1
|
Conde SV, Polotsky VY, Joseph V, Kinkead R. On the origins of sleep disordered breathing, cardiorespiratory and metabolic dysfunction: which came first, the chicken or the egg? J Physiol 2023; 601:5509-5525. [PMID: 36988138 PMCID: PMC10539476 DOI: 10.1113/jp284113] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 03/08/2023] [Indexed: 03/30/2023] Open
Abstract
Sleep disordered breathing (SDB) is a complex, sex specific and highly heterogeneous group of respiratory disorders. Nevertheless, sleep fragmentation and repeated fluctuations of arterial blood gases for several hours per night are at the core of the problem; together, they impose significant stress to the organism with deleterious consequences on physical and mental health. SDB increases the risk of obesity, diabetes, depression and anxiety disorders; however, the same health issues are risk factors for SDB. So, which came first, the chicken or the egg? What causes the appearance of the first significant apnoeic events during sleep? These are important questions because although moderate to severe SDB affects ∼500 million adults globally, we still have a poor understanding of the origins of the disease, and the main treatments (and animal models) focus on the symptoms rather than the cause. Because obesity, metabolic dysfunction and stress-related neurological disorders generally appear progressively, we discuss how the development of these diseases can lead to specific anatomical and non-anatomical traits of SDB in males and females while considering the impacts of sex steroids. In light of the growing evidence indicating that the carotid bodies are important sensors of key metabolic and endocrine signals associated with stress and dysmetabolism, we propose that these organs play a key role in the process.
Collapse
Affiliation(s)
- Silvia V. Conde
- NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Vsevolod Y Polotsky
- Department of Anesthesiology and Critical Care Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Vincent Joseph
- Département de Pédiatrie, Université Laval & Research Center of the Québec Heart and Lung Institute, Québec, QC. Canada
| | - Richard Kinkead
- Département de Pédiatrie, Université Laval & Research Center of the Québec Heart and Lung Institute, Québec, QC. Canada
| |
Collapse
|
2
|
Kinkead R, Ambrozio-Marques D, Fournier S, Gagnon M, Guay LM. Estrogens, age, and, neonatal stress: panic disorders and novel views on the contribution of non-medullary structures to respiratory control and CO 2 responses. Front Physiol 2023; 14:1183933. [PMID: 37265841 PMCID: PMC10229816 DOI: 10.3389/fphys.2023.1183933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 04/21/2023] [Indexed: 06/03/2023] Open
Abstract
CO2 is a fundamental component of living matter. This chemical signal requires close monitoring to ensure proper match between metabolic production and elimination by lung ventilation. Besides ventilatory adjustments, CO2 can also trigger innate behavioral and physiological responses associated with fear and escape but the changes in brain CO2/pH required to induce ventilatory adjustments are generally lower than those evoking fear and escape. However, for patients suffering from panic disorder (PD), the thresholds for CO2-evoked hyperventilation, fear and escape are reduced and the magnitude of those reactions are excessive. To explain these clinical observations, Klein proposed the false suffocation alarm hypothesis which states that many spontaneous panics occur when the brain's suffocation monitor erroneously signals a lack of useful air, thereby maladaptively triggering an evolved suffocation alarm system. After 30 years of basic and clinical research, it is now well established that anomalies in respiratory control (including the CO2 sensing system) are key to PD. Here, we explore how a stress-related affective disorder such as PD can disrupt respiratory control. We discuss rodent models of PD as the concepts emerging from this research has influenced our comprehension of the CO2 chemosensitivity network, especially structure that are not located in the medulla, and how factors such as stress and biological sex modulate its functionality. Thus, elucidating why hormonal fluctuations can lead to excessive responsiveness to CO2 offers a unique opportunity to gain insights into the neuroendocrine mechanisms regulating this key aspect of respiratory control and the pathophysiology of respiratory manifestations of PD.
Collapse
|
3
|
Beyeler SA, Naidoo R, Morrison NR, McDonald EA, Albarrán D, Huxtable AG. Maternal opioids age-dependently impair neonatal respiratory control networks. Front Physiol 2023; 14:1109754. [PMID: 37008014 PMCID: PMC10060555 DOI: 10.3389/fphys.2023.1109754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 02/28/2023] [Indexed: 03/18/2023] Open
Abstract
Infants exposed to opioids in utero are an increasing clinical population and these infants are often diagnosed with Neonatal Abstinence Syndrome (NAS). Infants with NAS have diverse negative health consequences, including respiratory distress. However, many factors contribute to NAS, confounding the ability to understand how maternal opioids directly impact the neonatal respiratory system. Breathing is controlled centrally by respiratory networks in the brainstem and spinal cord, but the impact of maternal opioids on developing perinatal respiratory networks has not been studied. Using progressively more isolated respiratory network circuitry, we tested the hypothesis that maternal opioids directly impair neonatal central respiratory control networks. Fictive respiratory-related motor activity from isolated central respiratory networks was age-dependently impaired in neonates after maternal opioids within more complete respiratory networks (brainstem and spinal cords), but unaffected in more isolated networks (medullary slices containing the preBötzinger Complex). These deficits were due, in part, to lingering opioids within neonatal respiratory control networks immediately after birth and involved lasting impairments to respiratory pattern. Since opioids are routinely given to infants with NAS to curb withdrawal symptoms and our previous work demonstrated acute blunting of opioid-induced respiratory depression in neonatal breathing, we further tested the responses of isolated networks to exogenous opioids. Isolated respiratory control networks also demonstrated age-dependent blunted responses to exogenous opioids that correlated with changes in opioid receptor expression within a primary respiratory rhythm generating region, the preBötzinger Complex. Thus, maternal opioids age-dependently impair neonatal central respiratory control and responses to exogenous opioids, suggesting central respiratory impairments contribute to neonatal breathing destabilization after maternal opioids and likely contribute to respiratory distress in infants with NAS. These studies represent a significant advancement of our understanding of the complex effects of maternal opioids, even late in gestation, contributing to neonatal breathing deficits, necessary first steps in developing novel therapeutics to support breathing in infants with NAS.
