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Ralph LT, Georgiou J, Collingridge GL, Tidball P. Sex-dependence of synaptic depression induced by activation of metabotropic glutamate receptors in rat hippocampus. Brain Neurosci Adv 2024; 8:23982128231223579. [PMID: 38298523 PMCID: PMC10826376 DOI: 10.1177/23982128231223579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 12/04/2023] [Indexed: 02/02/2024] Open
Abstract
The modulation of synaptic efficacy by group I metabotropic glutamate receptors is dysregulated in several neurodevelopmental and neurodegenerative disorders impacting cognitive function. The progression and severity of these and other disorders are affected by biological sex, and differences in metabotropic glutamate receptor signalling have been implicated in this effect. In this study, we have examined whether there are any sex-dependent differences in a form of long-term depression of synaptic responses that is triggered by application of the group I metabotropic glutamate receptor agonist 3,5-dihydroxyphenylglycine (DHPG). We studied DHPG-induced long-term depression at the Schaffer collateral-commissural pathway in area CA1 of hippocampal slices prepared from three separate age groups of Sprague Dawley rats. In both juvenile (2-week-old) and young adult (3-month-old) rats, there were no differences between sexes in the magnitude of long-term depression. However, in older adult (>1-year-old) rats, DHPG-induced long-term depression was greater in males. In contrast, there were no differences between sexes with respect to basal synaptic transmission or paired-pulse facilitation in any age group. The specific enhancement of metabotropic glutamate receptor-dependent long-term depression in older adult males, but not females, reinforces the importance of considering sex as a factor in the study and treatment of brain disorders.
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Affiliation(s)
- Liam T. Ralph
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, ON, Canada
- TANZ Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
| | - John Georgiou
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, ON, Canada
- TANZ Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
| | - Graham L. Collingridge
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, ON, Canada
- TANZ Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
| | - Patrick Tidball
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, ON, Canada
- TANZ Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
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Sanderson TM, Ralph LT, Amici M, Ng AN, Kaang BK, Zhuo M, Kim SJ, Georgiou J, Collingridge GL. Selective Recruitment of Presynaptic and Postsynaptic Forms of mGluR-LTD. Front Synaptic Neurosci 2022; 14:857675. [PMID: 35615440 PMCID: PMC9126322 DOI: 10.3389/fnsyn.2022.857675] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 04/20/2022] [Indexed: 12/03/2022] Open
Abstract
In area CA1 of the hippocampus, long-term depression (LTD) can be induced by activating group I metabotropic glutamate receptors (mGluRs), with the selective agonist DHPG. There is evidence that mGluR-LTD can be expressed by either a decrease in the probability of neurotransmitter release [P(r)] or by a change in postsynaptic AMPA receptor number. However, what determines the locus of expression is unknown. We investigated the expression mechanisms of mGluR-LTD using either a low (30 μM) or a high (100 μM) concentration of (RS)-DHPG. We found that 30 μM DHPG generated presynaptic LTD that required the co-activation of NMDA receptors, whereas 100 μM DHPG resulted in postsynaptic LTD that was independent of the activation of NMDA receptors. We found that both forms of LTD occur at the same synapses and that these may constitute the population with the lowest basal P(r). Our results reveal an unexpected complexity to mGluR-mediated synaptic plasticity in the hippocampus.
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Affiliation(s)
- Thomas M. Sanderson
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, ON, Canada
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, South Korea
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Liam T. Ralph
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, ON, Canada
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Mascia Amici
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Ai Na Ng
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Bong-Kiun Kaang
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
| | - Min Zhuo
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Sang Jeong Kim
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, South Korea
| | - John Georgiou
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, ON, Canada
| | - Graham L. Collingridge
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, ON, Canada
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
- *Correspondence: Graham L. Collingridge,
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