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Wakeford AGP, Nye JA, Morin EL, Mun J, Meyer JS, Goodman M, Howell LL, Sanchez MM. Alterations in adolescent brain serotonin (5HT) 1A, 5HT 2A, and dopamine (D) 2 receptor systems in a nonhuman primate model of early life adversity. Neuropsychopharmacology 2024; 49:1227-1235. [PMID: 38671147 DOI: 10.1038/s41386-023-01784-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 10/30/2023] [Accepted: 12/04/2023] [Indexed: 04/28/2024]
Abstract
Stress affects brain serotonin (5HT) and dopamine (DA) function, and the effectiveness of 5HT and DA to regulate stress and emotional responses. However, our understanding of the long-term impact of early life adversity (ELA) on primate brain monoaminergic systems during adolescence is scarce and inconsistent. Filling this gap in the literature is critical, given that the emergence of psychopathology during adolescence has been related to deficits in these systems. Here, we use a translational nonhuman primate (NHP) model of ELA (infant maltreatment by the mother) to examine the long-term impact of ELA on adolescent 5HT1A, 5HT2A and D2 receptor systems. These receptor systems were chosen based on their involvement in stress/emotional control, as well as reward and reinforcement. Rates of maternal abuse, rejection, and infant's vocalizations were obtained during the first three postnatal months, and hair cortisol concentrations obtained at 6 months postnatal were examined as early predictors of binding potential (BP) values obtained during adolescence using positron emission tomography (PET) imaging. Maltreated animals demonstrated significantly lower 5HT1A receptor BP in prefrontal cortical areas as well as the amygdala and hippocampus, and lower 5HT2A receptor BP in striatal and prefrontal cortical areas. Maltreated animals also demonstrated significantly lower D2 BP in the amygdala. None of the behavioral and neuroendocrine measurements obtained early in life predicted any changes in BP data. Our findings suggest that early caregiving experiences regulate the development of brain 5HT and DA systems in primates, resulting in long-term effects evident during adolescence.
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Affiliation(s)
- Alison G P Wakeford
- Division of Neuropharmacology and Neurologic Diseases, Emory National Primate Research Center, Emory University, 954 Gatewood Rd NE, Atlanta, GA, 30329, USA
- Department of Psychiatry & Behavioral Sciences, Emory University, 12 Executive Park Dr NE #200, Atlanta, GA, 30329, USA
| | - Jonathon A Nye
- Department of Radiology and Imaging Sciences, Emory University, 1364 Clifton Rd. NE, Atlanta, GA, 30329, USA
| | - Elyse L Morin
- Department of Psychiatry & Behavioral Sciences, Emory University, 12 Executive Park Dr NE #200, Atlanta, GA, 30329, USA
- Division of Developmental and Cognitive Neuroscience, Emory National Primate Research Center, Emory University, 954 Gatewood Rd NE, Atlanta, GA, 30329, USA
| | - Jiyoung Mun
- Department of Radiology and Imaging Sciences, Emory University, 1364 Clifton Rd. NE, Atlanta, GA, 30329, USA
| | - Jerrold S Meyer
- Department of Psychological & Brain Sciences, University of Massachusetts, 441 Tobin Hall, Amherst, MA, 01003, USA
| | - Mark Goodman
- Department of Radiology and Imaging Sciences, Emory University, 1364 Clifton Rd. NE, Atlanta, GA, 30329, USA
| | - Leonard L Howell
- Division of Neuropharmacology and Neurologic Diseases, Emory National Primate Research Center, Emory University, 954 Gatewood Rd NE, Atlanta, GA, 30329, USA
- Department of Psychiatry & Behavioral Sciences, Emory University, 12 Executive Park Dr NE #200, Atlanta, GA, 30329, USA
| | - Mar M Sanchez
- Department of Psychiatry & Behavioral Sciences, Emory University, 12 Executive Park Dr NE #200, Atlanta, GA, 30329, USA.
- Division of Developmental and Cognitive Neuroscience, Emory National Primate Research Center, Emory University, 954 Gatewood Rd NE, Atlanta, GA, 30329, USA.
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Krysiak R, Kowalcze K, Szkróbka W, Okopień B. Impaired Prolactin-Lowering Effects of Metformin in Women with Polycystic Ovary Syndrome. J Clin Med 2023; 12:5474. [PMID: 37685540 PMCID: PMC10488133 DOI: 10.3390/jcm12175474] [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: 05/15/2023] [Revised: 08/21/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023] Open
Abstract
The effect of metformin on prolactin concentration seems to be sex-dependent. The aim of this study was to determine whether the androgen status modulates the impact of metformin on plasma prolactin levels in women. This study included two matched groups of prediabetic women with hyperprolactinemia: 25 with PCOS and 25 control subjects with androgen levels within the reference range and with normal ovarian morphology. Glucose homeostasis markers, prolactin, the remaining anterior pituitary hormones, sex hormones, SHBG and IGF-1 were determined before and after six months of metformin treatment. At baseline, both groups differed in LH, LH/FSH ratio, testosterone, FAI, DHEA-S, androstenedione and estradiol. Although metformin improved insulin sensitivity and increased SHBG in both study groups, these effects were more pronounced in control subjects than in women with PCOS. In control subjects, the drug decreased total and monomeric prolactin and increased LH. In women with PCOS, metformin reduced LH, LH/FSH ratio, testosterone and FAI. In the control group, the impact on total and monomeric prolactin positively correlated with their baseline levels and with the degree of improvement in insulin sensitivity, as well as negatively correlated with testosterone and FAI. In women with PCOS, treatment-induced changes in testosterone and FAI positively correlated with the changes in LH and LH/FSH ratio. The obtained results suggest that the prolactin-lowering properties of metformin are less pronounced in women with coexisting PCOS than in women with elevated prolactin levels, probably owing to the increased production of endogenous testosterone.
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Affiliation(s)
- Robert Krysiak
- Department of Internal Medicine and Clinical Pharmacology, Medical University of Silesia, Medyków 18, 40-752 Katowice, Poland; (W.S.); (B.O.)
| | - Karolina Kowalcze
- Department of Pediatrics in Bytom, Faculty of Health Sciences in Katowice, Medical University of Silesia, Stefana Batorego 15, 41-902 Bytom, Poland;
| | - Witold Szkróbka
- Department of Internal Medicine and Clinical Pharmacology, Medical University of Silesia, Medyków 18, 40-752 Katowice, Poland; (W.S.); (B.O.)
| | - Bogusław Okopień
- Department of Internal Medicine and Clinical Pharmacology, Medical University of Silesia, Medyków 18, 40-752 Katowice, Poland; (W.S.); (B.O.)