Collapse
Affiliation(s)
- Sarah A. Beyeler
- Department of Biology, Institute of Neuroscience, University of Oregon, Eugene, OR, United States
| | - Robyn Naidoo
- Department of Human Physiology, University of Oregon, Eugene, OR, United States
| | - Nina R. Morrison
- Department of Human Physiology, University of Oregon, Eugene, OR, United States
| | - Emilee A. McDonald
- Department of Biology, Institute of Neuroscience, University of Oregon, Eugene, OR, United States
| | - David Albarrán
- Department of Human Physiology, University of Oregon, Eugene, OR, United States
| | - Adrianne G. Huxtable
- Department of Biology, Institute of Neuroscience, University of Oregon, Eugene, OR, United States
- Department of Human Physiology, University of Oregon, Eugene, OR, United States
- *Correspondence: Adrianne G. Huxtable,
| |
Collapse
|
4
|
Rosa DS, Frias AT, Vilela-Costa HH, Junior AS, Sant’Ana AB, Fusse EJ, Suchecki D, Campos AC, Lovick TA, Zangrossi H. Neonatal maternal deprivation facilitates the expression of a panic-like escape behavior in adult rats. Behav Brain Res 2022; 434:114031. [DOI: 10.1016/j.bbr.2022.114031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/21/2022] [Accepted: 07/27/2022] [Indexed: 11/02/2022]
|
5
|
Janes TA, Ambrozio-Marques D, Fournier S, Joseph V, Soliz J, Kinkead R. Testosterone Supplementation Induces Age-Dependent Augmentation of the Hypoxic Ventilatory Response in Male Rats With Contributions From the Carotid Bodies. Front Physiol 2022; 12:781662. [PMID: 35002764 PMCID: PMC8741195 DOI: 10.3389/fphys.2021.781662] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 12/03/2021] [Indexed: 12/30/2022] Open
Abstract
Excessive carotid body responsiveness to O2 and/or CO2/H+ stimuli contributes to respiratory instability and apneas during sleep. In hypogonadal men, testosterone supplementation may increase the risk of sleep-disordered breathing; however, the site of action is unknown. The present study tested the hypothesis that testosterone supplementation potentiates carotid body responsiveness to hypoxia in adult male rats. Because testosterone levels decline with age, we also determined whether these effects were age-dependent. In situ hybridization determined that androgen receptor mRNA was present in the carotid bodies and caudal nucleus of the solitary tract of adult (69 days old) and aging (193–206 days old) male rats. In urethane-anesthetized rats injected with testosterone propionate (2 mg/kg; i.p.), peak breathing frequency measured during hypoxia (FiO2 = 0.12) was 11% greater vs. the vehicle treatment group. Interestingly, response intensity following testosterone treatment was positively correlated with animal age. Exposing ex vivo carotid body preparations from young and aging rats to testosterone (5 nM, free testosterone) 90–120 min prior to testing showed that the carotid sinus nerve firing rate during hypoxia (5% CO2 + 95% N2; 15 min) was augmented in both age groups as compared to vehicle (<0.001% DMSO). Ventilatory measurements performed using whole body plethysmography revealed that testosterone supplementation (2 mg/kg; i.p.) 2 h prior reduced apnea frequency during sleep. We conclude that in healthy rats, age-dependent potentiation of the carotid body’s response to hypoxia by acute testosterone supplementation does not favor the occurrence of apneas but rather appears to stabilize breathing during sleep.
