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Hámor PU, Knackstedt LA, Schwendt M. The role of metabotropic glutamate receptors in neurobehavioral effects associated with methamphetamine use. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2023; 168:177-219. [PMID: 36868629 DOI: 10.1016/bs.irn.2022.10.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Metabotropic glutamate (mGlu) receptors are expressed throughout the central nervous system and act as important regulators of drug-induced neuroplasticity and behavior. Preclinical research suggests that mGlu receptors play a critical role in a spectrum of neural and behavioral consequences arising from methamphetamine (meth) exposure. However, an overview of mGlu-dependent mechanisms linked to neurochemical, synaptic, and behavioral changes produced by meth has been lacking. This chapter provides a comprehensive review of the role of mGlu receptor subtypes (mGlu1-8) in meth-induced neural effects, such as neurotoxicity, as well as meth-associated behaviors, such as psychomotor activation, reward, reinforcement, and meth-seeking. Additionally, evidence linking altered mGlu receptor function to post-meth learning and cognitive deficits is critically evaluated. The chapter also considers the role of receptor-receptor interactions involving mGlu receptors and other neurotransmitter receptors in meth-induced neural and behavioral changes. Taken together, the literature indicates that mGlu5 regulates the neurotoxic effects of meth by attenuating hyperthermia and possibly through altering meth-induced phosphorylation of the dopamine transporter. A cohesive body of work also shows that mGlu5 antagonism (and mGlu2/3 agonism) reduce meth-seeking, though some mGlu5-blocking drugs also attenuate food-seeking. Further, evidence suggests that mGlu5 plays an important role in extinction of meth-seeking behavior. In the context of a history of meth intake, mGlu5 also co-regulates aspects of episodic memory, with mGlu5 stimulation restoring impaired memory. Based on these findings, we propose several avenues for the development of novel pharmacotherapies for Methamphetamine Use Disorder based on the selective modulation mGlu receptor subtype activity.
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Affiliation(s)
- Peter U Hámor
- Department of Psychology, University of Florida, Gainesville, FL, United States; Center for Addiction Research and Education, University of Florida, Gainesville, FL, United States; Department of Pharmacology, Weill Cornell Medicine, Cornell University, New York, NY, United States
| | - Lori A Knackstedt
- Department of Psychology, University of Florida, Gainesville, FL, United States; Center for Addiction Research and Education, University of Florida, Gainesville, FL, United States
| | - Marek Schwendt
- Department of Psychology, University of Florida, Gainesville, FL, United States; Center for Addiction Research and Education, University of Florida, Gainesville, FL, United States.
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Kimura M, Oda Y, Hirose Y, Kimura H, Yoshino K, Niitsu T, Kanahara N, Shirayama Y, Hashimoto K, Iyo M. Upregulation of heat-shock protein HSP-70 and glutamate transporter-1/glutamine synthetase in the striatum and hippocampus in haloperidol-induced dopamine-supersensitivity-state rats. Pharmacol Biochem Behav 2021; 211:173288. [PMID: 34653399 DOI: 10.1016/j.pbb.2021.173288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/07/2021] [Accepted: 10/07/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND The excessive blockade of dopamine D2 receptors (DRD2s) with long-term antipsychotic treatment is known to induce a dopamine supersensitivity state (DSS). The mechanism of DSS is speculated to be a compensatory up-regulation of DRD2s, but an excess blockade of DRD2s can also cause glutamatergic neuronal damage. Herein, we investigated whether antipsychotic-induced neuronal damage plays a role in the development of DSS. METHODS Haloperidol (HAL; 0.75 mg/kg/day for 14 days) or vehicle was administered to rats via an osmotic mini-pump. Haloperidol-treated rats were divided into groups of DSS rats and non-DSS rats based on their voluntary locomotion data. We then determined the tissue levels of glutamate transporter-1 (GLT-1)/glutamine synthetase (GS) and heat shock protein-70 (HSP-70) in the rats' brain regions. RESULTS The levels of HSP-70 in the striatum and CA-3 region of the DSS rats were significantly higher than those of the control and non-DSS rats, whereas the dentate gyrus HSP-70 levels in both the DSS and non-DSS rats were increased versus the controls. The levels of GLT-1/GS in the CA-3 and nucleus accumbens were increased in the DSS rats. CONCLUSIONS These results suggest that the DSS rats experienced striatal neuronal damage and indicate that a HAL-induced upregulation of HSP-70 and the GLT-1/GS system in the CA3 may be involved in the development of DSS. It remains unknown why the non-DSS rats did not suffer neuronal damage. In view of the need for therapeutic strategies for treatment-resistant schizophrenia, dopamine supersensitivity psychosis, and tardive dyskinesia, further investigations of our findings are warranted.
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Affiliation(s)
- Makoto Kimura
- Department of Psychiatry, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuou-ku, Chiba, Chiba 260-8670, Japan
| | - Yasunori Oda
- Department of Psychiatry, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuou-ku, Chiba, Chiba 260-8670, Japan.