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Klink PC, Aubry JF, Ferrera VP, Fox AS, Froudist-Walsh S, Jarraya B, Konofagou EE, Krauzlis RJ, Messinger A, Mitchell AS, Ortiz-Rios M, Oya H, Roberts AC, Roe AW, Rushworth MFS, Sallet J, Schmid MC, Schroeder CE, Tasserie J, Tsao DY, Uhrig L, Vanduffel W, Wilke M, Kagan I, Petkov CI. Combining brain perturbation and neuroimaging in non-human primates. Neuroimage 2021; 235:118017. [PMID: 33794355 PMCID: PMC11178240 DOI: 10.1016/j.neuroimage.2021.118017] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 03/07/2021] [Accepted: 03/22/2021] [Indexed: 12/11/2022] Open
Abstract
Brain perturbation studies allow detailed causal inferences of behavioral and neural processes. Because the combination of brain perturbation methods and neural measurement techniques is inherently challenging, research in humans has predominantly focused on non-invasive, indirect brain perturbations, or neurological lesion studies. Non-human primates have been indispensable as a neurobiological system that is highly similar to humans while simultaneously being more experimentally tractable, allowing visualization of the functional and structural impact of systematic brain perturbation. This review considers the state of the art in non-human primate brain perturbation with a focus on approaches that can be combined with neuroimaging. We consider both non-reversible (lesions) and reversible or temporary perturbations such as electrical, pharmacological, optical, optogenetic, chemogenetic, pathway-selective, and ultrasound based interference methods. Method-specific considerations from the research and development community are offered to facilitate research in this field and support further innovations. We conclude by identifying novel avenues for further research and innovation and by highlighting the clinical translational potential of the methods.
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Affiliation(s)
- P Christiaan Klink
- Department of Vision & Cognition, Netherlands Institute for Neuroscience, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands.
| | - Jean-François Aubry
- Physics for Medicine Paris, Inserm U1273, CNRS UMR 8063, ESPCI Paris, PSL University, Paris, France
| | - Vincent P Ferrera
- Department of Neuroscience & Department of Psychiatry, Columbia University Medical Center, New York, NY, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Andrew S Fox
- Department of Psychology & California National Primate Research Center, University of California, Davis, CA, USA
| | | | - Béchir Jarraya
- NeuroSpin, Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Institut National de la Santé et de la Recherche Médicale (INSERM), Cognitive Neuroimaging Unit, Université Paris-Saclay, France; Foch Hospital, UVSQ, Suresnes, France
| | - Elisa E Konofagou
- Ultrasound and Elasticity Imaging Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY, USA; Department of Radiology, Columbia University, New York, NY, USA
| | - Richard J Krauzlis
- Laboratory of Sensorimotor Research, National Eye Institute, Bethesda, MD, USA
| | - Adam Messinger
- Laboratory of Brain and Cognition, National Institute of Mental Health, Bethesda, MD, USA
| | - Anna S Mitchell
- Department of Experimental Psychology, Oxford University, Oxford, United Kingdom
| | - Michael Ortiz-Rios
- Newcastle University Medical School, Newcastle upon Tyne NE1 7RU, United Kingdom; German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, 37077 Göttingen, Germany
| | - Hiroyuki Oya
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA, USA; Department of Neurosurgery, University of Iowa, Iowa city, IA, USA
| | - Angela C Roberts
- Department of Physiology, Development and Neuroscience, Cambridge University, Cambridge, United Kingdom
| | - Anna Wang Roe
- Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou 310029, China
| | | | - Jérôme Sallet
- Department of Experimental Psychology, Oxford University, Oxford, United Kingdom; Univ Lyon, Université Lyon 1, Inserm, Stem Cell and Brain Research Institute, U1208 Bron, France; Wellcome Centre for Integrative Neuroimaging, Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
| | - Michael Christoph Schmid
- Newcastle University Medical School, Newcastle upon Tyne NE1 7RU, United Kingdom; Faculty of Science and Medicine, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland
| | - Charles E Schroeder
- Nathan Kline Institute, Orangeburg, NY, USA; Columbia University, New York, NY, USA
| | - Jordy Tasserie
- NeuroSpin, Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Institut National de la Santé et de la Recherche Médicale (INSERM), Cognitive Neuroimaging Unit, Université Paris-Saclay, France
| | - Doris Y Tsao
- Division of Biology and Biological Engineering, Tianqiao and Chrissy Chen Institute for Neuroscience; Howard Hughes Medical Institute; Computation and Neural Systems, Caltech, Pasadena, CA, USA
| | - Lynn Uhrig
- NeuroSpin, Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Institut National de la Santé et de la Recherche Médicale (INSERM), Cognitive Neuroimaging Unit, Université Paris-Saclay, France
| | - Wim Vanduffel
- Laboratory for Neuro- and Psychophysiology, Neurosciences Department, KU Leuven Medical School, Leuven, Belgium; Leuven Brain Institute, KU Leuven, Leuven Belgium; Harvard Medical School, Boston, MA, USA; Massachusetts General Hospital, Martinos Center for Biomedical Imaging, Charlestown, MA, USA
| | - Melanie Wilke
- German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, 37077 Göttingen, Germany; Department of Cognitive Neurology, University Medicine Göttingen, Göttingen, Germany
| | - Igor Kagan
- German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, 37077 Göttingen, Germany.
| | - Christopher I Petkov
- Newcastle University Medical School, Newcastle upon Tyne NE1 7RU, United Kingdom.
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Mitelman SA, Buchsbaum MS, Christian BT, Merrill BM, Buchsbaum BR, Mukherjee J, Lehrer DS. Dopamine receptor density and white mater integrity: 18F-fallypride positron emission tomography and diffusion tensor imaging study in healthy and schizophrenia subjects. Brain Imaging Behav 2021; 14:736-752. [PMID: 30523488 DOI: 10.1007/s11682-018-0012-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dopaminergic dysfunction and changes in white matter integrity are among the most replicated findings in schizophrenia. A modulating role of dopamine in myelin formation has been proposed in animal models and healthy human brain, but has not yet been systematically explored in schizophrenia. We used diffusion tensor imaging and 18F-fallypride positron emission tomography in 19 healthy and 25 schizophrenia subjects to assess the relationship between gray matter dopamine D2/D3 receptor density and white matter fractional anisotropy in each diagnostic group. AFNI regions of interest were acquired for 42 cortical Brodmann areas and subcortical gray matter structures as well as stereotaxically placed in representative white matter areas implicated in schizophrenia neuroimaging literature. Welch's t-test with permutation-based p value adjustment was used to compare means of z-transformed correlations between fractional anisotropy and 18F-fallypride binding potentials in hypothesis-driven regions of interest in the diagnostic groups. Healthy subjects displayed an extensive pattern of predominantly negative correlations between 18F-fallypride binding across a range of cortical and subcortical gray matter regions and fractional anisotropy in rostral white matter regions (internal capsule, frontal lobe, anterior corpus callosum). These patterns were disrupted in subjects with schizophrenia, who displayed significantly weaker overall correlations as well as comparatively scant numbers of significant correlations with the internal capsule and frontal (but not temporal) white matter, especially for dopamine receptor density in thalamic nuclei. Dopamine D2/D3 receptor density and white matter integrity appear to be interrelated, and their decreases in schizophrenia may stem from hyperdopaminergia with dysregulation of dopaminergic impact on axonal myelination.
