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Tenorio-Lopes L, Henry MS, Marques D, Tremblay MÈ, Drolet G, Bretzner F, Kinkead R. Neonatal maternal separation opposes the facilitatory effect of castration on the respiratory response to hypercapnia of the adult male rat: Evidence for the involvement of the medial amygdala. J Neuroendocrinol 2017; 29. [PMID: 29063642 DOI: 10.1111/jne.12550] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 10/10/2017] [Accepted: 10/11/2017] [Indexed: 01/09/2023]
Abstract
Respiratory manifestations of panic disorder (PD) include a greater respiratory instability and enhanced responsiveness to CO2 compared to normal individuals. Although the prevalence of PD is approximately three times greater in women compared to men, the origins of this sexual dimorphism remain poorly understood. Similar to PD patients, adult female rats previously subjected to neonatal maternal separation (NMS) show an increase in their ventilatory response to CO2 . Because this effect of NMS is not observed in males, we hypothesised that testosterone prevents NMS-induced hyper-responsiveness to CO2 . Pups subjected to NMS were placed in an incubator for 3 h d-1 from postnatal days 3-12. Control pups remained undisturbed. At adulthood (8-10 weeks of age), rats were then subjected either to sham surgery or castration. Fourteen days later, breathing was measured at rest (room air) and during acute exposure to hypercapnia (5 and 10% CO2 for 10 minutes each) using plethysmography. To gain insight into the mechanisms involved, c-fos expression was used as an indicator of neuronal activation. Brains were collected following air or CO2 exposure for quantification of c-fos positive cells by immunohistochemistry in selected regions, including the paraventricular nucleus of the hypothalamus, the dorsomedial hypothalamus and the amygdalar complex. Castration produced a 100% increase of hyperventilatory response to 10% CO2 in control rats. Unexpectedly, castration had no effect on the hyperventilatory response of NMS rats. The intensity of the hypercapnic response was inversely correlated with c-fos expression in the medial amygdala. We conclude that testosterone prevents the hyper-responsiveness to CO2 , whereas NMS attenuates sensitivity to hormone withdrawal. We propose that an inhibitory influence from the medial amygdala contributes to this effect.
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Affiliation(s)
- L Tenorio-Lopes
- Department of Pediatrics, Centre de Recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec, Université Laval, Québec, QC, Canada
| | - M S Henry
- Department of Molecular Medicine, Centre de Recherche du CHU de Québec-Université Laval, Axe Neurosciences, Université Laval, Québec, QC, Canada
| | - D Marques
- Departamento de Morfologia e Fisiologia Animal Fac. de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Jaboticabal, Brazil
| | - M-È Tremblay
- Department of Molecular Medicine, Centre de Recherche du CHU de Québec-Université Laval, Axe Neurosciences, Université Laval, Québec, QC, Canada
| | - G Drolet
- Department of Molecular Medicine, Centre de Recherche du CHU de Québec-Université Laval, Axe Neurosciences, Université Laval, Québec, QC, Canada
| | - F Bretzner
- Department of Molecular Medicine, Centre de Recherche du CHU de Québec-Université Laval, Axe Neurosciences, Université Laval, Québec, QC, Canada
| | - R Kinkead
- Department of Pediatrics, Centre de Recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec, Université Laval, Québec, QC, Canada
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Sipe GO, Lowery RL, Tremblay MÈ, Kelly EA, Lamantia CE, Majewska AK. Microglial P2Y12 is necessary for synaptic plasticity in mouse visual cortex. Nat Commun 2016; 7:10905. [PMID: 26948129 PMCID: PMC4786684 DOI: 10.1038/ncomms10905] [Citation(s) in RCA: 321] [Impact Index Per Article: 40.1] [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: 10/28/2015] [Accepted: 02/01/2016] [Indexed: 12/19/2022] Open
Abstract
Microglia are the resident immune cells of the brain. Increasingly, they are recognized as important mediators of normal neurophysiology, particularly during early development. Here we demonstrate that microglia are critical for ocular dominance plasticity. During the visual critical period, closure of one eye elicits changes in the structure and function of connections underlying binocular responses of neurons in the visual cortex. We find that microglia respond to monocular deprivation during the critical period, altering their morphology, motility and phagocytic behaviour as well as interactions with synapses. To explore the underlying mechanism, we focused on the P2Y12 purinergic receptor, which is selectively expressed in non-activated microglia and mediates process motility during early injury responses. We find that disrupting this receptor alters the microglial response to monocular deprivation and abrogates ocular dominance plasticity. These results suggest that microglia actively contribute to experience-dependent plasticity in the adolescent brain. Microglia play key roles during early neurodevelopment. Here the authors show that microglia are important mediators of ocular dominance plasticity (ODP). Microglia respond to monocular deprivation during the visual critical period, and disrupting microglial P2Y12 purinergic receptor abrogates ODP.
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Affiliation(s)
- G O Sipe
- Department of Neuroscience, University of Rochester, 601 Elmwood Avenue, box 603, Rochester, New York 14642, USA.,Neuroscience Graduate Program, University of Rochester, 601 Elmwood Avenue, box 603, Rochester, New York 14642, USA
| | - R L Lowery
- Department of Neuroscience, University of Rochester, 601 Elmwood Avenue, box 603, Rochester, New York 14642, USA.,Neuroscience Graduate Program, University of Rochester, 601 Elmwood Avenue, box 603, Rochester, New York 14642, USA
| | - M-È Tremblay
- Department of Neuroscience, University of Rochester, 601 Elmwood Avenue, box 603, Rochester, New York 14642, USA
| | - E A Kelly
- Department of Neuroscience, University of Rochester, 601 Elmwood Avenue, box 603, Rochester, New York 14642, USA
| | - C E Lamantia
- Department of Neuroscience, University of Rochester, 601 Elmwood Avenue, box 603, Rochester, New York 14642, USA
| | - A K Majewska
- Department of Neuroscience, University of Rochester, 601 Elmwood Avenue, box 603, Rochester, New York 14642, USA.,Neuroscience Graduate Program, University of Rochester, 601 Elmwood Avenue, box 603, Rochester, New York 14642, USA
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