| | - Yuki Hirose
- Department of Psychiatry, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuou-ku, Chiba, Chiba 260-8670, Japan
| | - Hiroshi Kimura
- Department of Psychiatry, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuou-ku, Chiba, Chiba 260-8670, Japan; Department of Psychiatry, School of Medicine, International University of Health and Welfare, 4-3 Kozunomori, Narita, Chiba 286-8686, Japan
| | - Kouhei Yoshino
- Department of Psychiatry, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuou-ku, Chiba, Chiba 260-8670, Japan
| | - Tomihisa Niitsu
- Department of Psychiatry, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuou-ku, Chiba, Chiba 260-8670, Japan
| | - Nobuhisa Kanahara
- Division of Medical Treatment and Rehabilitation, Chiba University Center for Forensic Mental Health, 1-8-1 Inohana, Chuou-ku, Chiba, Chiba 260-8670, Japan
| | - Yukihiko Shirayama
- Department of Psychiatry, Teikyo University Chiba Medical Center, 3426-3 Anesaki, Ichihara, Chiba 290-0111, Japan
| | - Kenji Hashimoto
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 1-8-1 Inohana, Chuou-ku, Chiba, Chiba 260-8670, Japan
| | - Masaomi Iyo
- Department of Psychiatry, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuou-ku, Chiba, Chiba 260-8670, Japan
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Crawford CA, Teran A, Ramirez GI, Katz CG, Mohd-Yusof A, Eaton SE, Real V, McDougall SA. Age-dependent effects of dopamine receptor inactivation on cocaine-induced behaviors in male rats: Evidence of dorsal striatal D2 receptor supersensitivity. J Neurosci Res 2019; 97:1546-1558. [PMID: 31304635 DOI: 10.1002/jnr.24491] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 06/09/2019] [Accepted: 06/14/2019] [Indexed: 12/21/2022]
Abstract
N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ), which irreversibly inactivates dopamine (DA) receptors, causes pronounced age-dependent behavioral effects in rats. For example, EEDQ either augments or does not affect the DA agonist-induced locomotor activity of preweanling rats while attenuating the locomotion of adolescent and adult rats. The twofold purpose of this study was to determine whether EEDQ would: (a) potentiate or attenuate the cocaine-induced locomotor activity of preweanling, adolescent, and adult rats; and (b) alter the sensitivity of surviving D2 receptors. Rats were treated with vehicle or EEDQ (2.5 or 7.5 mg/kg) on postnatal day (PD) 17, PD 39, and PD 84. In the behavioral experiments, saline- or cocaine-induced locomotion was assessed 24 hr later. In the biochemical experiments, dorsal striatal samples were taken 24 hr after vehicle or EEDQ treatment and later assayed for NPA-stimulated GTPγS receptor binding, G protein-coupled receptor kinase 6 (GRK6), and β-arrestin-2 (ARRB2). GTPγS binding is a direct measure of ligand-induced G protein activation, while GRK6 and ARRB2 modulate the internalization and desensitization of D2 receptors. Results showed that EEDQ potentiated the locomotor activity of preweanling rats, while attenuating the locomotion of older rats. NPA-stimulated GTPγS binding was elevated in EEDQ-treated preweanling rats, relative to adults, indicating enhanced functional coupling between the G protein and receptor. EEDQ also reduced ARRB2 levels in all age groups, which is indicative of increased D2 receptor sensitivity. In sum, the present results support the hypothesis that D2 receptor supersensitivity is a critical factor mediating the locomotor potentiating effects of EEDQ in cocaine-treated preweanling rats.
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Affiliation(s)
- Cynthia A Crawford
- Department of Psychology, California State University, San Bernardino, California
| | - Angie Teran
- Department of Psychology, California State University, San Bernardino, California
| | - Goretti I Ramirez
- Department of Psychology, California State University, San Bernardino, California
| | - Caitlin G Katz
- Department of Psychology, California State University, San Bernardino, California
| | - Alena Mohd-Yusof
- Department of Psychology, California State University, San Bernardino, California
| | - Shannon E Eaton
- Department of Psychology, California State University, San Bernardino, California
- Department of Psychology, University of Kentucky, Lexington, Kentucky
| | - Vanessa Real
- Department of Psychology, California State University, San Bernardino, California
| | - Sanders A McDougall
- Department of Psychology, California State University, San Bernardino, California
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Oda Y, Fujita Y, Oishi K, Nakata Y, Takase M, Niitsu T, Kanahara N, Shirayama Y, Hashimoto K, Iyo M. Alterations in glutamatergic signaling in the brain of dopamine supersensitivity psychosis and non-supersensitivity psychosis model rats. Psychopharmacology (Berl) 2017; 234:3027-3036. [PMID: 28744562 DOI: 10.1007/s00213-017-4695-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 07/03/2017] [Indexed: 12/27/2022]
Abstract
BACKGROUND The long-term administration of antipsychotics is known to induce dopamine supersensitivity psychosis (DSP). Although the mechanism of DSP involves mainly a compensatory upregulation of dopamine D2 receptors, the precise mechanisms underlying DSP are unknown. It is known that glutamatergic signaling plays a key role in psychosis. We thus conducted this study to investigate whether glutamatergic signaling plays a role in the development of DSP. METHODS Haloperidol (0.75 mg/kg/day for 14 days) or vehicle was administered to rats via osmotic mini-pump. Haloperidol-treated rats were divided into groups of DSP rats and non-DSP rats based on locomotion data. Tissue levels of glutamate, glutamine, glycine, L-serine, D-serine, and GABA and the protein expressions of N-methyl-D-aspartate receptors (NMDAR), glutamic acid decarboxylase (GAD), and serine hydroxymethyltransferase (SHMT) in the rat brain regions were examined. RESULTS In the DSP rats, the ratio of GABA to glutamate was significantly increased. In addition, the ratio of L-serine to glycine was increased. The striatal expressions of GAD and SHMT2 in the DSP rats were significantly increased. In contrast, the striatal expression of NMDAR2B in the non-DSP rats was significantly decreased. CONCLUSIONS The present study suggests that glutamatergic signaling is relatively decreased to GABA in DSP rats. Our results also showed that excessive doses of haloperidol can induce striatal NMDAR hypofunction in non-DSP rats, which could prevent the formation of tardive dyskinesia but cause treatment resistance. In view of the need for therapeutic strategies for treatment-resistant schizophrenia, further research exploring our present findings is necessary.
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Affiliation(s)
- Yasunori Oda
- Department of Psychiatry, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuou-ku, Chiba, Chiba, 260-8670, Japan.