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Affiliation(s)
- Serge A Mitelman
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA. .,Department of Psychiatry, Division of Child and Adolescent Psychiatry, Elmhurst Hospital Center, 79-01 Broadway, Elmhurst, NY, 11373, USA.
| | - Monte S Buchsbaum
- Departments of Psychiatry and Radiology, University of California, San Diego, 11388 Sorrento Valley Road, San Diego, CA, 92121, USA.,Department of Psychiatry and Human Behavior, Irvine School of Medicine, University of California, 101 The City Dr. S, Orange, CA, 92868, USA
| | - Bradley T Christian
- Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin-Madison, 1500 Highland Avenue, Room T231, Madison, WI, 53705, USA
| | - Brian M Merrill
- Department of Psychiatry, Boonshoft School of Medicine, Wright State University, East Medical Plaza, Dayton, OH, 45408, USA
| | - Bradley R Buchsbaum
- The Rotman Research Institute, Baycrest Centre for Geriatric Care and Department of Psychiatry, University of Toronto, 3560 Bathurst St, Toronto, ON, M6A 2E1, Canada
| | - Jogeshwar Mukherjee
- Department of Radiological Sciences, Preclinical Imaging, Irvine School of Medicine, University of California, Irvine, CA, 92697, USA
| | - Douglas S Lehrer
- Department of Psychiatry, Boonshoft School of Medicine, Wright State University, East Medical Plaza, Dayton, OH, 45408, USA
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Pardridge WM. Treatment of Alzheimer's Disease and Blood-Brain Barrier Drug Delivery. Pharmaceuticals (Basel) 2020; 13:E394. [PMID: 33207605 PMCID: PMC7697739 DOI: 10.3390/ph13110394] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 11/12/2020] [Accepted: 11/13/2020] [Indexed: 12/12/2022] Open
Abstract
Despite the enormity of the societal and health burdens caused by Alzheimer's disease (AD), there have been no FDA approvals for new therapeutics for AD since 2003. This profound lack of progress in treatment of AD is due to dual problems, both related to the blood-brain barrier (BBB). First, 98% of small molecule drugs do not cross the BBB, and ~100% of biologic drugs do not cross the BBB, so BBB drug delivery technology is needed in AD drug development. Second, the pharmaceutical industry has not developed BBB drug delivery technology, which would enable industry to invent new therapeutics for AD that actually penetrate into brain parenchyma from blood. In 2020, less than 1% of all AD drug development projects use a BBB drug delivery technology. The pathogenesis of AD involves chronic neuro-inflammation, the progressive deposition of insoluble amyloid-beta or tau aggregates, and neural degeneration. New drugs that both attack these multiple sites in AD, and that have been coupled with BBB drug delivery technology, can lead to new and effective treatments of this serious disorder.
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Affiliation(s)
- William M Pardridge
- Department of Medicine, University of California, Los Angeles, CA 90024, USA
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Krysiak R, Kowalcze K, Okopień B. Sexual function and depressive symptoms in young women with hypoprolactinaemia. Clin Endocrinol (Oxf) 2020; 93:482-488. [PMID: 32654174 DOI: 10.1111/cen.14283] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 01/08/2023]
Abstract
OBJECTIVE Dopamine agonist treatment may result in hypersexuality in men. The aim of this study was to investigate for the first time female sexual functioning and depressive symptoms in women with very low prolactin levels. DESIGN A prospective case-control study. PATIENTS AND MEASUREMENTS The study population consisted of three age-matched groups of young women with normal, regular menstrual cycles: 15 subjects with cabergoline-induced hypoprolactinaemia (group A), 25 cabergoline-treated individuals with prolactin levels within the reference range (group B) and 30 dopamine agonist-naïve women with normoprolactinemia. Because of low prolactin levels, the dose of cabergoline in group A (but not in group B) was then reduced. Apart from measuring serum levels of prolactin, testosterone, sex hormone-binding globulin, dehydroepiandrosterone sulphate, estradiol and gonadotropins, at the beginning of the study and 6 months later, all included women filled in questionnaires evaluating female sexual function (FSFI) and depressive symptoms (BDI-II). RESULTS At the beginning of the study, there were no differences between groups B and C in the mean total FSFI score, all domain scores and in the BDI-II score. In group A, the total FSFI score and domain scores for desire and arousal were lower, while the BDI-II score was higher than in the remaining study groups. Compared with groups of B and C, women with cabergoline-induced hypoprolactinaemia were also characterized by lower total testosterone levels and lower values of the free androgen index. Cabergoline dose reduction normalized the FSFI score, desire, arousal, the BDI-II score, as well as normalized prolactin, total testosterone and the free androgen index. CONCLUSIONS The obtained results suggest that dopamine agonist-induced hypoprolactinaemia impairs sexual functioning and well-being in young women, as well as that these disturbances are secondary to low prolactin levels, not to specific properties of cabergoline.
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Affiliation(s)
- Robert Krysiak
- Department of Internal Medicine and Clinical Pharmacology, Medical University of Silesia, Katowice, Poland
| | - Karolina Kowalcze
- Department of Pediatrics in Bytom, School of Health Sciences in Katowice, Medical University of Silesia, Katowice, Poland
| | - Bogusław Okopień
- Department of Internal Medicine and Clinical Pharmacology, Medical University of Silesia, Katowice, Poland
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Krysiak R, Szkróbka W, Okopień B. The Impact of Ethinyl Estradiol on Metformin Action on Prolactin Levels in Women with Hyperprolactinemia. Exp Clin Endocrinol Diabetes 2019; 129:22-28. [DOI: 10.1055/a-0921-6420] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Abstract
Background Metformin reduced prolactin levels only in women with hyperprolactinemia.
Objective The purpose of this case-control study was to compare metformin action on lactoctrope function between women receiving oral contraceptive pills and women not using hormonal contraception.
Methods The study included two groups of matched women with elevated prolactin levels and new-onset prediabetes or diabetes. The first group consisted of 20 women using oral contraceptive pills for at least 12 months before entering the study, while the second group included 20 patients not using any hormonal contraception. Over the whole study period, all women were treated with metformin (1.7–3 g daily). Circulating levels of glucose, insulin, prolactin, thyrotropin, free thyroid hormones, adrenocorticotropic hormone, gonadotropins and insulin-like growth factor-1 were measured at the beginning and at the end of the study (16 weeks later).