Collapse
Affiliation(s)
- Tara A Janes
- Department of Physiology, Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada.,Department of Pediatrics, Québec Heart and Lung Institute, Université Laval, Québec, QC, Canada
| | | | - Sébastien Fournier
- Department of Surgery, Faculty of Medicine, Université Laval, Québec, QC, Canada
| | - Vincent Joseph
- Department of Pediatrics, Québec Heart and Lung Institute, Université Laval, Québec, QC, Canada
| | - Jorge Soliz
- Department of Pediatrics, Québec Heart and Lung Institute, Université Laval, Québec, QC, Canada
| | - Richard Kinkead
- Department of Pediatrics, Québec Heart and Lung Institute, Université Laval, Québec, QC, Canada
| |
Collapse
|
6
|
Elliot-Portal E, Arias-Reyes C, Laouafa S, Tam R, Kinkead R, Soliz J. Cerebral Erythropoietin Prevents Sex-Dependent Disruption of Respiratory Control Induced by Early Life Stress. Front Physiol 2021; 12:701344. [PMID: 34987412 PMCID: PMC8720854 DOI: 10.3389/fphys.2021.701344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 11/22/2021] [Indexed: 11/29/2022] Open
Abstract
Injuries that occur early in life are often at the root of adult illness. Neonatal maternal separation (NMS) is a form of early life stress that has persistent and sex-specific effects on the development of neural networks, including those that regulate breathing. The release of stress hormones during a critical period of development contributes to the deleterious consequences of NMS, but the role of increased corticosterone (CORT) in NMS-induced respiratory disturbance is unknown. Because erythropoietin (EPO) is a potent neuroprotectant that prevents conditions associated with hyperactivation of the stress neuroaxis in a sex-specific manner, we hypothesized that EPO reduces the sex-specific alteration of respiratory regulation induced by NMS in adult mice. Animals were either raised under standard conditions (controls) or exposed to NMS 3 h/day from postnatal days 3–12. We tested the efficacy of EPO in preventing the effects of NMS by comparing wild-type mice with transgenic mice that overexpress EPO only in the brain (Tg21). In 7-days-old pups, NMS augmented CORT levels ~2.5-fold by comparison with controls but only in males; this response was reduced in Tg21 mice. Respiratory function was assessed using whole-body plethysmography. Apneas were detected during sleep; the responsiveness to stimuli was measured by exposing mice to hypoxia (10% O2; 15 min) and hypercapnia (5% CO2; 10 min). In wild-type, NMS increased the number of apneas and the hypercapnic ventilatory response (HcVR) only in males; with no effect on Tg21. In wild-type males, the incidence of apneas was positively correlated with HcVR and inversely related to the tachypneic response to hypoxia. We conclude that neural EPO reduces early life stress-induced respiratory disturbances observed in males.
Collapse
Affiliation(s)
- Elizabeth Elliot-Portal
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec City, QC, Canada
| | - Christian Arias-Reyes
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec City, QC, Canada
| | - Sofien Laouafa
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec City, QC, Canada
| | - Rose Tam
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec City, QC, Canada
| | - Richard Kinkead
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec City, QC, Canada
| | - Jorge Soliz
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec City, QC, Canada
- High Altitude Pulmonary and Pathology Institute (HAPPI–IPPA), La Paz, Bolivia
- *Correspondence: Jorge Soliz,
| |
Collapse
|
7
|
Arias-Reyes C, Laouafa S, Zubieta-DeUrioste N, Joseph V, Bairam A, Schneider Gasser EM, Soliz J. Erythropoietin Produces a Dual Effect on Carotid Body Chemoreception in Male Rats. Front Pharmacol 2021; 12:727326. [PMID: 34594222 PMCID: PMC8476757 DOI: 10.3389/fphar.2021.727326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 08/25/2021] [Indexed: 11/13/2022] Open
Abstract
Erythropoietin (EPO) regulates respiration under conditions of normoxia and hypoxia through interaction with the respiratory centers of the brainstem. Here we investigate the dose-dependent impact of EPO in the CB response to hypoxia and hypercapnia. We show, in isolated "en bloc" carotid body (CB) preparations containing the carotid sinus nerve (CSN) from adult male Sprague Dawley rats, that EPO acts as a stimulator of CSN activity in response to hypoxia at concentrations below 0.5 IU/ml. Under hypercapnic conditions, EPO did not influence the CSN response. EPO concentrations above 0.5 IU/ml decreased the response of the CSN to both hypoxia and hypercapnia, reaching complete inhibition at 2 IU/ml. The inhibitory action of high-dose EPO on the CSN activity might result from an increase in nitric oxide (NO) production. Accordingly, CB preparations were incubated with 2 IU/ml EPO and the unspecific NO synthase inhibitor (L-NAME), or the neuronal-specific NO synthase inhibitor (7NI). Both NO inhibitors fully restored the CSN activity in response to hypoxia and hypercapnia in presence of EPO. Our results show that EPO activates the CB response to hypoxia when its concentration does not exceed the threshold at which NO inhibitors masks EPO's action.
