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Dai Y, Duan K, Huang G, Yang X, Jiang X, Chen J, Liu P. Inhalation of electronic cigarettes slightly affects lung function and inflammation in mice. FRONTIERS IN TOXICOLOGY 2023; 5:1232040. [PMID: 37731664 PMCID: PMC10507352 DOI: 10.3389/ftox.2023.1232040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 07/14/2023] [Indexed: 09/22/2023] Open
Abstract
Electronic cigarettes have become increasingly popular, but the results of previous studies on electronic cigarette exposure in animals have been equivocal. This study aimed to evaluate the effects of electronic cigarette smoke (ECS) and cigarette smoke (CS) on lung function and pulmonary inflammation in mice to investigate whether electronic cigarettes are safer when compared to cigarettes. 32 specific pathogen-free BALB/c male mice were randomly grouped and exposed to fresh air (control), mint-flavored ECS (ECS1, 6 mg/kg), cheese-flavored ECS (ECS2, 6 mg/kg), and CS (6 mg/kg). After 3 weeks exposure to ECS or CS, we measured lung function (PIF and Penh) and blood oxygen saturation. The levels of TNF-α and IL-6 in the bronchoalveolar lavage fluid (BALF) and serum were measured using ELISA. HE staining was performed to observe the pathological changes in the lung tissues. The levels of IL-6 in BALF and serum, and TNF-α in BALF, were elevated similarly in the ECS and CS groups compared to the control group. Significant elevation was observed in serum TNF-α levels in the CS group. The total count of cells in BALF were increased after ECS1 exposure and CS exposure. PIF and oxygen saturation decreased, and Penh increased markedly in the CS group but not in the ECS groups. Compared with the ECS groups, mice in the CS group had widened lung tissue septa and increased inflammatory cell infiltration. However, we did not detect significant differences between mint-flavored and cheese-flavored e-cigarettes in our study. Overall, our findings suggested that both ECS and CS impair lung function and histopathology while promoting inflammation. In contrast, ECS has a less negative impact than CS.
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Affiliation(s)
- Yuxing Dai
- Department of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Kun Duan
- RELX Science Center, Shenzhen RELX Tech Co., Ltd., Shenzhen, China
| | - Guangye Huang
- Department of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Xuemin Yang
- RELX Science Center, Shenzhen RELX Tech Co., Ltd., Shenzhen, China
| | - Xingtao Jiang
- RELX Science Center, Shenzhen RELX Tech Co., Ltd., Shenzhen, China
| | - Jianwen Chen
- Department of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, Guangdong, China
- National and Local Joint Engineering Laboratory of Druggability and New Drugs Evaluation, Guangdong Engineering Laboratory of Druggability and New Drug Evaluation, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Peiqing Liu
- Department of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, Guangdong, China
- National and Local Joint Engineering Laboratory of Druggability and New Drugs Evaluation, Guangdong Engineering Laboratory of Druggability and New Drug Evaluation, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
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2
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Krohn F, Novello M, van der Giessen RS, De Zeeuw CI, Pel JJM, Bosman LWJ. The integrated brain network that controls respiration. eLife 2023; 12:83654. [PMID: 36884287 PMCID: PMC9995121 DOI: 10.7554/elife.83654] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 01/29/2023] [Indexed: 03/09/2023] Open
Abstract
Respiration is a brain function on which our lives essentially depend. Control of respiration ensures that the frequency and depth of breathing adapt continuously to metabolic needs. In addition, the respiratory control network of the brain has to organize muscular synergies that integrate ventilation with posture and body movement. Finally, respiration is coupled to cardiovascular function and emotion. Here, we argue that the brain can handle this all by integrating a brainstem central pattern generator circuit in a larger network that also comprises the cerebellum. Although currently not generally recognized as a respiratory control center, the cerebellum is well known for its coordinating and modulating role in motor behavior, as well as for its role in the autonomic nervous system. In this review, we discuss the role of brain regions involved in the control of respiration, and their anatomical and functional interactions. We discuss how sensory feedback can result in adaptation of respiration, and how these mechanisms can be compromised by various neurological and psychological disorders. Finally, we demonstrate how the respiratory pattern generators are part of a larger and integrated network of respiratory brain regions.
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Affiliation(s)
- Friedrich Krohn
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | - Manuele Novello
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | | | - Chris I De Zeeuw
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands.,Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Amsterdam, Netherlands
| | - Johan J M Pel
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
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3
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Moreira TS, Sobrinho CR, Falquetto B, Oliveira LM, Lima JD, Mulkey DK, Takakura AC. The retrotrapezoid nucleus and the neuromodulation of breathing. J Neurophysiol 2020; 125:699-719. [PMID: 33427575 DOI: 10.1152/jn.00497.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Breathing is regulated by a host of arousal and sleep-wake state-dependent neuromodulators to maintain respiratory homeostasis. Modulators such as acetylcholine, norepinephrine, histamine, serotonin (5-HT), adenosine triphosphate (ATP), substance P, somatostatin, bombesin, orexin, and leptin can serve complementary or off-setting functions depending on the target cell type and signaling mechanisms engaged. Abnormalities in any of these modulatory mechanisms can destabilize breathing, suggesting that modulatory mechanisms are not overly redundant but rather work in concert to maintain stable respiratory output. The present review focuses on the modulation of a specific cluster of neurons located in the ventral medullary surface, named retrotrapezoid nucleus, that are activated by changes in tissue CO2/H+ and regulate several aspects of breathing, including inspiration and active expiration.