Results Thirty-eight patients completed the study. Metformin reduced plasma glucose levels and improved insulin sensitivity but the latter effect was stronger in women receiving oral contraceptive pills than in women not using any contraception. Although metformin treatment decreased plasma prolactin levels in both study groups, this effect was stronger in women taking oral contraceptive pills. Only in this group of women, metformin increased plasma luteinizing hormone levels. The changes in plasma prolactin correlated with their baseline insulin sensitivity and the effect of metformin on insulin sensitivity. Metformin did not affect plasma levels of thyrotropin, free thyroxine, free triiodothyronine, follicle-stimulating hormone, adrenocorticotropic hormone and insulin-like growth factor-1.
Conclusions The obtained results suggest that the effect of metformin on overactive lactotropes depends on estrogen levels.
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Affiliation(s)
- Robert Krysiak
- Department of Internal Medicine and Clinical Pharmacology, Medical University of Silesia, Katowice, Poland
| | - Witold Szkróbka
- Department of Internal Medicine and Clinical Pharmacology, Medical University of Silesia, Katowice, Poland
| | - Bogusław Okopień
- Department of Internal Medicine and Clinical Pharmacology, Medical University of Silesia, Katowice, Poland
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Changes in Endogenous Dopamine Induced by Methylphenidate Predict Functional Connectivity in Nonhuman Primates. J Neurosci 2018; 39:1436-1444. [PMID: 30530859 DOI: 10.1523/jneurosci.2513-18.2018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/09/2018] [Accepted: 12/04/2018] [Indexed: 11/21/2022] Open
Abstract
Dopamine (DA) levels in the striatum are increased by many therapeutic drugs, such as methylphenidate (MPH), which also alters behavioral and cognitive functions thought to be controlled by the PFC dose-dependently. We linked DA changes and functional connectivity (FC) using simultaneous [18F]fallypride PET and resting-state fMRI in awake male rhesus monkeys after oral administration of various doses of MPH. We found a negative correlation between [18F]fallypride nondisplaceable binding potential (BPND) and MPH dose in the head of the caudate (hCd), demonstrating increased extracellular DA resulting from MPH administration. The decreased BPND was negatively correlated with FC between the hCd and the PFC. Subsequent voxelwise analyses revealed negative correlations with FC between the hCd and the dorsolateral PFC, hippocampus, and precuneus. These results, showing that MPH-induced changes in DA levels in the hCd predict resting-state FC, shed light on a mechanism by which changes in striatal DA could influence function in the PFC.SIGNIFICANCE STATEMENT Dopamine transmission is thought to play an essential role in shaping large scale-neural networks that underlie cognitive functions. It is the target of therapeutic drugs, such as methylphenidate (Ritalin), which blocks the dopamine transporter, thereby increasing extracellular dopamine levels. Methylphenidate is used extensively to treat attention deficit hyperactivity disorder, even though its effects on cognitive functions and their underlying neural mechanisms are not well understood. To date, little is known about the link between changes in dopamine levels and changes in functional brain organization. Using simultaneous PET/MR imaging, we show that methylphenidate-induced changes in endogenous dopamine levels in the head of the caudate predict changes in resting-state functional connectivity between this structure and the prefrontal cortex, precuneus, and hippocampus.
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Zhang X, Dunlow R, Blackman BN, Swenson RE. Optimization of 18 F-syntheses using 19 F-reagents at tracer-level concentrations and liquid chromatography/tandem mass spectrometry analysis: Improved synthesis of [ 18 F]MDL100907. J Labelled Comp Radiopharm 2018; 61:427-437. [PMID: 29336065 DOI: 10.1002/jlcr.3606] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 12/13/2017] [Accepted: 01/05/2018] [Indexed: 12/19/2022]
Abstract
Traditional radiosynthetic optimization faces the challenges of high radiation exposure, cost, and inability to perform serial reactions due to tracer decay. To accelerate tracer development, we have developed a strategy to simulate radioactive 18 F-syntheses by using tracer-level (nanomolar) non-radioactive 19 F-reagents and LC-MS/MS analysis. The methodology was validated with fallypride synthesis under tracer-level 19 F-conditions, which showed reproducible and comparable results with radiosynthesis, and proved the feasibility of this process. Using this approach, the synthesis of [18 F]MDL100907 was optimized under 19 F-conditions with greatly improved yield. The best conditions were successfully transferred to radiosynthesis. A radiochemical yield of 19% to 22% was achieved with the radiochemical purity >99% and the molar activity 38.8 to 53.6 GBq/ μmol (n = 3). The tracer-level 19 F-approach provides a high-throughput and cost-effective process to optimize radiosynthesis with reduced radiation exposure. This new method allows medicinal and synthetic chemists to optimize radiolabeling conditions without the need to use radioactivity.
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Affiliation(s)
- Xiang Zhang
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, MD, USA
| | - Ryan Dunlow
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, MD, USA
| | - Burchelle N Blackman
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, MD, USA
| | - Rolf E Swenson
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, MD, USA
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Krysiak R, Szkróbka W, Okopień B. Effect of Metformin on Hypothalamic-Pituitary-Thyroid Axis Activity in Elderly Antipsychotic-Treated Women With Type 2 Diabetes and Subclinical Hypothyroidism: A Preliminary Study. J Clin Pharmacol 2017; 58:586-592. [PMID: 29251783 DOI: 10.1002/jcph.1048] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 10/25/2017] [Indexed: 12/14/2022]
Abstract
Metformin was found to reduce elevated serum thyrotropin levels, and this effect was partially determined by endogenous dopaminergic tone. The aim of this study was to compare the effect of metformin treatment on hypothalamic-pituitary-thyroid axis activity in elderly women with subclinical hypothyroidism treated with antipsychotic agents and not receiving this drug. The study population consisted of 34 elderly women with subclinical hypothyroidism, 16 of whom received antipsychotic drugs. Because of coexistent type 2 diabetes, these women were treated with metformin (2.55-3 g daily). Glucose homeostasis markers as well as serum levels of thyrotropin, free thyroid hormones and prolactin were measured at the beginning of the study and 6 months later. Thirty women completed the study. With the exception of prolactin, baseline serum levels of the assessed hormones were comparable in both study groups. Although metformin reduced serum thyrotropin levels in both groups, this effect was more pronounced in the antipsychotic-treated than in the antipsychotic-naive patients. The effect on serum prolactin was observed only in antipsychotic-treated patients. The impact on serum thyrotropin levels correlated with improvement in insulin sensitivity and with a reduction in prolactin levels. Free thyroxine and free triiodothyronine remained at a similar level throughout the study. The obtained results indicate that metformin reduces serum thyrotropin levels in elderly women, and this effect is particularly pronounced in women with diminished dopaminergic transmission.