Collapse
Affiliation(s)
- Christian Arias-Reyes
- Université Laval, Faculté de Médecine, Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Département de Pédiatrie, Québec, QC, Canada
| | - Sofien Laouafa
- Université Laval, Faculté de Médecine, Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Département de Pédiatrie, Québec, QC, Canada
| | | | - Vincent Joseph
- Université Laval, Faculté de Médecine, Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Département de Pédiatrie, Québec, QC, Canada
| | - Aida Bairam
- Université Laval, Faculté de Médecine, Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Département de Pédiatrie, Québec, QC, Canada
| | - Edith M Schneider Gasser
- Institute of Veterinary Physiology, Vetsuisse-Faculty, University of Zurich, Zurich, Switzerland.,Center for Neuroscience Zurich (ZNZ), Zurich, Switzerland
| | - Jorge Soliz
- Université Laval, Faculté de Médecine, Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Département de Pédiatrie, Québec, QC, Canada.,High Altitude Pulmonary and Pathology Institute (HAPPI-IPPA), La Paz, Bolivia
| |
Collapse
|
8
|
Kinkead R, Gagnon M, Joseph V, Sériès F, Ambrozio-Marques D. Stress and Loss of Ovarian Function: Novel Insights into the Origins of Sex-Based Differences in the Manifestations of Respiratory Control Disorders During Sleep. Clin Chest Med 2021; 42:391-405. [PMID: 34353446 DOI: 10.1016/j.ccm.2021.04.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The respiratory system of women and men develops and functions in distinct neuroendocrine milieus. Despite differences in anatomy and neural control, homeostasis of arterial blood gases is ensured in healthy individuals regardless of sex. This convergence in function differs from the sex-based differences observed in many respiratory diseases. Sleep-disordered breathing (SDB) results mainly from episodes of upper airway closure. This complex and multifactorial respiratory disorder shows significant sexual dimorphism in its clinical manifestations and comorbidities. Guided by recent progress from basic research, this review discusses the hypothesis that stress is necessary to reveal the sexual dimorphism of SDB.
Collapse
Affiliation(s)
- Richard Kinkead
- Department of Pediatrics, Université Laval, Centre de Recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec, 2725 Chemin Ste-Foy, Québec, Québec G1V 4G5, Canada.
| | - Marianne Gagnon
- Department of Pediatrics, Université Laval, Centre de Recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec, 2725 Chemin Ste-Foy, Québec, Québec G1V 4G5, Canada
| | - Vincent Joseph
- Department of Pediatrics, Université Laval, Centre de Recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec, 2725 Chemin Ste-Foy, Québec, Québec G1V 4G5, Canada
| | - Frédéric Sériès
- Department of Medicine, Université Laval, Centre de Recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec, Québec, Québec, Canada
| | - Danuzia Ambrozio-Marques
- Department of Pediatrics, Université Laval, Centre de Recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec, 2725 Chemin Ste-Foy, Québec, Québec G1V 4G5, Canada
| |
Collapse
|
9
|
Tenorio-Lopes L, Kinkead R. Sex-Specific Effects of Stress on Respiratory Control: Plasticity, Adaptation, and Dysfunction. Compr Physiol 2021; 11:2097-2134. [PMID: 34107062 DOI: 10.1002/cphy.c200022] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
As our understanding of respiratory control evolves, we appreciate how the basic neurobiological principles of plasticity discovered in other systems shape the development and function of the respiratory control system. While breathing is a robust homeostatic function, there is growing evidence that stress disrupts respiratory control in ways that predispose to disease. Neonatal stress (in the form of maternal separation) affects "classical" respiratory control structures such as the peripheral O2 sensors (carotid bodies) and the medulla (e.g., nucleus of the solitary tract). Furthermore, early life stress disrupts the paraventricular nucleus of the hypothalamus (PVH), a structure that has emerged as a primary determinant of the intensity of the ventilatory response to hypoxia. Although underestimated, the PVH's influence on respiratory function is a logical extension of the hypothalamic control of metabolic demand and supply. In this article, we review the functional and anatomical links between the stress neuroendocrine axis and the medullary network regulating breathing. We then present the persistent and sex-specific effects of neonatal stress on respiratory control in adult rats. The similarities between the respiratory phenotype of stressed rats and clinical manifestations of respiratory control disorders such as sleep-disordered breathing and panic attacks are remarkable. These observations are in line with the scientific consensus that the origins of adult disease are often found among developmental and biological disruptions occurring during early life. These observations bring a different perspective on the structural hierarchy of respiratory homeostasis and point to new directions in our understanding of the etiology of respiratory control disorders. © 2021 American Physiological Society. Compr Physiol 11:1-38, 2021.
Collapse
Affiliation(s)
- Luana Tenorio-Lopes
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, Calgary, Alberta, Canada
| | - Richard Kinkead
- Département de Pédiatrie, Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec City, Quebec, Canada
| |
Collapse
|
10
|
Abstract
Carbon dioxide is a common gas in the air which has been widely used in medical treatment. A carbon dioxide molecule consists of two oxygen atoms and one carbon atom through a covalent bond. In the body, carbon dioxide reacts with water to produce carbonic acid. In healthy people, carbon dioxide is maintained within a narrow range (35–45 mmHg) by physiological mechanisms. The role of hypocapnia (partial pressure of carbon dioxide < 35 mmHg) and hypercapnia (partial pressure of carbon dioxide > 45 mmHg) in the nervous system is intricate. Past researches mainly focus on the effect of hypocapnia to nerve protection. Nevertheless, Hypercapnia seems to play an important role in neuroprotection. The mechanisms of hypocapnia and hypercapnia in the nervous system deserve our attention. The purpose of this review is to summarize the effect of hypocapnia and hypercapnia in stroke and traumatic brain injury.