| | - Yuko Fujita
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 1-8-1 Inohana, Chuou-ku, Chiba, Chiba, 260-8670, Japan
| | - Kengo Oishi
- Department of Psychiatry, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuou-ku, Chiba, Chiba, 260-8670, Japan
| | - Yusuke Nakata
- Department of Psychiatry, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuou-ku, Chiba, Chiba, 260-8670, Japan
| | - Masayuki Takase
- Department of Psychiatry, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuou-ku, Chiba, Chiba, 260-8670, Japan
| | - Tomihisa Niitsu
- Department of Psychiatry, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuou-ku, Chiba, Chiba, 260-8670, Japan
| | - Nobuhisa Kanahara
- Division of Medical Treatment and Rehabilitation, Chiba University Center for Forensic Mental Health, 1-8-1 Inohana, Chuou-ku, Chiba, Chiba, 260-8670, Japan
| | - Yukihiko Shirayama
- Department of Psychiatry, Teikyo University Chiba Medical Center, 3426-3 Anesaki, Ichihara, Chiba, 290-0111, Japan
| | - Kenji Hashimoto
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 1-8-1 Inohana, Chuou-ku, Chiba, Chiba, 260-8670, Japan
| | - Masaomi Iyo
- Department of Psychiatry, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuou-ku, Chiba, Chiba, 260-8670, Japan
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Kubota M, Nagashima T, Takano H, Kodaka F, Fujiwara H, Takahata K, Moriguchi S, Kimura Y, Higuchi M, Okubo Y, Takahashi H, Ito H, Suhara T. Affinity States of Striatal Dopamine D2 Receptors in Antipsychotic-Free Patients with Schizophrenia. Int J Neuropsychopharmacol 2017; 20:928-935. [PMID: 29016872 PMCID: PMC5737675 DOI: 10.1093/ijnp/pyx063] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 07/19/2017] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Dopamine D2 receptors are reported to have high-affinity (D2High) and low-affinity (D2Low) states. Although an increased proportion of D2High has been demonstrated in animal models of schizophrenia, few clinical studies have investigated this alteration of D2High in schizophrenia in vivo. METHODS Eleven patients with schizophrenia, including 10 antipsychotic-naive and 1 antipsychotic-free individuals, and 17 healthy controls were investigated. Psychopathology was assessed by Positive and Negative Syndrome Scale, and a 5-factor model was used. Two radioligands, [11C]raclopride and [11C]MNPA, were employed to quantify total dopamine D2 receptor and D2High, respectively, in the striatum by measuring their binding potentials. Binding potential values of [11C]raclopride and [11C]MNPA and the binding potential ratio of [11C]MNPA to [11C]raclopride in the striatal subregions were statistically compared between the 2 diagnostic groups using multivariate analysis of covariance controlling for age, gender, and smoking. Correlations between binding potential and Positive and Negative Syndrome Scale scores were also examined. RESULTS Multivariate analysis of covariance demonstrated a significant effect of diagnosis (schizophrenia and control) on the binding potential ratio (P=.018), although the effects of diagnosis on binding potential values obtained with either [11C]raclopride or [11C]MNPA were nonsignificant. Posthoc test showed that the binding potential ratio was significantly higher in the putamen of patients (P=.017). The Positive and Negative Syndrome Scale "depressed" factor in patients was positively correlated with binding potential values of both ligands in the caudate. CONCLUSIONS The present study indicates the possibilities of: (1) a higher proportion of D2High in the putamen despite unaltered amounts of total dopamine D2 receptors; and (2) associations between depressive symptoms and amounts of caudate dopamine D2 receptors in patients with schizophrenia.
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Affiliation(s)
- Manabu Kubota
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Kubota, Nagashima, Takano, Kodaka, Fujiwara, Moriguchi, Kimura, Higuchi, Takahashi, Ito, and Suhara); Department of Psychiatry, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Psychiatry, Jikei University School of Medicine, Tokyo, Japan (Dr Kodaka); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura); Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan (Dr Okubo); Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan (Dr Takahashi); Department of Radiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (Dr Ito)
| | - Tomohisa Nagashima
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Kubota, Nagashima, Takano, Kodaka, Fujiwara, Moriguchi, Kimura, Higuchi, Takahashi, Ito, and Suhara); Department of Psychiatry, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Psychiatry, Jikei University School of Medicine, Tokyo, Japan (Dr Kodaka); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura); Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan (Dr Okubo); Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan (Dr Takahashi); Department of Radiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (Dr Ito)
| | - Harumasa Takano
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Kubota, Nagashima, Takano, Kodaka, Fujiwara, Moriguchi, Kimura, Higuchi, Takahashi, Ito, and Suhara); Department of Psychiatry, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Psychiatry, Jikei University School of Medicine, Tokyo, Japan (Dr Kodaka); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura); Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan (Dr Okubo); Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan (Dr Takahashi); Department of Radiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (Dr Ito)
| | - Fumitoshi Kodaka
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Kubota, Nagashima, Takano, Kodaka, Fujiwara, Moriguchi, Kimura, Higuchi, Takahashi, Ito, and Suhara); Department of Psychiatry, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Psychiatry, Jikei University School of Medicine, Tokyo, Japan (Dr Kodaka); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura); Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan (Dr Okubo); Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan (Dr Takahashi); Department of Radiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (Dr Ito)
| | - Hironobu Fujiwara
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Kubota, Nagashima, Takano, Kodaka, Fujiwara, Moriguchi, Kimura, Higuchi, Takahashi, Ito, and Suhara); Department of Psychiatry, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Psychiatry, Jikei University School of Medicine, Tokyo, Japan (Dr Kodaka); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura); Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan (Dr Okubo); Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan (Dr Takahashi); Department of Radiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (Dr Ito)
| | - Keisuke Takahata
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Kubota, Nagashima, Takano, Kodaka, Fujiwara, Moriguchi, Kimura, Higuchi, Takahashi, Ito, and Suhara); Department of Psychiatry, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Psychiatry, Jikei University School of Medicine, Tokyo, Japan (Dr Kodaka); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura); Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan (Dr Okubo); Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan (Dr Takahashi); Department of Radiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (Dr Ito)
| | - Sho Moriguchi
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Kubota, Nagashima, Takano, Kodaka, Fujiwara, Moriguchi, Kimura, Higuchi, Takahashi, Ito, and Suhara); Department of Psychiatry, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Psychiatry, Jikei University School of Medicine, Tokyo, Japan (Dr Kodaka); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura); Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan (Dr Okubo); Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan (Dr Takahashi); Department of Radiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (Dr Ito)
| | - Yasuyuki Kimura