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Affiliation(s)
- Robert Krysiak
- Department of Internal Medicine and Clinical Pharmacology, Medical University of Silesia, Katowice, Poland
| | - Witold Szkróbka
- Department of Internal Medicine and Clinical Pharmacology, Medical University of Silesia, Katowice, Poland
| | - Bogusław Okopień
- Department of Internal Medicine and Clinical Pharmacology, Medical University of Silesia, Katowice, Poland
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Sex-dependent effect of metformin on hypothalamic-pituitary-thyroid axis activity in patients with subclinical hypothyroidism. Pharmacol Rep 2016; 68:1115-1119. [PMID: 27588386 DOI: 10.1016/j.pharep.2016.07.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 06/27/2016] [Accepted: 07/14/2016] [Indexed: 12/18/2022]
Abstract
BACKGROUND Metformin was found to reduce elevated serum thyrotropin levels. No previous study has compared the effect of this drug on serum levels of thyrotropin and thyroid hormones between men and women. METHODS The study included 23 women and 12 men with subclinical hypothyroidism, who because of coexisting diabetes or impaired fasting glucose were treated with metformin (1.7-3.0g daily). Fasting plasma glucose levels, the homeostatic model assessment 1 of insulin resistance ratio (HOMA1-IR), glycated hemoglobin, serum levels of thyrotropin, free and total thyroid hormones and prolactin, as well as thyroid peroxidase and thyroglobulin antibodies were assessed at baseline and after 4 months of metformin treatment. RESULTS Baseline serum levels of thyrotropin, free thyroxine and free triiodothyronine, as well as a percentage of patients with positive thyroid peroxidase and thyroglobulin antibodies were comparable in both sexes. Metformin treatment reduced plasma glucose and insulin resistance, irrespective of the gender. However, only in women, metformin decreased serum thyrotropin levels. Neither in men nor in women, metformin affected serum levels of thyroid hormone and prolactin, as well as in the subgroups of patients with thyroiditis thyroid antibody titers. CONCLUSIONS The obtained results suggest that sex may determine the effect of metformin on hypothalamic-pituitary-thyroid axis activity.
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Mukherjee J, Constantinescu CC, Hoang AT, Jerjian T, Majji D, Pan ML. Dopamine D3 receptor binding of (18)F-fallypride: Evaluation using in vitro and in vivo PET imaging studies. Synapse 2015; 69:577-91. [PMID: 26422464 DOI: 10.1002/syn.21867] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 08/25/2015] [Accepted: 09/19/2015] [Indexed: 12/17/2022]
Abstract
Identification of dopamine D3 receptors (D3R) in vivo is important to understand several brain functions related to addiction. The goal of this work was to identify D3R binding of the dopamine D2 receptor (D2R)/D3R imaging agent, (18)F-fallypride. Brain slices from male Sprague-Dawley rats (n = 6) and New Zealand White rabbits (n = 6) were incubated with (18)F-fallypride and D3R selective agonist (R)-7-OH-DPAT (98-fold D3R selective). Rat slices were also treated with BP 897 (68-fold D3R selective partial agonist) and NGB 2904 (56-fold D3R selective antagonist). In vivo rat studies (n = 6) were done on Inveon PET using 18-37 MBq (18)F-fallypride and drug-induced displacement by (R)-7-OH-DPAT, BP 897 and NGB 2904. PET/CT imaging of wild type (WT, n = 2) and D2R knock-out (KO, n = 2) mice were carried out with (18)F-fallypride. (R)-7-OH-DPAT displaced binding of (18)F-fallypride, both in vitro and in vivo. In vitro, at 10 nM (R)-7-OH-DPAT, (18)F-fallypride binding in the rat ventral striatum (VST) and dorsal striatum (DST) and rabbit nucleus accumbens were reduced by ∼10-15%. At 10 μM (R)-7-OH-DPAT all regions in rat and rabbit were reduced by ≥85%. In vivo reductions for DST and VST before and after (R)-7-OH-DPAT were: low-dose (0.015 mg kg(-1)) DST -22%, VST -29%; high-dose (1.88 mg kg(-1)) DST -58%, VST -77%, suggesting D3R/D2R displacement. BP 897 and NGB 2904 competed with (18)F-fallypride in vitro, but unlike BP 897, NGB 2904 did not displace (18)F-fallypride in vivo. The D2R KO mice lacked (18)F-fallypride binding in the DST. In summary, our findings suggest that up to 20% of (18)F-fallypride may be bound to D3R sites in vivo.
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Affiliation(s)
- Jogeshwar Mukherjee
- Department of Radiological Sciences, Preclinical Imaging, University of California, Irvine, California, 92697
| | - Cristian C Constantinescu
- Department of Radiological Sciences, Preclinical Imaging, University of California, Irvine, California, 92697
| | - Angela T Hoang
- Department of Radiological Sciences, Preclinical Imaging, University of California, Irvine, California, 92697
| | - Taleen Jerjian
- Department of Radiological Sciences, Preclinical Imaging, University of California, Irvine, California, 92697
| | - Divya Majji
- Department of Radiological Sciences, Preclinical Imaging, University of California, Irvine, California, 92697
| | - Min-Liang Pan
- Department of Radiological Sciences, Preclinical Imaging, University of California, Irvine, California, 92697
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Abstract
Understanding the heritability of neural systems linked to psychopathology is not sufficient to implicate them as intergenerational neural mediators. By closely examining how individual differences in neural phenotypes and psychopathology cosegregate as they fall through the family tree, we can identify the brain systems that underlie the parent-to-child transmission of psychopathology. Although research has identified genes and neural circuits that contribute to the risk of developing anxiety and depression, the specific neural systems that mediate the inborn risk for these debilitating disorders remain unknown. In a sample of 592 young rhesus monkeys that are part of an extended multigenerational pedigree, we demonstrate that metabolism within a tripartite prefrontal-limbic-midbrain circuit mediates some of the inborn risk for developing anxiety and depression. Importantly, although brain volume is highly heritable early in life, it is brain metabolism-not brain structure-that is the critical intermediary between genetics and the childhood risk to develop stress-related psychopathology.