Collapse
Affiliation(s)
- Ru-Ming Deng
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Yong-Chun Liu
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Jin-Quan Li
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Jian-Guo Xu
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Gang Chen
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| |
Collapse
|
11
|
Marques EB, Souza KPD, Alvim-Silva T, Martins ILF, Pedro S, Scaramello CBV. Nutrition and Cardiovascular Diseases: Programming and Reprogramming. INTERNATIONAL JOURNAL OF CARDIOVASCULAR SCIENCES 2021. [DOI: 10.36660/ijcs.20200031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
|
12
|
Tenorio-Lopes L, Fournier S, Henry MS, Bretzner F, Kinkead R. Disruption of estradiol regulation of orexin neurons: a novel mechanism in excessive ventilatory response to CO 2 inhalation in a female rat model of panic disorder. Transl Psychiatry 2020; 10:394. [PMID: 33173029 PMCID: PMC7656265 DOI: 10.1038/s41398-020-01076-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/01/2020] [Accepted: 10/20/2020] [Indexed: 12/27/2022] Open
Abstract
Panic disorder (PD) is ~2 times more frequent in women. An excessive ventilatory response to CO2 inhalation is more likely during the premenstrual phase. While ovarian hormones appear important in the pathophysiology of PD, their role remains poorly understood as female animals are rarely used in pre-clinical studies. Using neonatal maternal separation (NMS) to induce a "PD-like" respiratory phenotype, we tested the hypothesis that NMS disrupts hormonal regulation of the ventilatory response to CO2 in female rats. We then determined whether NMS attenuates the inhibitory actions of 17-β estradiol (E2) on orexin neurons (ORX). Pups were exposed to NMS (3 h/day; postnatal day 3-12). The ventilatory response to CO2-inhalation was tested before puberty, across the estrus cycle, and following ovariectomy. Plasma E2 and hypothalamic ORXA were measured. The effect of an ORX1 antagonist (SB334867; 15 mg/kg) on the CO2 response was tested. Excitatory postsynaptic currents (EPSCs) were recorded from ORX neurons using whole-cell patch-clamp. NMS-related increase in the CO2 response was observed only when ovaries were functional; the largest ventilation was observed during proestrus. SB334867 blocked this effect. NMS augmented levels of ORXA in hypothalamus extracts. EPSC frequency varied according to basal plasma E2 levels across the estrus cycle in controls but not NMS. NMS reproduces developmental and cyclic changes of respiratory manifestations of PD. NMS disrupts the inhibitory actions of E2 on the respiratory network. Impaired E2-related inhibition of ORX neurons during proestrus is a novel mechanism in respiratory manifestations of PD in females.
Collapse
Affiliation(s)
- Luana Tenorio-Lopes
- Hotchkiss Brain Institute; Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Stéphanie Fournier
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec. Département de Pédiatrie. Université Laval, Québec, QC, Canada
| | - Mathilde S Henry
- INRAE, Université de Bordeaux, Bordeaux INP, Nutrineuro, UMR 1286, F-33000, Bordeaux, France
| | - Frédéric Bretzner
- Centre de Recherche du CHU de Québec-Université Laval, Axe Neurosciences. Département de Psychiatrie et de Neurosciences, Université Laval, Québec, QC, Canada
| | - Richard Kinkead
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec. Département de Pédiatrie. Université Laval, Québec, QC, Canada.
| |
Collapse
|
13
|
O'Connor KM, Lucking EF, Cryan JF, O'Halloran KD. Bugs, breathing and blood pressure: microbiota-gut-brain axis signalling in cardiorespiratory control in health and disease. J Physiol 2020; 598:4159-4179. [PMID: 32652603 DOI: 10.1113/jp280279] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 07/07/2020] [Indexed: 12/12/2022] Open
Abstract
There is clear evidence of physiological effects of the gut microbiota on whole-body function in health and disease. Microbiota-gut-brain axis signalling is recognised as a key player in behavioural disorders such as depression and anxiety. Recent evidence suggests that the gut microbiota affects neurocontrol networks responsible for homeostatic functions that are essential for life. We consider the evidence suggesting the potential for the gut microbiota to shape cardiorespiratory homeostasis. In various animal models of disease, there is an association between cardiorespiratory morbidity and perturbed gut microbiota, with strong evidence in support of a role of the gut microbiota in the control of blood pressure. Interventions that target the gut microbiota or manipulate the gut-brain axis, such as short-chain fatty acid supplementation, prevent hypertension in models of obstructive sleep apnoea. Emerging evidence points to a role for the microbiota-gut-brain axis in the control of breathing and ventilatory responsiveness, relevant to cardiorespiratory disease. There is also evidence for an association between the gut microbiota and disease severity in people with asthma and cystic fibrosis. There are many gaps in the knowledge base and an urgent need to better understand the mechanisms by which gut health and dysbiosis contribute to cardiorespiratory control. Nevertheless, there is a growing consensus that manipulation of the gut microbiota could prove an efficacious adjunctive strategy in the treatment of common cardiorespiratory diseases, which are the leading causes of morbidity and mortality.
