abstract
Sensory stimulations of the forelimb in cats are known to increase dopamine release in the ipsilateral striatum and to decrease it in the homologous contralateral structure. Using positron emission tomography in both humans and cats, the present study shows that such sensory stimulations greatly reduce [(18)F]FDOPA accumulation ipsilateral to the stimulation (by 40.4% and 26.4% in the human caudate and putamen, respectively, and by 33.3% in the cat striatum). This decrease in striatal [(18)F]FDOPA uptake suggests a reduced DA storage resulting from the increased amine release. No change was observed in the contralateral striatum in neither human or cat suggesting, in contrast, that [(18)F]FDOPA accumulation is not facilitated by decreased DA release. These results support the hypothesis that sensory stimulations activate a non-synaptic mode of dopamine release.
Collapse
Affiliation(s)
- Wadad Hassoun
- Physiologie Integrative Cellulaire et Moléculaire, CNRS UMR5123, Villeurbanne, France
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Bauer R, Walter B, Vorwieger G, Fritz A, Füchtner F, Zwiener U, Brust P. Effect of moderate hypercapnic hypoxia on cerebral dopaminergic activity and brain O2 uptake in intrauterine growth-restricted newborn piglets. Pediatr Res 2005; 57:363-70. [PMID: 15611347 DOI: 10.1203/01.pdr.0000150800.19956.f0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
There is evidence that intrauterine growth restriction (IUGR) is associated with altered dopaminergic function in the immature brain. Compelling evidence exists that in the newborn brain, specific structures are especially vulnerable to O2 deprivation. The dopaminergic system is shown to be sensitive to O2 deprivation in the immature brain. However, the respective enzyme activities have not been measured in the living neonatal brain after IUGR under hypercapnic hypoxia (H/H). Therefore, 18F-labeled 6-fluoro-L-3,4-dihydroxyphenylalanine (FDOPA) together with positron emission tomography was used to estimate the aromatic amino acid decarboxylase activity of the brain of seven normal weight (body weight 2078 +/- 434 g) and seven IUGR newborn piglets (body weight 893 +/- 109 g). Two positron emission tomography scans were performed in each piglet. All animals underwent a period of normoxia and moderate H/H. Simultaneously, cerebral blood flow was measured with colored microspheres and cerebral metabolic rate of O2 was determined. In newborn normal-weight piglets, the rate constant for FDOPA decarboxylation was markedly increased in mesostriatal regions during H/H, whereas brain oxidative metabolism remained unaltered. In contrast, moderate H/H induced in IUGR piglets a marked reduction of clearance rates for FDOPA metabolites (p <0.05), which was accompanied by a tendency of lowering the rate constant for FDOPA conversion. Furthermore, IUGR piglets maintained cerebral O2 uptake in the early period of H/H, but during the late period of H/H, a significantly reduced cerebral metabolic rate of O2 occurred (p <0.05). Thus, IUGR is accompanied by a missing activation of dopaminergic activity and attenuated brain oxidative metabolism during moderate H/H. This may indicate endogenous brain protection against O2 deprivation.
Collapse
Affiliation(s)
- Reinhard Bauer
- Institute of Pathophysiology and Pathobiochemistry, Universitätsklinikum Jena, Friedrich Schiller University, D-07740 Jena, Germany.
| | | | | | | | | | | | | |
Collapse
|
50
|
Kumakura Y, Danielsen EH, Reilhac A, Gjedde A, Cumming P. Levodopa effect on [18F]fluorodopa influx to brain: normal volunteers and patients with Parkinson's disease. Acta Neurol Scand 2004; 110:188-95. [PMID: 15285777 DOI: 10.1111/j.1600-0404.2004.00299.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Levodopa is the immediate precursor of dopamine and the substrate for DOPA decarboxylase, an enzyme subject to regulation in living brain. To test whether this regulation changes in disease, we used Positron Emission Tomography (PET) with parametric mapping to measure the effect of levodopa on the net clearance of [(18)F]fluorodopa to brain (K, ml/g/min). METHODS Five patients with early Parkinson's disease with pause of medication for 3 days and six age-matched healthy volunteers were studied in a baseline condition and after levodopa challenge. RESULTS Levodopa (200 mg as Sinemet) increased the magnitude of the net clearance K in the left and right putamen of the healthy volunteers by 11% relative to the baseline condition. In contrast, resumption of medication with levodopa did not significantly alter the magnitude of K in putamen of the Parkinson's disease patients. Compartmental analysis was used to probe the physiological basis of the activation of K: levodopa treatment increased by 15% the apparent distribution volume of [(18)F]fluorodopa in cerebellum (, ml/g) of both patients and control subjects, without significantly altering the unidirectional blood-brain clearance (, ml/g/min) or the relative activity of DOPA decarboxylase (, min(-1)) in putamen. CONCLUSION We conclude that levodopa treatment increases the distribution volume of [(18)F]fluorodopa in brain, increasing its availability for utilization in dopamine terminals. We speculate that levodopa act as a direct beta-adrenergic agonist at receptors regulating the permeability of the blood-brain barrier to levodopa. However, the PET analytical method was without sufficient power to detect the consequent increase in magnitude of K in brain of only five Parkinson's disease subjects.
Collapse
Affiliation(s)
- Y Kumakura
- PET Centre, Aarhus University Hospitals and Centre for Functionally Integrated Neuroscience, Aarhus, Denmark
| | | | | | | | | |
Collapse
|