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In vivo PET quantification of the dopamine transporter in rat brain with [18F]LBT-999. Nucl Med Biol 2014; 41:106-13. [DOI: 10.1016/j.nucmedbio.2013.09.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 08/22/2013] [Accepted: 09/23/2013] [Indexed: 11/23/2022]
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Boado RJ, Hui EKW, Lu JZ, Sumbria RK, Pardridge WM. Blood-brain barrier molecular trojan horse enables imaging of brain uptake of radioiodinated recombinant protein in the rhesus monkey. Bioconjug Chem 2013; 24:1741-9. [PMID: 24059813 DOI: 10.1021/bc400319d] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Recombinant proteins are large molecule drugs that do not cross the blood-brain barrier (BBB). However, BBB-penetration of protein therapeutics is enabled by re-engineering the recombinant protein as IgG fusion proteins. The IgG domain is a monoclonal antibody (mAb) against an endogenous BBB receptor-mediated transport system, such as the human insulin receptor (HIR), and acts as a molecular Trojan horse to ferry the fused protein across the BBB. In the present study, a recombinant lysosomal enzyme, iduronate 2-sulfatase (IDS), is fused to the HIRMAb, and BBB penetration of the IDS alone vs the HIRMAb-IDS fusion protein is compared in the Rhesus monkey. Recombinant IDS and the HIRMAb-IDS fusion protein were radiolabeled with indirect iodination with the [(125)I]-Bolton-Hunter reagent and with direct iodination with Iodogen/[(125)I]-idodine. IDS and the HIRMAb-IDS fusion protein have comparable plasma pharmacokinetics and uptake by peripheral organs. IDS does not cross the BBB. The HIRMAb-IDS fusion protein crosses the BBB and the brain uptake is 1% of injected dose/brain. Brain imaging shows HIRMAb-IDS penetration to all parts of brain, and immunoprecipitation of brain radioactivity shows intact fusion protein in brain. The use of BBB molecular Trojan horses enables brain imaging of recombinant proteins that are re-engineered for BBB transport.
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Affiliation(s)
- Ruben J Boado
- Department of Medicine, University of California, Los Angeles , Los Angeles, California 90024, United States
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Nagano-Saito A, Dagher A, Booij L, Gravel P, Welfeld K, Casey KF, Leyton M, Benkelfat C. Stress-induced dopamine release in human medial prefrontal cortex--18F-fallypride/PET study in healthy volunteers. Synapse 2013; 67:821-30. [PMID: 23939822 DOI: 10.1002/syn.21700] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 06/26/2013] [Accepted: 07/27/2013] [Indexed: 12/12/2022]
Abstract
BACKGROUND In laboratory animals, environmental stressors markedly activate the mesocortical dopamine system. The present study tested whether this occurs in humans. METHODS The effects of a laboratory psychological stressor (Montreal Imaging Stress Task, MIST) on mesocortical dopamine release in healthy young adults (11 males, mean age ± SD, 20.6 ± 2.4 years) was measured using positron emission tomography and [(18)F]fallypride. Each subject was scanned in two separate days in counterbalanced order: one with the MIST and one with the control task. Binding potential (BP ND ) maps of the whole brain were calculated for each scan, using a simplified reference tissue compartmental model. Then BP ND was compared between subjects. Heart rate, galvanic skin response, and salivary cortisol level were measured during the scans. RESULTS The psychological stressor significantly decreased [(18)F]fallypride binding values in the dorsal part of the medial prefrontal cortex (dmPFC), corresponding to the rostal part of the cingulate motor zone. The greater the stress-induced decrease in [(18)F]fallypride binding in the dmPFC, the greater the stress-induced increases in heart rate. CONCLUSIONS The present study provides evidence of stress-induced dopamine release in the mPFC in humans, in vivo.
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Affiliation(s)
- Atsuko Nagano-Saito
- Department of Psychiatry, McGill University, Montréal, QC, H3A 1A1, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, QC, H3A 2B4, Canada
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Boado RJ, Lu JZ, Hui EKW, Sumbria RK, Pardridge WM. Pharmacokinetics and brain uptake in the rhesus monkey of a fusion protein of arylsulfatase a and a monoclonal antibody against the human insulin receptor. Biotechnol Bioeng 2012. [PMID: 23192358 DOI: 10.1002/bit.24795] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Metachromatic leukodystrophy (MLD) is a lysosomal storage disorder of the brain caused by mutations in the gene encoding the lysosomal sulfatase, arylsulfatase A (ASA). It is not possible to treat the brain in MLD with recombinant ASA, because the enzyme does not cross the blood-brain barrier (BBB). In the present investigation, a BBB-penetrating IgG-ASA fusion protein is engineered and expressed, where the ASA monomer is fused to the carboxyl terminus of each heavy chain of an engineered monoclonal antibody (MAb) against the human insulin receptor (HIR). The HIRMAb crosses the BBB via receptor-mediated transport on the endogenous BBB insulin receptor, and acts as a molecular Trojan horse to ferry the ASA into brain from blood. The HIRMAb-ASA is expressed in stably transfected Chinese hamster ovary cells grown in serum free medium, and purified by protein A affinity chromatography. The fusion protein retains high affinity binding to the HIR, EC50 = 0.34 ± 0.11 nM, and retains high ASA enzyme activity, 20 ± 1 units/mg. The HIRMAb-ASA fusion protein is endocytosed and triaged to the lysosomal compartment in MLD fibroblasts. The fusion protein was radio-labeled with the Bolton-Hunter reagent, and the [(125) I]-HIRMAb-ASA rapidly penetrates the brain in the Rhesus monkey following intravenous administration. Film and emulsion autoradiography of primate brain shows global distribution of the fusion protein throughout the monkey brain. These studies describe a new biological entity that is designed to treat the brain of humans with MLD following non-invasive, intravenous infusion of an IgG-ASA fusion protein.
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Affiliation(s)
- Ruben J Boado
- ArmaGen Technologies, Inc., Santa Monica, CA 90401, USA
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Abstract
The blood-brain barrier (BBB) prevents the brain uptake of most pharmaceuticals. This property arises from the epithelial-like tight junctions within the brain capillary endothelium. The BBB is anatomically and functionally distinct from the blood-cerebrospinal fluid barrier at the choroid plexus. Certain small molecule drugs may cross the BBB via lipid-mediated free diffusion, providing the drug has a molecular weight <400 Da and forms <8 hydrogen bonds. These chemical properties are lacking in the majority of small molecule drugs, and all large molecule drugs. Nevertheless, drugs can be reengineered for BBB transport, based on the knowledge of the endogenous transport systems within the BBB. Small molecule drugs can be synthesized that access carrier-mediated transport (CMT) systems within the BBB. Large molecule drugs can be reengineered with molecular Trojan horse delivery systems to access receptor-mediated transport (RMT) systems within the BBB. Peptide and antisense radiopharmaceuticals are made brain-penetrating with the combined use of RMT-based delivery systems and avidin-biotin technology. Knowledge on the endogenous CMT and RMT systems expressed at the BBB enable new solutions to the problem of BBB drug transport.