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Kubota, Nagashima, Takano, Kodaka, Fujiwara, Moriguchi, Kimura, Higuchi, Takahashi, Ito, and Suhara); Department of Psychiatry, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Psychiatry, Jikei University School of Medicine, Tokyo, Japan (Dr Kodaka); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura); Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan (Dr Okubo); Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan (Dr Takahashi); Department of Radiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (Dr Ito)
| | - Makoto Higuchi
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Kubota, Nagashima, Takano, Kodaka, Fujiwara, Moriguchi, Kimura, Higuchi, Takahashi, Ito, and Suhara); Department of Psychiatry, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Psychiatry, Jikei University School of Medicine, Tokyo, Japan (Dr Kodaka); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura); Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan (Dr Okubo); Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan (Dr Takahashi); Department of Radiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (Dr Ito)
| | - Yoshiro Okubo
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Kubota, Nagashima, Takano, Kodaka, Fujiwara, Moriguchi, Kimura, Higuchi, Takahashi, Ito, and Suhara); Department of Psychiatry, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Psychiatry, Jikei University School of Medicine, Tokyo, Japan (Dr Kodaka); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura); Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan (Dr Okubo); Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan (Dr Takahashi); Department of Radiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (Dr Ito)
| | - Hidehiko Takahashi
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Kubota, Nagashima, Takano, Kodaka, Fujiwara, Moriguchi, Kimura, Higuchi, Takahashi, Ito, and Suhara); Department of Psychiatry, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Psychiatry, Jikei University School of Medicine, Tokyo, Japan (Dr Kodaka); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura); Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan (Dr Okubo); Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan (Dr Takahashi); Department of Radiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (Dr Ito)
| | - Hiroshi Ito
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Kubota, Nagashima, Takano, Kodaka, Fujiwara, Moriguchi, Kimura, Higuchi, Takahashi, Ito, and Suhara); Department of Psychiatry, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Psychiatry, Jikei University School of Medicine, Tokyo, Japan (Dr Kodaka); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura); Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan (Dr Okubo); Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan (Dr Takahashi); Department of Radiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (Dr Ito)
| | - Tetsuya Suhara
- Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (Drs Kubota, Nagashima, Takano, Kodaka, Fujiwara, Moriguchi, Kimura, Higuchi, Takahashi, Ito, and Suhara); Department of Psychiatry, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan (Dr Takano); Department of Psychiatry, Jikei University School of Medicine, Tokyo, Japan (Dr Kodaka); Department of Clinical and Experimental Neuroimaging, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan (Dr Kimura); Department of Neuropsychiatry, Nippon Medical School, Tokyo, Japan (Dr Okubo); Department of Psychiatry, Graduate School of Medicine, Kyoto University, Kyoto, Japan (Dr Takahashi); Department of Radiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (Dr Ito).,Correspondence: Tetsuya Suhara, MD, PhD, Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba 263–8555, Japan ()
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Su P, Lu JY, Seeman P, Liu F. Glutamate drug reduces dopamine inhibition of phosphorylation. Synapse 2015; 70:45-8. [PMID: 26583745 DOI: 10.1002/syn.21874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 11/03/2015] [Accepted: 11/04/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Ping Su
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8, Canada
| | - Justin Y Lu
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8, Canada
| | - Philip Seeman
- Department of Pharmacology, University of Toronto, Toronto, Ontario, M5T 1R8, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, M5T 1R8, Canada
| | - Fang Liu
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, M5T 1R8, Canada
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Fujioka R, Nii T, Iwaki A, Shibata A, Ito I, Kitaichi K, Nomura M, Hattori S, Takao K, Miyakawa T, Fukumaki Y. Comprehensive behavioral study of mGluR3 knockout mice: implication in schizophrenia related endophenotypes. Mol Brain 2014; 7:31. [PMID: 24758191 PMCID: PMC4021612 DOI: 10.1186/1756-6606-7-31] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2014] [Accepted: 04/15/2014] [Indexed: 11/23/2022] Open
Abstract
Background We previously performed systematic association studies of glutamate receptor gene family members with schizophrenia, and found positive associations of polymorphisms in the GRM3 (a gene of metabotropic glutamate receptor 3: mGluR3) with the disorder. Physiological roles of GRM3 in brain functions and its functional roles in the pathogenesis of schizophrenia remain to be resolved. Results We generated mGluR3 knockout (KO) mice and conducted comprehensive behavioral analyses. KO mice showed hyperactivity in the open field, light/dark transition, and 24-hour home cage monitoring tests, impaired reference memory for stressful events in the Porsolt forced swim test, impaired contextual memory in cued and contextual fear conditioning test, and impaired working memory in the T-Maze forced alternation task test. Hyperactivity and impaired working memory are known as endophenotypes of schizophrenia. We examined long-term synaptic plasticity by assessing long-term potentiation (LTP) in the CA1 region in the hippocampi of KO and wild-type (WT) mice. We observed no differences in the amplitude of LTP between the two genotypes, suggesting that mGluR3 is not essential for LTP in the CA1 region of the mouse hippocampus. As hyperactivity is typically associated with increased dopaminergic transmission, we performed in vivo microdialysis measurements of extracellular dopamine in the nucleus accumbens of KO and WT mice. We observed enhancements in the methamphetamine (MAP)-induced release of dopamine in KO mice. Conclusions These results demonstrate that a disturbance in the glutamate-dopamine interaction may be involved in the pathophysiology of schizophrenia-like behavior, such as hyperactivity in mGluR3 KO mice.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Yasuyuki Fukumaki
- Division of Human Molecular Genetics, Research Center for Genetic Information, Medical Institute of Bioregulation, Fukuoka 812-8582, Japan.
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Brisch R, Saniotis A, Wolf R, Bielau H, Bernstein HG, Steiner J, Bogerts B, Braun K, Jankowski Z, Kumaratilake J, Henneberg M, Gos T, Henneberg M, Gos T. The role of dopamine in schizophrenia from a neurobiological and evolutionary perspective: old fashioned, but still in vogue. Front Psychiatry 2014; 5:47. [PMID: 24904434 PMCID: PMC4032934 DOI: 10.3389/fpsyt.2014.00047] [Citation(s) in RCA: 178] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 04/23/2014] [Indexed: 12/12/2022] Open
Abstract
Dopamine is an inhibitory neurotransmitter involved in the pathology of schizophrenia. The revised dopamine hypothesis states that dopamine abnormalities in the mesolimbic and prefrontal brain regions exist in schizophrenia. However, recent research has indicated that glutamate, GABA, acetylcholine, and serotonin alterations are also involved in the pathology of schizophrenia. This review provides an in-depth analysis of dopamine in animal models of schizophrenia and also focuses on dopamine and cognition. Furthermore, this review provides not only an overview of dopamine receptors and the antipsychotic effects of treatments targeting them but also an outline of dopamine and its interaction with other neurochemical models of schizophrenia. The roles of dopamine in the evolution of the human brain and human mental abilities, which are affected in schizophrenia patients, are also discussed.