Collapse
Affiliation(s)
- Karen M O'Connor
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland.,Department of Anatomy & Neuroscience, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland.,APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Eric F Lucking
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - John F Cryan
- Department of Anatomy & Neuroscience, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland.,APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Ken D O'Halloran
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland.,APC Microbiome Ireland, University College Cork, Cork, Ireland
| |
Collapse
|
14
|
Ewald AC, Kiernan EA, Roopra AS, Radcliff AB, Timko RR, Baker TL, Watters JJ. Sex- and Region-Specific Differences in the Transcriptomes of Rat Microglia from the Brainstem and Cervical Spinal Cord. J Pharmacol Exp Ther 2020; 375:210-222. [PMID: 32661056 DOI: 10.1124/jpet.120.266171] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 07/07/2020] [Indexed: 12/11/2022] Open
Abstract
The neural control system underlying breathing is sexually dimorphic with males being more vulnerable to dysfunction. Microglia also display sex differences, and their role in the architecture of brainstem respiratory rhythm circuitry and modulation of cervical spinal cord respiratory plasticity is becoming better appreciated. To further understand the molecular underpinnings of these sex differences, we performed RNA sequencing of immunomagnetically isolated microglia from brainstem and cervical spinal cord of adult male and female rats. We used various bioinformatics tools (Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, Reactome, STRING, MAGICTRICKS) to functionally categorize identified gene sets, as well as to pinpoint common transcriptional gene drivers that may be responsible for the observed transcriptomic differences. We found few sex differences in the microglial transcriptomes derived from the brainstem, but several hundred genes were differentially expressed by sex in cervical spinal microglia. Comparing brainstem and spinal microglia within and between sexes, we found that the major factor guiding transcriptomic differences was central nervous system (CNS) location rather than sex. We further identified key transcriptional drivers that may be responsible for the transcriptomic differences observed between sexes and CNS regions; enhancer of zeste homolog 2 emerged as the predominant driver of the differentially downregulated genes. We suggest that functional gene alterations identified in metabolism, transcription, and intercellular communication underlie critical microglial heterogeneity and sex differences in CNS regions that contribute to respiratory disorders categorized by dysfunction in neural control. These data will also serve as an important resource data base to advance our understanding of innate immune cell contributions to sex differences and the field of respiratory neural control. SIGNIFICANCE STATEMENT: The contributions of central nervous system (CNS) innate immune cells to sexually dimorphic differences in the neural circuitry controlling breathing are poorly understood. We identify key transcriptomic differences, and their transcriptional drivers, in microglia derived from the brainstem and the C3-C6 cervical spinal cord of healthy adult male and female rats. Gene alterations identified in metabolism, gene transcription, and intercellular communication likely underlie critical microglial heterogeneity and sex differences in these key CNS regions that contribute to the neural control of breathing.
Collapse
Affiliation(s)
- Andrea C Ewald
- Departments of Comparative Biosciences (A.C.E., E.A.K., A.B.R., R.R.T., T.L.B., J.J.W.) and Neuroscience (A.S.R.), University of Wisconsin-Madison, Madison, Wisconsin
| | - Elizabeth A Kiernan
- Departments of Comparative Biosciences (A.C.E., E.A.K., A.B.R., R.R.T., T.L.B., J.J.W.) and Neuroscience (A.S.R.), University of Wisconsin-Madison, Madison, Wisconsin
| | - Avtar S Roopra
- Departments of Comparative Biosciences (A.C.E., E.A.K., A.B.R., R.R.T., T.L.B., J.J.W.) and Neuroscience (A.S.R.), University of Wisconsin-Madison, Madison, Wisconsin
| | - Abigail B Radcliff
- Departments of Comparative Biosciences (A.C.E., E.A.K., A.B.R., R.R.T., T.L.B., J.J.W.) and Neuroscience (A.S.R.), University of Wisconsin-Madison, Madison, Wisconsin
| | - Rebecca R Timko
- Departments of Comparative Biosciences (A.C.E., E.A.K., A.B.R., R.R.T., T.L.B., J.J.W.) and Neuroscience (A.S.R.), University of Wisconsin-Madison, Madison, Wisconsin
| | - Tracy L Baker
- Departments of Comparative Biosciences (A.C.E., E.A.K., A.B.R., R.R.T., T.L.B., J.J.W.) and Neuroscience (A.S.R.), University of Wisconsin-Madison, Madison, Wisconsin
| | - Jyoti J Watters
- Departments of Comparative Biosciences (A.C.E., E.A.K., A.B.R., R.R.T., T.L.B., J.J.W.) and Neuroscience (A.S.R.), University of Wisconsin-Madison, Madison, Wisconsin
| |
Collapse
|
15
|
Beyeler SA, Hodges MR, Huxtable AG. Impact of inflammation on developing respiratory control networks: rhythm generation, chemoreception and plasticity. Respir Physiol Neurobiol 2020; 274:103357. [PMID: 31899353 DOI: 10.1016/j.resp.2019.103357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/17/2019] [Accepted: 12/02/2019] [Indexed: 10/25/2022]
Abstract
The respiratory control network in the central nervous system undergoes critical developmental events early in life to ensure adequate breathing at birth. There are at least three "critical windows" in development of respiratory control networks: 1) in utero, 2) newborn (postnatal day 0-4 in rodents), and 3) neonatal (P10-13 in rodents, 2-4 months in humans). During these critical windows, developmental processes required for normal maturation of the respiratory control network occur, thereby increasing vulnerability of the network to insults, such as inflammation. Early life inflammation (induced by LPS, chronic intermittent hypoxia, sustained hypoxia, or neonatal maternal separation) acutely impairs respiratory rhythm generation, chemoreception and increases neonatal risk of mortality. These early life impairments are also greater in young males, suggesting sex-specific impairments in respiratory control. Further, neonatal inflammation has a lasting impact on respiratory control by impairing adult respiratory plasticity. This review focuses on how inflammation alters respiratory rhythm generation, chemoreception and plasticity during each of the three critical windows. We also highlight the need for additional mechanistic studies and increased investigation into how glia (such as microglia and astrocytes) play a role in impaired respiratory control after inflammation. Understanding how inflammation during critical windows of development disrupt respiratory control networks is essential for developing better treatments for vulnerable neonates and preventing adult ventilatory control disorders.