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Constantinescu CC, Coleman RA, Pan ML, Mukherjee J. Striatal and extrastriatal microPET imaging of D2/D3 dopamine receptors in rat brain with [¹⁸F]fallypride and [¹⁸F]desmethoxyfallypride. Synapse 2011; 65:778-87. [PMID: 21218455 DOI: 10.1002/syn.20904] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Accepted: 12/23/2010] [Indexed: 11/07/2022]
Abstract
In this study, we compared two different D(2/3) receptor ligands, [¹⁸F]fallypride and [¹⁸F]desmethoxyfallypride ([¹⁸F]DMFP) with respect to the duration of the scan, visualization of extrastriatal receptors, and binding potentials (BP(ND) ) in the rat brain. In addition, we studied the feasibility of using these tracers following a period of awake tracer uptake, during which the animal may perform a behavioral task. Male Sprague-Dawley rats were imaged with [¹⁸F]fallypride and with [¹⁸F]DMFP in four different studies using microPET. All scans were performed under isoflurane anesthesia. The first (test) and second (retest) study were 150-min baseline scans. No retest scans were performed with [¹⁸F]DMFP. A third study was a 60-min awake uptake of radiotracer followed by a 90-min scan. A fourth study was a 150-min competition scan with haloperidol (0.2 mg/kg) administered via tail vein at 90-min post-[¹⁸F]fallypride injection and 60-min post-[¹⁸F]DMFP. For the test-retest studies, BP(ND) was measured using both Logan noninvasive (LNI) method and the interval ratios (ITR) method. Cerebellum was used as a reference region. For the third study, the binding was measured only with the ITR method, and the results were compared to the baseline results. Studies showed that the average transient equilibrium time in the dorsal striatum (DSTR) was at 90 min for [¹⁸F]fallypride and 30 min for [¹⁸F]DMFP. The average BP(ND) for [¹⁸F]fallypride was 14.4 in DSTR, 6.8 in ventral striatum (VSTR), 1.3 in substantia nigra/ventral tegmental area (SN/VTA), 1.4 in colliculi (COL), and 1.5 in central gray area. In the case of [¹⁸F]DMFP, the average BP(ND) values were 2.2 in DSTR, 2.7 in VSTR, and 0.8 in SN/VTA. The haloperidol blockade showed detectable decrease in binding of both tracers in striatal regions with a faster displacement of [¹⁸F]DMFP. No significant changes in BP(ND) of [¹⁸F]fallypride due to the initial awake state of the animal were found, whereas BP(ND) of [¹⁸F]DMFP was significantly higher in the awake state compared to baseline. We were able to demonstrate that dynamic PET using MicroPET Inveon allows quantification of both striatal and extrastriatal [¹⁸F]fallypride binding in rats in vivo. Quantification of the striatal regions could be achieved with [¹⁸F]DMFP.
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Affiliation(s)
- Cristian C Constantinescu
- Preclinical Imaging, Department of Psychiatry and Human Behavior, University of California Irvine, Irvine, California 92697, USA.
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18F-fallypride binding potential in patients with schizophrenia compared to healthy controls. Schizophr Res 2010; 122:43-52. [PMID: 20655709 PMCID: PMC3278159 DOI: 10.1016/j.schres.2010.03.043] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Revised: 03/26/2010] [Accepted: 03/30/2010] [Indexed: 11/20/2022]
Abstract
BACKGROUND Molecular imaging of dopaminergic parameters has contributed to the dopamine hypothesis of schizophrenia, expanding our understanding of pathophysiology, clinical phenomenology and treatment. Our aim in this study was to compare (18)F-fallypride binding potential BP(ND) in a group of patients with schizophrenia-spectrum illness vs. controls, with a particular focus on the cortex and thalamus. METHODS We acquired (18)F-fallypride positron emission tomography images on 33 patients with schizophrenia spectrum disorder (28 with schizophrenia; 5 with schizoaffective disorder) and 18 normal controls. Twenty-four patients were absolutely neuroleptic naïve and nine were previously medicated, although only four had a lifetime neuroleptic exposure of greater than two weeks. Parametric images of (18)F-fallypride BP(ND) were calculated to compare binding across subjects. RESULTS Decreased BP(ND) was observed in the medial dorsal nucleus of the thalamus, prefrontal cortex, lateral temporal lobe and primary auditory cortex. These findings were most marked in subjects who had never previously received medication. CONCLUSIONS The regions with decreased BP(ND) tend to match brain regions previously reported to show alterations in metabolic activity and blood flow and areas associated with the symptoms of schizophrenia.
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Kobiella A, Vollstädt-Klein S, Bühler M, Graf C, Buchholz HG, Bernow N, Yakushev IY, Landvogt C, Schreckenberger M, Gründer G, Bartenstein P, Fehr C, Smolka MN. Human dopamine receptor D2/D3 availability predicts amygdala reactivity to unpleasant stimuli. Hum Brain Mapp 2010; 31:716-26. [PMID: 19904802 DOI: 10.1002/hbm.20900] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Dopamine (DA) modulates the response of the amygdala. However, the relation between dopaminergic neurotransmission in striatal and extrastriatal brain regions and amygdala reactivity to affective stimuli has not yet been established. To address this issue, we measured DA D2/D3 receptor (DRD2/3) availability in twenty-eight healthy men (nicotine-dependent smokers and never-smokers) using positron emission tomography with [18F]fallypride. In the same group of participants, amygdala response to unpleasant visual stimuli was determined using blood oxygen level-dependent (BOLD) functional magnetic resonance imaging. The effects of DRD2/3 availability in emotion-related brain regions and nicotine dependence on amygdala response to unpleasant stimuli were examined by multiple regression analysis. We observed enhanced prefrontal DRD2/3 availability in those individuals with higher amygdala response to unpleasant stimuli. As compared to never-smokers, smokers showed an attenuated amygdala BOLD response to unpleasant stimuli. Thus, individuals with high prefrontal DRD2/3 availability may be more responsive toward aversive and stressful information. Through this mechanism, dopaminergic neurotransmission might influence vulnerability for affective and anxiety disorders. Neuronal reactivity to unpleasant stimuli seems to be reduced by smoking. This observation could explain increased smoking rates in individuals with mental disorders.