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Affiliation(s)
- Ralf Brisch
- Department of Forensic Medicine, Medical University of Gdańsk , Gdańsk , Poland
| | - Arthur Saniotis
- School of Medical Sciences, The University of Adelaide , Adelaide, SA , Australia ; Centre for Evolutionary Medicine, University of Zurich , Zurich , Switzerland
| | - Rainer Wolf
- Department of Psychiatry and Psychotherapy, Ruhr University Bochum , Bochum , Germany
| | - Hendrik Bielau
- Department of Psychiatry, Otto-von-Guericke-University of Magdeburg , Magdeburg , Germany
| | - Hans-Gert Bernstein
- Department of Psychiatry, Otto-von-Guericke-University of Magdeburg , Magdeburg , Germany
| | - Johann Steiner
- Department of Psychiatry, Otto-von-Guericke-University of Magdeburg , Magdeburg , Germany
| | - Bernhard Bogerts
- Department of Psychiatry, Otto-von-Guericke-University of Magdeburg , Magdeburg , Germany
| | - Katharina Braun
- Department of Zoology, Institute of Biology, Otto-von-Guericke-University of Magdeburg , Magdeburg , Germany
| | - Zbigniew Jankowski
- Department of Forensic Medicine, Medical University of Gdańsk , Gdańsk , Poland
| | - Jaliya Kumaratilake
- Biological Anthropology and Comparative Anatomy Research Unit, School of Biomedical Sciences, The University of Adelaide , Adelaide, SA , Australia
| | - Maciej Henneberg
- Biological Anthropology and Comparative Anatomy Research Unit, School of Biomedical Sciences, The University of Adelaide , Adelaide, SA , Australia
| | - Tomasz Gos
- Department of Forensic Medicine, Medical University of Gdańsk , Gdańsk , Poland
| | - Maciej Henneberg
- Biological Anthropology and Comparative Anatomy Research Unit, School of Biomedical Sciences, The University of Adelaide , Adelaide, SA , Australia
| | - Tomasz Gos
- Department of Forensic Medicine, Medical University of Gdańsk , Gdańsk , Poland
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9
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Lane TA, Boerner T, Bannerman DM, Kew JNC, Tunbridge EM, Sharp T, Harrison PJ. Decreased striatal dopamine in group II metabotropic glutamate receptor (mGlu2/mGlu3) double knockout mice. BMC Neurosci 2013; 14:102. [PMID: 24053122 PMCID: PMC3857325 DOI: 10.1186/1471-2202-14-102] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 09/17/2013] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Group II metabotropic glutamate receptors (mGlu2 and mGlu3, encoded by Grm2 and Grm3) have been the focus of attention as treatment targets for a number of psychiatric conditions. Double knockout mice lacking mGlu2 and mGlu3 (mGlu2/3-/-) show a subtle behavioural phenotype, being hypoactive under basal conditions and in response to amphetamine, and with a spatial memory deficit that depends on the arousal properties of the task. The neurochemical correlates of this profile are unknown. Here, we measured tissue levels of dopamine, 5-HT, noradrenaline and their metabolites in the striatum and frontal cortex of mGlu2/3-/- double knockout mice, using high performance liquid chromatography. We also measured the same parameters in mGlu2-/- and mGlu3-/- single knockout mice. RESULTS mGlu2/3-/-mice had reduced dopamine levels in the striatum but not in frontal cortex, compared to wild-types. In a separate cohort we replicated this deficit and, using tissue punches, found it was more prominent in the nucleus accumbens than in dorsolateral striatum. Noradrenaline, 5-HT and their metabolites were not altered in the striatum of mGlu2/3-/- mice, although the noradrenaline metabolite MHPG was increased in the cortex. In mGlu2-/- and mGlu3-/- single knockout mice we found no difference in any monoamine or metabolite, in either brain region, compared to their wild-type littermates. CONCLUSIONS Group II metabotropic glutamate receptors impact upon striatal dopamine. The effect may contribute to the behavioural phenotype of mGlu2/3-/- mice. The lack of dopaminergic alterations in mGlu2-/- and mGlu3-/- single knockout mice reveals a degree of redundancy between the two receptors. The findings support the possibility that interactions between mGlu2/3 and dopamine may be relevant to the pathophysiology and therapy of schizophrenia and other disorders.
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Affiliation(s)
- Tracy A Lane
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford OX3 7JX, UK.
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10
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Agonist high- and low-affinity states of dopamine D₂ receptors: methods of detection and clinical implications. Naunyn Schmiedebergs Arch Pharmacol 2012; 386:135-54. [PMID: 23224422 DOI: 10.1007/s00210-012-0817-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 11/22/2012] [Indexed: 01/10/2023]
Abstract
Dopamine D(2) receptors, similar to other G-protein-coupled receptors, exist in a high- and low-affinity state for agonists. Based upon a review of the methods for detecting D(2) receptor agonist high-affinity states, we discuss alterations of such states in animal models of disease and the implications of such alterations for their labelling with positron emission tomography (PET) and single-photon emission computed tomography (SPECT) tracers. The classic approach of detecting agonist high-affinity states compares agonist competition for antagonist radioligands, in most cases using [(3)H]-spiperone as the radioligand; alternative approaches and radioligands have been proposed, but their claimed advantages have not been substantiated by other investigators. In view of the advantages and disadvantages of various techniques, we critically have reviewed reported findings on the detection of D(2) receptor agonist high-affinity states in a variety of animal models. These data are compared to the less numerous findings from human in vivo studies based on PET and SPECT tracers; they are interpreted in light of the finding that D(2) receptor agonist high-affinity states under control conditions may differ between rodent and human brain. The potential advantages of agonist ligands in studies of pathophysiology and as diagnostics are being discussed.