Collapse
Affiliation(s)
- Sarah A Beyeler
- Department of Human Physiology, University of Oregon, Eugene, OR, 97403, United States
| | - Matthew R Hodges
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, United States
| | - Adrianne G Huxtable
- Department of Human Physiology, University of Oregon, Eugene, OR, 97403, United States.
| |
Collapse
|
16
|
Ramirez SC, Koschnitzky JE, Youngquist TM, Baertsch NA, Smith CV, Ramirez JM. Perinatal Breathing Patterns and Survival in Mice Born Prematurely and at Term. Front Physiol 2019; 10:1113. [PMID: 31543825 PMCID: PMC6728753 DOI: 10.3389/fphys.2019.01113] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 08/12/2019] [Indexed: 11/29/2022] Open
Abstract
Infants born prematurely, often associated with maternal infection, frequently exhibit breathing instabilities that require resuscitation. We hypothesized that breathing patterns during the first hour of life would be predictive of survival in an animal model of prematurity. Using plethysmography, we measured breathing patterns during the first hour after birth in mice born at term (Term 19.5), delivered prematurely on gestational day 18.5 following administration of low-dose lipopolysaccharide (LPS; 0.14 mg/kg) to pregnant dams (LPS 18.5), or delivered on gestational day 18.7 or 17.5 by caesarian section (C-S 18.5 and C-S 17.5, respectively). Our experimental approach allowed us to dissociate effects caused by inflammation, from effects due to premature birth in the absence of an inflammatory response. C-S 17.5 mice did not survive, whereas mortality was not increased in C-S 18.5 mice. However, in premature pups born at the same gestational age (day 18.5) in response to maternal LPS injection, mortality was significantly increased. Overall, mice that survived had higher birth weights and showed eupneic or gasping activity that was able to transition to normal breathing. Some mice also exhibited a “saw tooth” breathing pattern that was able to transition into eupnea during the first hour of life. In contrast, mice that did not survive showed distinct, large amplitude, long-lasting breaths that occurred at low frequency and did not transition into eupnea. This breathing pattern was only observed during the first hour of life and was more prevalent in LPS 18.5 and C-S 18.5 mice. Indeed, breath tidal volumes were higher in inflammation-induced premature pups than in pups delivered via C-section at equivalent gestational ages, whereas breathing frequencies were low in both LPS-induced and C-section-induced premature pups. We conclude that a breathing pattern characterized by low frequency and large tidal volume is a predictor for the failure to survive, and that these characteristics are more often seen when prematurity occurs in the context of maternal inflammation. Further insights into the mechanisms that generate these breathing patterns and how they transition to normal breathing may facilitate development of novel strategies to manage premature birth in humans.