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Affiliation(s)
- Andrea Kobiella
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health, University of Heidelberg, Mannheim, Germany
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Characterization of the dopamine receptor system in adult rhesus monkeys exposed to cocaine throughout gestation. Psychopharmacology (Berl) 2010; 210:481-8. [PMID: 20401746 PMCID: PMC2878372 DOI: 10.1007/s00213-010-1847-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Accepted: 03/23/2010] [Indexed: 10/19/2022]
Abstract
RATIONALE Cocaine use during pregnancy is associated with alterations in the dopamine (DA) system in the fetal brain. However, little is known about the effects of prenatal cocaine exposure on the postnatal dopaminergic system. OBJECTIVES The objective of the study was to examine DA receptor function in adult monkeys that were prenatally exposed to cocaine. MATERIALS AND METHODS Male and female rhesus monkeys (approximately 13 years old) that had been prenatally exposed to cocaine (n = 10) and controls (n = 10) were used in all studies. First, DA D2-like receptor availability was assessed using positron emission tomography and the D2-like receptor radiotracer [(18)F]fluoroclebopride (FCP). Next, D(3) receptor function was assessed by measuring quinpirole-induced yawning (0.03-0.3 mg/kg). Finally, D1-like receptor function was examined by measuring eye blinking elicited by the high-efficacy D1-like receptor agonist SKF81297 (0.3-3.0 mg/kg). RESULTS There were no differences between groups or sexes in D2-like receptor availability in the caudate nucleus, putamen or amygdala. However, quinpirole elicited significantly more yawns in prenatally cocaine-exposed monkeys compared with control monkeys. A significant correlation between gestational dose of cocaine and peak effects of quinpirole was observed. In all monkeys, administration of SKF81297 elicited dose-dependent increases in eye blinks that did not differ between groups. CONCLUSIONS These findings suggest that prenatal cocaine exposure can have long-term effects on DA D(3) receptor function in adults.
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Moon BS, Park JH, Lee HJ, Kim JS, Kil HS, Lee BS, Chi DY, Lee BC, Kim YK, Kim SE. Highly efficient production of [(18)F]fallypride using small amounts of base concentration. Appl Radiat Isot 2010; 68:2279-84. [PMID: 20609592 DOI: 10.1016/j.apradiso.2010.06.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 06/03/2010] [Accepted: 06/16/2010] [Indexed: 11/19/2022]
Abstract
To minimize the base concentration of a phase-transfer catalyst, [(18)F]fluoride was extracted from (18)O-enriched water trapped on an activated ion exchange cartridge (Chromafix PS-HCO(3)) using different concentrations of tetrabutylammonium bicarbonate (TBAHCO(3)) or Kryptofix 2.2.2./K(2)CO(3) in organic solvents such as CH(3)CN/H(2)O or MeOH/H(2)O. The optimal labeling condition for [(18)F]fallypride with automated synthesis was that 2 mg of tosyl-fallypride in acetonitrile (1 mL) was heated at 100 degrees C for 10 min using 40% TBAHCO(3) (10 microL). [(18)F]Fallypride was obtained with a high radiochemical yield of approximately 68+/-1.6% (decay-corrected, n=42) with a total synthesis time of 51+/-1.2 min, including HPLC purification and solid-phase purification for the final formulation.
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Affiliation(s)
- Byung Seok Moon
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam 463-707, Republic of Korea
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Vandehey NT, Moirano JM, Converse AK, Holden JE, Mukherjee J, Murali D, Nickles RJ, Davidson RJ, Schneider ML, Christian BT. High-affinity dopamine D2/D3 PET radioligands 18F-fallypride and 11C-FLB457: a comparison of kinetics in extrastriatal regions using a multiple-injection protocol. J Cereb Blood Flow Metab 2010; 30:994-1007. [PMID: 20040928 PMCID: PMC2897717 DOI: 10.1038/jcbfm.2009.270] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
(18)F-Fallypride and (11)C-FLB457 are commonly used PET radioligands for imaging extrastriatal dopamine D(2)/D(3) receptors, but differences in their in vivo kinetics may affect the sensitivity for measuring subtle changes in receptor binding. Focusing on regions of low binding, a direct comparison of the kinetics of (18)F-fallypride and (11)C-FLB457 was made using a MI protocol. Injection protocols were designed to estimate K(1), k(2), f(ND)k(on), B(max), and k(off) in the midbrain and cortical regions of the rhesus monkey. (11)C-FLB457 cleared from the arterial plasma faster and yielded a ND space distribution volume (K(1)/k(2)) that is three times higher than (18)F-fallypride, primarily due to a slower k(2) (FAL:FLB; k(2)=0.54 min(-1):0.18 min(-1)). The dissociation rate constant, k(off), was slower for (11)C-FLB457, resulting in a lower K(Dapp) than (18)F-fallypride (FAL:FLB; 0.39 nM:0.13 nM). Specific D(2)/D(3) binding could be detected in the cerebellum for (11)C-FLB457 but not (18)F-fallypride. Both radioligands can be used to image extrastriatal D(2)/D(3) receptors, with (11)C-FLB457 providing greater sensitivity to subtle changes in low-receptor-density cortical regions and (18)F-fallypride being more sensitive to endogenous dopamine displacement in medium-to-high-receptor-density regions. In the presence of specific D(2)/D(3) binding in the cerebellum, reference region analysis methods will give a greater bias in BP(ND) with (11)C-FLB457 than with (18)F-fallypride.
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Affiliation(s)
- Nicholas T Vandehey
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA.
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Christian BT, Fox AS, Oler JA, Vandehey NT, Murali D, Rogers J, Oakes TR, Shelton SE, Davidson RJ, Kalin NH. Serotonin transporter binding and genotype in the nonhuman primate brain using [C-11]DASB PET. Neuroimage 2009; 47:1230-6. [PMID: 19505582 DOI: 10.1016/j.neuroimage.2009.05.090] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 05/21/2009] [Accepted: 05/27/2009] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED The length polymorphism of the serotonin (5-HT) transporter gene promoter region has been implicated in altered 5-HT function and, in turn, neuropsychiatric illnesses, such as anxiety and depression. The nonhuman primate has been used as a model to study anxiety-related mechanisms in humans based upon similarities in behavior and the presence of a similar 5-HT transporter gene polymorphism. Stressful and threatening contexts in the nonhuman primate model have revealed 5-HT transporter genotype dependent differences in regional glucose metabolism. Using the rhesus monkey, we examined the extent to which serotonin transporter genotype is associated with 5-HT transporter binding in brain regions implicated in emotion-related pathology. METHODS Genotype data and high resolution PET scans were acquired in 29 rhesus (Macaca mulatta) monkeys. [C-11]DASB dynamic PET scans were acquired for 90 min in the anesthetized animals and images of distribution volume ratio (DVR) were created to serve as a metric of 5-HT transporter binding for group comparison based on a reference region method of analysis. Regional and voxelwise statistical analysis were performed with corrections for anatomical differences in gray matter probability, sex, age and radioligand mass. RESULTS There were no significant differences when comparing l/l homozygotes with s-carriers in the regions of the brain implicated in anxiety and mood related illnesses (amygdala, striatum, thalamus, raphe nuclei, temporal and prefrontal cortex). There was a significant sex difference in 5-HT transporter binding in all regions with females having 18%-28% higher DVR than males. CONCLUSIONS Because these findings are consistent with similar genotype findings in humans, this further strengthens the use of the rhesus model for studying anxiety-related neuropathologies.
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Affiliation(s)
- B T Christian
- Department of Psychiatry, Harlow Primate Center, University of Wisconsin-Madison, USA.
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