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11
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Affiliation(s)
- Philip Seeman
- Department of Pharmacology, University of Toronto, 260 Heath Street West, Suite 605, Toronto, Ontario, Canada M5P 3L6.
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12
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Vinson PN, Conn PJ. Metabotropic glutamate receptors as therapeutic targets for schizophrenia. Neuropharmacology 2012; 62:1461-72. [PMID: 21620876 PMCID: PMC3189289 DOI: 10.1016/j.neuropharm.2011.05.005] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 05/02/2011] [Accepted: 05/08/2011] [Indexed: 01/13/2023]
Abstract
Treatment options for schizophrenia that address all symptom categories (positive, negative, and cognitive) are lacking in current therapies for this disorder. Compounds targeting the metabotropic glutamate (mGlu) receptors hold promise as a more comprehensive therapeutic alternative to typical and atypical antipsychotics and may avoid the occurrence of extrapyramidal side effects that accompany these treatments. Activation of the group II mGlu receptors (mGlu(2) and mGlu(3)) and the group I mGlu(5) are hypothesized to normalize the disruption of thalamocortical glutamatergic circuitry that results in abnormal glutamaterigic signaling in the prefrontal cortex (PFC). Agonists of mGlu(2) and mGlu(3) have demonstrated efficacy for the positive symptom group in both animal models and clinical trials with mGlu(2) being the subtype most likely responsible for the therapeutic effect. Limitations in the chemical space tolerated by the orthosteric site of the mGlu receptors has led to the pursuit of compounds that potentiate the receptor's response to glutamate by acting at less highly conserved allosteric sites. Several series of selective positive allosteric modulators (PAMs) for mGlu(2) and mGlu(5) have demonstrated efficacy in animal models used for the evaluation of antipsychotic agents. In addition, evidence from animal studies indicates that mGlu(5) PAMs hold promise for the treatment of cognitive deficits that occur in schizophrenia. Hopefully, further optimization of allosteric modulators of mGlu receptors will yield clinical candidates that will allow full evaluation of the potential efficacy of these compounds in the treatment of multiple symptom domains in schizophrenia patients in the near future.
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Affiliation(s)
- Paige N. Vinson
- Vanderbilt University Medical Center, Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Nashville, TN 37202
| | - P. Jeffrey Conn
- Vanderbilt University Medical Center, Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Nashville, TN 37202
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13
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Herman EJ, Bubser M, Conn PJ, Jones CK. Metabotropic glutamate receptors for new treatments in schizophrenia. Handb Exp Pharmacol 2012:297-365. [PMID: 23027420 DOI: 10.1007/978-3-642-25758-2_11] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Metabotropic glutamate receptors (mGluRs) represent exciting targets for the development of novel therapeutic agents for schizophrenia. Recent studies indicate that selective activation of specific mGluR subtypes may provide potential benefits for not only the positive symptoms, but also the negative symptoms and cognitive impairments observed in individuals with schizophrenia. Although optimization of traditional orthosteric agonists may still offer a feasible approach for the activation of mGluRs, important progress has been made in the discovery of novel subtype-selective allosteric ligands, including positive allosteric modulators (PAMs) of mGluR2 and mGluR5. These allosteric mGluR ligands have improved properties for clinical development and have served as key preclinical tools for a more in-depth understanding of the potential roles of these different mGluR subtypes for the treatment of schizophrenia.
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Affiliation(s)
- E J Herman
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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14
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Lin CY, Sawa A, Jaaro-Peled H. Better understanding of mechanisms of schizophrenia and bipolar disorder: from human gene expression profiles to mouse models. Neurobiol Dis 2011; 45:48-56. [PMID: 21914480 DOI: 10.1016/j.nbd.2011.08.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 08/22/2011] [Accepted: 08/26/2011] [Indexed: 01/01/2023] Open
Abstract
The molecular mechanisms of major mental illnesses, such as schizophrenia and bipolar disorder, are unclear. To address this fundamental question, many groups have studied molecular expression profiles in postmortem brains and other tissues from patients compared with those from normal controls. Development of unbiased high-throughput approaches, such as microarray, RNA-seq, and proteomics, have supported and facilitated this endeavor. In addition to genes directly involved in neuron/glia signaling, especially those encoding for synaptic proteins, genes for metabolic cascades are differentially expressed in the brains of patients with schizophrenia and bipolar disorder, compared with those from normal controls in DNA microarray studies. Here we propose the importance and usefulness of genetic mouse models in which such differentially expressed molecules are modulated. These animal models allow us to dissect the mechanisms of how such molecular changes in patient brains may play a role in neuronal circuitries and overall behavioral phenotypes. We also point out that models in which the metabolic genes are modified are obviously untested from mental illness viewpoints, suggesting the potential to re-address these models with behavioral assays and neurochemical assessments.
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Affiliation(s)
- Chi-Ying Lin
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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15
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Seeman P. All roads to schizophrenia lead to dopamine supersensitivity and elevated dopamine D2(high) receptors. CNS Neurosci Ther 2011; 17:118-32. [PMID: 20560996 DOI: 10.1111/j.1755-5949.2010.00162.x] [Citation(s) in RCA: 158] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The dopamine D2 receptor is the common target for antipsychotics, and the antipsychotic clinical doses correlate with their affinities for this receptor. Antipsychotics quickly enter the brain to occupy 60-80% of brain D2 receptors in patients (the agonist aripiprazole occupies up to 90%), with most clinical improvement occurring within a few days. The D2 receptor can exist in a state of high-affinity (D2(High) ) or in a state of low-affinity for dopamine (D2Low). AIM The present aim is to review why individuals with schizophrenia are generally supersensitive to dopamine-like drugs such as amphetamine or methyphenidate, and whether the D2(High) state is a common basis for dopamine supersensitivity in the animal models of schizophrenia. RESULTS All animal models of schizophrenia reveal elevations in D2(High) receptors. These models include brain lesions, sensitization by drugs (amphetamine, phencyclidine, cocaine, corticosterone), birth injury, social isolation, and gene deletions in pathways for NMDA, dopamine, GABA, acetylcholine, and norepinephrine. CONCLUSIONS These multiple abnormal pathways converge to a final common pathway of dopamine supersensitivity and elevated D2(High) receptors, presumably responsible for psychotic symptoms. Although antipsychotics alleviate psychosis and reverse the elevation of D2(High) receptors, long-term antipsychotics can further enhance dopamine supersensitivity in patients. Therefore, switching from a traditional antipsychotic to an agonist antipsychotic (aripiprazole) can result in psychotic signs and symptoms. Clozapine and quetiapine do not elicit parkinsonism or tardive dyskinesia because they are released from D2 within 12 to 24 h. Traditional antipsychotics remain attached to D2 receptors for days, preventing relapse, but allowing accumulation that can lead to tardive dyskinesia. Future goals include imaging D2(High) receptors and desensitizing them in early-stage psychosis.
