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Price R, Salavati B, Graff-Guerrero A, Blumberger DM, Mulsant BH, Daskalakis ZJ, Rajji TK. Effects of antipsychotic D2 antagonists on long-term potentiation in animals and implications for human studies. Prog Neuropsychopharmacol Biol Psychiatry 2014; 54:83-91. [PMID: 24819820 PMCID: PMC4138225 DOI: 10.1016/j.pnpbp.2014.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 04/29/2014] [Accepted: 05/01/2014] [Indexed: 10/25/2022]
Abstract
In people with schizophrenia, cognitive abilities - including memory - are strongly associated with functional outcome. Long-term potentiation (LTP) is a form of neuroplasticity that is believed to be the physiological basis for memory. It has been postulated that antipsychotic medication can impair long-term potentiation and cognition by altering dopaminergic transmission. Thus, a systematic review was performed in order to assess the relationship between antipsychotics and D2 antagonists on long-term potentiation. The majority of studies on LTP and antipsychotics have found that acute administration of antipsychotics was associated with impairments in LTP in wild-type animals. In contrast, chronic administration and acute antipsychotics in animal models of schizophrenia were not. Typical and atypical antipsychotics and other D2 antagonists behaved similarly, with the exception of clozapine and olanzapine. Clozapine caused potentiation independent of tetanization, while olanzapine facilitated tetanus-induced potentiation. These studies are limited in their ability to model the effects of antipsychotics in patients with schizophrenia as they were largely performed in wild-type animals as opposed to humans with schizophrenia, and assessed after acute rather than chronic treatment. Further studies using patients with schizophrenia receiving chronic antipsychotic treatment are needed to better understand the effects of these medications in this population.
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Affiliation(s)
- Rae Price
- Institute of Medical Science, Faculty of Medicine, University of Toronto,Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto
| | - Bahar Salavati
- Institute of Medical Science, Faculty of Medicine, University of Toronto,Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto
| | - Ariel Graff-Guerrero
- Institute of Medical Science, Faculty of Medicine, University of Toronto,Department of Psychiatry, Faculty of Medicine, University of Toronto,Geriatric Psychiatry Division, Centre for Addiction and Mental Health, Toronto,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto
| | - Daniel M. Blumberger
- Institute of Medical Science, Faculty of Medicine, University of Toronto,Department of Psychiatry, Faculty of Medicine, University of Toronto,Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto,Geriatric Psychiatry Division, Centre for Addiction and Mental Health, Toronto,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto
| | - Benoit H. Mulsant
- Institute of Medical Science, Faculty of Medicine, University of Toronto,Department of Psychiatry, Faculty of Medicine, University of Toronto,Geriatric Psychiatry Division, Centre for Addiction and Mental Health, Toronto,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto
| | - Zafiris J. Daskalakis
- Institute of Medical Science, Faculty of Medicine, University of Toronto,Department of Psychiatry, Faculty of Medicine, University of Toronto,Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto
| | - Tarek K. Rajji
- Institute of Medical Science, Faculty of Medicine, University of Toronto,Department of Psychiatry, Faculty of Medicine, University of Toronto,Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto,Geriatric Psychiatry Division, Centre for Addiction and Mental Health, Toronto,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto,Corresponding author: 80 Workman Way, Room 6312, Toronto, Ontario, Canada M6J 1H4. Phone: +1 416 535 8501 x 33661. Fax: +1 416 583 1307.
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Kubota T, Jibiki I, Ishikawa A, Kawamura T, Kurokawa S, Wang M. Increase in extracellular dopamine levels during clozapine-induced potentiation in the hippocampal dentate gyrus of chronically prepared rabbits. Can J Physiol Pharmacol 2008; 86:249-56. [DOI: 10.1139/y08-036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously found that 20 mg/kg clozapine i.p. potentiated the excitatory synaptic responses elicited in the dentate gyrus by single electrical stimulation of the perforant path in chronically prepared rabbits. We called this phenomenon clozapine-induced potentiation and proved that it was an NMDA receptor-mediated event. This potentiation is presumably related to clozapine’s clinical effect on negative symptoms and cognitive dysfunctions in schizophrenia. In the present study, to investigate the mechanisms underlying clozapine-induced potentiation, we examined whether extracellular dopamine and 5-HT levels changed during the potentiation by using a microdialysis technique in the dentate gyrus. The extracellular concentrations of dopamine and 5-HT levels were measured every 5 min during all experiments. Extracellular 5-HT levels did not change, but dopamine levels eventually increased significantly during clozapine-induced potentiation. The increase in the dopamine levels occurred almost simultaneously with the induction of clozapine-induced potentiation. These results suggest that clozapine-induced potentiation is at least partly attributable to a dopamine-mediated potentiation of excitatory synaptic transmission. The present study implies that such phenomena occur also in the perforant path–dentate gyrus pathway.
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Affiliation(s)
- Takashi Kubota
- Department of Neuropsychiatry, Kanazawa Medical University, Uchinada-Machi, Kahoku-gun, Ishikawa 920-0293, Japan
- Department of Neuropsychiatry, St. Marianna University School of Medicine, Kawasaki, Tokyo, Japan
- Department of Psychiatry and Psychology, China Medical University, Shinyou, China
| | - Itsuki Jibiki
- Department of Neuropsychiatry, Kanazawa Medical University, Uchinada-Machi, Kahoku-gun, Ishikawa 920-0293, Japan
- Department of Neuropsychiatry, St. Marianna University School of Medicine, Kawasaki, Tokyo, Japan
- Department of Psychiatry and Psychology, China Medical University, Shinyou, China
| | - Akira Ishikawa
- Department of Neuropsychiatry, Kanazawa Medical University, Uchinada-Machi, Kahoku-gun, Ishikawa 920-0293, Japan
- Department of Neuropsychiatry, St. Marianna University School of Medicine, Kawasaki, Tokyo, Japan
- Department of Psychiatry and Psychology, China Medical University, Shinyou, China
| | - Tomomi Kawamura
- Department of Neuropsychiatry, Kanazawa Medical University, Uchinada-Machi, Kahoku-gun, Ishikawa 920-0293, Japan
- Department of Neuropsychiatry, St. Marianna University School of Medicine, Kawasaki, Tokyo, Japan
- Department of Psychiatry and Psychology, China Medical University, Shinyou, China
| | - Sonoko Kurokawa
- Department of Neuropsychiatry, Kanazawa Medical University, Uchinada-Machi, Kahoku-gun, Ishikawa 920-0293, Japan
- Department of Neuropsychiatry, St. Marianna University School of Medicine, Kawasaki, Tokyo, Japan
- Department of Psychiatry and Psychology, China Medical University, Shinyou, China
| | - Man Wang
- Department of Neuropsychiatry, Kanazawa Medical University, Uchinada-Machi, Kahoku-gun, Ishikawa 920-0293, Japan
- Department of Neuropsychiatry, St. Marianna University School of Medicine, Kawasaki, Tokyo, Japan
- Department of Psychiatry and Psychology, China Medical University, Shinyou, China
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