Collapse
Affiliation(s)
- Sanja C Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States
| | - Jenna E Koschnitzky
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States
| | - Tiffany M Youngquist
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States
| | - Nathan A Baertsch
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States
| | - Charles V Smith
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Neurological Surgery, University of Washington School of Medicine, Seattle, WA, United States
| |
Collapse
|
17
|
O'Connor KM, Lucking EF, Golubeva AV, Strain CR, Fouhy F, Cenit MC, Dhaliwal P, Bastiaanssen TFS, Burns DP, Stanton C, Clarke G, Cryan JF, O'Halloran KD. Manipulation of gut microbiota blunts the ventilatory response to hypercapnia in adult rats. EBioMedicine 2019; 44:618-638. [PMID: 30898652 PMCID: PMC6606895 DOI: 10.1016/j.ebiom.2019.03.029] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 03/08/2019] [Accepted: 03/11/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND It is increasingly evident that perturbations to the diversity and composition of the gut microbiota have significant consequences for the regulation of integrative physiological systems. There is growing interest in the potential contribution of microbiota-gut-brain signalling to cardiorespiratory control in health and disease. METHODS In adult male rats, we sought to determine the cardiorespiratory effects of manipulation of the gut microbiota following a 4-week administration of a cocktail of antibiotics. We subsequently explored the effects of administration of faecal microbiota from pooled control (vehicle) rat faeces, given by gavage to vehicle- and antibiotic-treated rats. FINDINGS Antibiotic intervention depressed the ventilatory response to hypercapnic stress in conscious animals, owing to a reduction in the respiratory frequency response to carbon dioxide. Baseline frequency, respiratory timing variability, and the expression of apnoeas and sighs were normal. Microbiota-depleted rats had decreased systolic blood pressure. Faecal microbiota transfer to vehicle- and antibiotic-treated animals also disrupted the gut microbiota composition, associated with depressed ventilatory responsiveness to hypercapnia. Chronic antibiotic intervention or faecal microbiota transfer both caused significant disruptions to brainstem monoamine neurochemistry, with increased homovanillic acid:dopamine ratio indicative of increased dopamine turnover, which correlated with the abundance of several bacteria of six different phyla. INTERPRETATION Chronic antibiotic administration and faecal microbiota transfer disrupt gut microbiota, brainstem monoamine concentrations and the ventilatory response to hypercapnia. We suggest that aberrant microbiota-gut-brain axis signalling has a modulatory influence on respiratory behaviour during hypercapnic stress. FUND: Department of Physiology and APC Microbiome Ireland, University College Cork, Ireland.
Collapse
Affiliation(s)
- Karen M O'Connor
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland; Department of Anatomy & Neuroscience, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland; APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Eric F Lucking
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - Anna V Golubeva
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Conall R Strain
- Teagasc Food Research Centre, Moorepark, Fermoy, County Cork, Ireland
| | - Fiona Fouhy
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Teagasc Food Research Centre, Moorepark, Fermoy, County Cork, Ireland
| | - María C Cenit
- Department of Anatomy & Neuroscience, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland; Institute of Agrochemistry and Food Technology (IATA), National Council for Scientific Research (CSIC), Valencia, Spain
| | - Pardeep Dhaliwal
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - Thomaz F S Bastiaanssen
- Department of Anatomy & Neuroscience, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland; APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - David P Burns
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - Catherine Stanton
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Teagasc Food Research Centre, Moorepark, Fermoy, County Cork, Ireland
| | - Gerard Clarke
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - John F Cryan
- Department of Anatomy & Neuroscience, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland; APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Ken D O'Halloran
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland; APC Microbiome Ireland, University College Cork, Cork, Ireland.
| |
Collapse
|
18
|
Battaglia M, Khan WU. Reappraising Preclinical Models of Separation Anxiety Disorder, Panic Disorder, and CO 2 Sensitivity: Implications for Methodology and Translation into New Treatments. Curr Top Behav Neurosci 2018; 40:195-217. [PMID: 29696603 DOI: 10.1007/7854_2018_42] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Separation anxiety applies to multiple forms of distress responses seen in mammals during postnatal development, including separation from a caregiver. Childhood separation anxiety disorder is an important risk factor for developing panic disorder in early adulthood, and both conditions display an increased sensitivity to elevated CO2 concentrations inhaled from the air. By interfacing epidemiological, genetic, and physiological knowledge with preclinical animal research models, it is possible to decipher the mechanisms that are central to separation anxiety and panic disorders while also suggesting possible therapies. Preclinical research models allow for environmentally controlled studies of early interferences with parental care. These models have shown that different forms of early maternal separation in mice and rats induce elevated CO2 respiratory sensitivity, an important biomarker of separation anxiety and panic disorders. In mice, this is likely due to gene-environment interactions that affect multiple behavioural and physical phenotypes after exposure to this early adversity. Although several questions regarding the causal mechanism of separation anxiety and panic disorder remain unanswered, the identification and improved understanding of biomarkers that link these mental health conditions under the guise of preclinical research models in conjunction with human longitudinal cohort studies can help resolve these issues.
Collapse
Affiliation(s)
- Marco Battaglia
- Division of Child, Youth and Emerging Adulthood Psychiatry, Centre for Addiction & Mental Health, Toronto, ON, Canada.
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
| | - Waqas Ullah Khan
- Division of Child, Youth and Emerging Adulthood Psychiatry, Centre for Addiction & Mental Health, Toronto, ON, Canada
- School of Medicine, Faculty of Health Sciences, Trinity College Dublin, Dublin, Ireland
| |
Collapse
|
19
|
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] [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.
Collapse
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
| |
Collapse
|
20
|
Rousseau JP, Tenorio-Lopes L, Baldy C, Janes TA, Fournier S, Kinkead R. On the origins of sex-based differences in respiratory disorders: Lessons and hypotheses from stress neuroendocrinology in developing rats. Respir Physiol Neurobiol 2017; 245:105-121. [DOI: 10.1016/j.resp.2017.03.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 03/28/2017] [Accepted: 03/31/2017] [Indexed: 12/31/2022]
|