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Affiliation(s)
- Philip Seeman
- Departments of Pharmacology and Psychiatry, University of Toronto, 260 Heath Street West, Suite 605, Toronto, Ontario, Canada M5P 3L6.
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Abstract
Growing evidence for glutamate abnormalities in schizophrenia support the development of novel antipsychotic agents targeting this system. Early studies investigating modulation of the glutamate system using glycine, D-serine and sarcosine in patients with schizophrenia have demonstrated significant effects, particularly on negative symptoms, conventionally thought to be refractory to antipsychotic drug treatment. Drugs targeting the glutamate system also have a completely different side-effect profile to dopamine D2 antagonists, with no propensity to extrapyramidal side effects, prolactinaemia or weight gain. It has been hypothesized that glutamatergic drugs may be of benefit to the 20-30% of individuals with schizophrenia who fail to show any response to dopaminergic agents, and may be particularly useful in the early stages of the illness, where they may be disease-modifying. A number of glutamatergic compounds have been reported as having promising results in phase II drug trials. If these reach the clinic, they will represent the first truly novel approach to pharmacotherapy in schizophrenia for more than 50 years.
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Affiliation(s)
- James M. Stone
- Experimental Medicine, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
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Altered distribution of mGlu2 receptors in β-amyloid-affected brain regions of Alzheimer cases and aged PS2APP mice. Brain Res 2010; 1363:180-90. [PMID: 20875805 DOI: 10.1016/j.brainres.2010.09.072] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 09/16/2010] [Accepted: 09/19/2010] [Indexed: 01/28/2023]
Abstract
Altered glutamatergic synaptic transmission is among the key events defining the course of Alzheimer's disease (AD). mGlu2 receptors, a subtype of group II metabotropic glutamate receptors, regulate (as autoreceptors) fast synaptic transmission in the CNS via the controlled release of the excitatory amino acid glutamate. Since their pharmacological manipulation in rodents has been reported to affect cognition, they are potential drug targets for AD therapy. We examined the fate of these receptors in cases of AD as well as in aging PS2APP mice--a proposed model of the disease. In vitro binding of [(3)H]LY354740, a selective group II agonist (with selective affinity for mGlu2 receptors, under the assay conditions used) and quantitative radioautography revealed a partial, but highly significant, loss of receptors in amyloid-affected discrete brain regions of AD cases and PS2APP mice. Among the mouse brain regions affected were, above all, the subiculum but also frontolateral cortex, dentate gyrus, lacunosum moleculare and caudate putamen. In AD, significant receptor losses were registered in entorhinal cortex and lacunosum moleculare (40% and 35%, respectively). These findings have implications for the development of selective ligands for symptomatic therapy in AD and for its diagnosis.
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Abstract
The antipsychotic effectiveness of chlorpromazine and haloperidol started a search for their therapeutic targets. The antipsychotic receptor target turned out to be a dopamine receptor, now cloned as the dopamine D2 receptor. The D2 receptor is the common target for antipsychotics. Antipsychotic clinical doses correlate with their affinities for this receptor. Therapeutic doses of antipsychotics occupy 60 to 80% of brain D2 receptors in patients, but aripiprazole occupies up to 90%. While antipsychotics may take up to six hours to occupy D2 receptors, much clinical improvement occurs within a few days. The receptor has high- and low-affinity states. The D2High state is functional for dopamine-like agonists such as aripiprazole. Most individuals with schizophrenia are supersensitive to dopamine. Animal models of psychosis show that a variety of risk factors, genetic and nongenetic, are associated with behavioral supersensitivity to dopamine, reflected in elevated levels of dopamine D2High receptors. Although antipsychotics such as haloperidol alleviate psychosis and reverse the elevation of D2High receptors, long-term use of traditional antipsychotics can further enhance dopamine supersensitivity in patients. Therefore, switching from a traditional antipsychotic to an agonist antipsychotic such as aripiprazole can result in the emergence of psychotic signs and symptoms. Clozapine and quetiapine do not elicit parkinsonism and rarely result in tardive dyskinesia because they are released from D2 within 12 to 24 hours. Traditional antipsychotics remain attached to D2 receptors for days, preventing relapse, but allowing accumulation that can lead to tardive dyskinesia. Future goals include imaging D2High receptors and desensitizing them in early-stage psychosis.
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Affiliation(s)
- Philip Seeman
- Pharmacology Department, Faculty of Medicine, University of Toronto, Canada.
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20
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Chan H, Paur H, Vernon AC, Zabarsky V, Datla KP, Croucher MJ, Dexter DT. Neuroprotection and Functional Recovery Associated with Decreased Microglial Activation Following Selective Activation of mGluR2/3 Receptors in a Rodent Model of Parkinson's Disease. PARKINSONS DISEASE 2010; 2010. [PMID: 20948891 PMCID: PMC2951138 DOI: 10.4061/2010/190450] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2010] [Revised: 02/24/2010] [Accepted: 03/08/2010] [Indexed: 12/21/2022]
Abstract
Clinical trials have demonstrated positive proof of efficacy of dual metabotropic glutamate receptor 2/3 (mGluR2/3) agonists in both anxiety and schizophrenia. Importantly, evidence suggests that these drugs may also be neuroprotective against glutamate excitotoxicity, implicated in the pathogenesis of Parkinson's disease (PD). However, whether this neuroprotection also translates into functional recovery is unclear. In the current study, we examined the neuroprotective efficacy of the dual mGluR2/3 agonist, 2R,4R-4-aminopyrrolidine-2,4-dicarboxylate (2R,4R-APDC), and whether this is accompanied by behavioral recovery in a rodent 6-hydroxydopamine (6-OHDA) model of PD. We now report that delayed post lesion treatment with 2R,4R-APDC (10 nmol), results in robust neuroprotection of the nigrostriatal system, which translated into functional recovery as measured by improved forelimb use asymmetry and reduced (+)-amphetamine-induced rotation compared to vehicle treated animals. Interestingly, these beneficial effects were associated with a decrease in microglial markers in the SNc, which may suggest an antiinflammatory action of this drug.
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Affiliation(s)
- Hugh Chan
- Parkinson's Disease Research Group, Faculty of Medicine, Imperial College London, 4th Floor, Burlington Danes Building, Hammersmith Hospital, Du Cane Road, W12 0NN London, UK
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21
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van den Buuse M. Modeling the positive symptoms of schizophrenia in genetically modified mice: pharmacology and methodology aspects. Schizophr Bull 2010; 36:246-70. [PMID: 19900963 PMCID: PMC2833124 DOI: 10.1093/schbul/sbp132] [Citation(s) in RCA: 275] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In recent years, there have been huge advances in the use of genetically modified mice to study pathophysiological mechanisms involved in schizophrenia. This has allowed rapid progress in our understanding of the role of several proposed gene mechanisms in schizophrenia, and yet this research has also revealed how much still remains unresolved. Behavioral studies in genetically modified mice are reviewed with special emphasis on modeling psychotic-like behavior. I will particularly focus on observations on locomotor hyperactivity and disruptions of prepulse inhibition (PPI). Recommendations are included to address pharmacological and methodological aspects in future studies. Mouse models of dopaminergic and glutamatergic dysfunction are then discussed, reflecting the most important and widely studied neurotransmitter systems in schizophrenia. Subsequently, psychosis-like behavior in mice with modifications in the most widely studied schizophrenia susceptibility genes is reviewed. Taken together, the available studies reveal a wealth of available data which have already provided crucial new insight and mechanistic clues which could lead to new treatments or even prevention strategies for schizophrenia.
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Affiliation(s)
- Maarten van den Buuse
- Mental Health Research Institute of Victoria, Parkville, Melbourne, Victoria 3052, Australia.
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22
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Cherlyn SYT, Woon PS, Liu JJ, Ong WY, Tsai GC, Sim K. Genetic association studies of glutamate, GABA and related genes in schizophrenia and bipolar disorder: a decade of advance. Neurosci Biobehav Rev 2010; 34:958-77. [PMID: 20060416 DOI: 10.1016/j.neubiorev.2010.01.002] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 01/01/2010] [Accepted: 01/04/2010] [Indexed: 12/31/2022]
Abstract
Schizophrenia (SZ) and bipolar disorder (BD) are debilitating neurobehavioural disorders likely influenced by genetic and non-genetic factors and which can be seen as complex disorders of synaptic neurotransmission. The glutamatergic and GABAergic neurotransmission systems have been implicated in both diseases and we have reviewed extensive literature over a decade for evidence to support the association of glutamate and GABA genes in SZ and BD. Candidate-gene based population and family association studies have implicated some ionotrophic glutamate receptor genes (GRIN1, GRIN2A, GRIN2B and GRIK3), metabotropic glutamate receptor genes (such as GRM3), the G72/G30 locus and GABAergic genes (e.g. GAD1 and GABRB2) in both illnesses to varying degrees, but further replication studies are needed to validate these results. There is at present no consensus on specific single nucleotide polymorphisms or haplotypes associated with the particular candidate gene loci in these illnesses. The genetic architecture of glutamate systems in bipolar disorder need to be better studied in view of recent data suggesting an overlap in the genetic aetiology of SZ and BD. There is a pressing need to integrate research platforms in genomics, epistatic models, proteomics, metabolomics, neuroimaging technology and translational studies in order to allow a more integrated understanding of glutamate and GABAergic signalling processes and aberrations in SZ and BD as well as their relationships with clinical presentations and treatment progress over time.
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Affiliation(s)
- Suat Ying Tan Cherlyn
- Institute of Mental Health/Woodbridge Hospital, 10 Buangkok View, Singapore 539747, Singapore
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23
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Seeman P, Guan HC. Glutamate agonist LY404,039 for treating schizophrenia has affinity for the dopamine D2(High) receptor. Synapse 2009; 63:935-9. [PMID: 19588471 DOI: 10.1002/syn.20704] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The glutamate agonist LY404,039 has been used to treat schizophrenia. Because all currently used antipsychotics act on dopamine receptors, it was decided to examine whether this glutamate agonist also had an affinity for dopamine D2 receptors in vitro. The present data show that LY404,039 inhibited the binding of [3H]domperidone and [3H]+PHNO by 15.5 +/- 1.5% to the high-affinity state, D2(High), of cloned dopamine D2(Long) receptors and rat striatal tissue with dissociation constants of between 8.2 and 12.6 nM. This high-affinity component of LY404,039 on the binding of [3H]domperidone was inhibited by the presence of guanine nucleotide, indicating an agonist action of the drug at D2(High). LY404,039 also stimulated the incorporation of [35S]GTP-gamma-S into D2(Long) receptors (EC50% = 80 +/- 15 nM) over the same range of concentrations as occurred for the inhibition of [3H]domperidone by LY404,039 at D2(High) (IC50%(High) = 50 +/- 10 nM). A possible clinical antipsychotic action of LY404,039 may depend on the combined stimulation of glutamate receptors and a partial dopamine agonist action that would interfere with neurotransmission at D2(High) receptors.
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Affiliation(s)
- Philip Seeman
- Department of Pharmacology, Medical Science Building, University of Toronto, Toronto, Ontario, Canada M5S 1A8.
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24
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Seeman P, Guan HC. Glutamate agonists for treating schizophrenia have affinity for dopamine D2Highand D3 receptors. Synapse 2009; 63:705-9. [DOI: 10.1002/syn.20673] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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