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Affiliation(s)
- Thiago S Moreira
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Cleyton R Sobrinho
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Barbara Falquetto
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Luiz M Oliveira
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Janayna D Lima
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
| | - Daniel K Mulkey
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Ana C Takakura
- Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo (USP), São Paulo, Brazil
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4
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A Leptin-Mediated Neural Mechanism Linking Breathing to Metabolism. Cell Rep 2020; 33:108358. [PMID: 33176139 DOI: 10.1016/j.celrep.2020.108358] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/27/2020] [Accepted: 10/16/2020] [Indexed: 01/10/2023] Open
Abstract
Breathing is coupled to metabolism. Leptin, a peptide mainly secreted in proportion to adipose tissue mass, increases energy expenditure with a parallel increase in breathing. We demonstrate that optogenetic activation of LepRb neurons in the nucleus of the solitary tract (NTS) mimics the respiratory stimulation after systemic leptin administration. We show that leptin activates the sodium leak channel (NALCN), thereby depolarizing a subset of glutamatergic (VGluT2) LepRb NTS neurons expressing galanin. Mice with selective deletion of NALCN in LepRb neurons have increased breathing irregularity and central apneas. On a high-fat diet, these mice gain weight with an associated depression of minute ventilation and tidal volume, which are not detected in control littermates. Anatomical mapping reveals LepRb NTS-originating glutamatergic axon terminals in a brainstem inspiratory premotor region (rVRG) and dorsomedial hypothalamus. These findings directly link a defined subset of NTS LepRb cells to the matching of ventilation to energy balance.
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5
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Gauda EB, Conde S, Bassi M, Zoccal DB, Almeida Colombari DS, Colombari E, Despotovic N. Leptin: Master Regulator of Biological Functions that Affects Breathing. Compr Physiol 2020; 10:1047-1083. [PMID: 32941688 DOI: 10.1002/cphy.c190031] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Obesity is a global epidemic in developed countries accounting for many of the metabolic and cardiorespiratory morbidities that occur in adults. These morbidities include type 2 diabetes, sleep-disordered breathing (SDB), obstructive sleep apnea, chronic intermittent hypoxia, and hypertension. Leptin, produced by adipocytes, is a master regulator of metabolism and of many other biological functions including central and peripheral circuits that control breathing. By binding to receptors on cells and neurons in the brainstem, hypothalamus, and carotid body, leptin links energy and metabolism to breathing. In this comprehensive article, we review the central and peripheral locations of leptin's actions that affect cardiorespiratory responses during health and disease, with a particular focus on obesity, SDB, and its effects during early development. Obesity-induced hyperleptinemia is associated with centrally mediated hypoventilation with decrease CO2 sensitivity. On the other hand, hyperleptinemia augments peripheral chemoreflexes to hypoxia and induces sympathoexcitation. Thus, "leptin resistance" in obesity is relative. We delineate the circuits responsible for these divergent effects, including signaling pathways. We review the unique effects of leptin during development on organogenesis, feeding behavior, and cardiorespiratory responses, and how undernutrition and overnutrition during critical periods of development can lead to cardiorespiratory comorbidities in adulthood. We conclude with suggestions for future directions to improve our understanding of leptin dysregulation and associated clinical diseases and possible therapeutic targets. Lastly, we briefly discuss the yin and the yang, specifically the contribution of relative adiponectin deficiency in adults with hyperleptinemia to the development of metabolic and cardiovascular disease. © 2020 American Physiological Society. Compr Physiol 10:1047-1083, 2020.
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Affiliation(s)
- Estelle B Gauda
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Silvia Conde
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Lisboa, Portugal
| | - Mirian Bassi
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Daniel B Zoccal
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Debora Simoes Almeida Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Nikola Despotovic
- Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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6
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Speretta GF, Lemes EV, Vendramini RC, Menani JV, Zoccal DB, Colombari E, Colombari DSA, Bassi M. High-fat diet increases respiratory frequency and abdominal expiratory motor activity during hypercapnia. Respir Physiol Neurobiol 2018; 258:32-39. [PMID: 30308245 PMCID: PMC6317333 DOI: 10.1016/j.resp.2018.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 10/05/2018] [Accepted: 10/06/2018] [Indexed: 11/24/2022]
Abstract
Breathing disorders are commonly observed in association with obesity. Here we tested whether high-fat diet (HFD) impairs the chemoreflex ventilatory response. Male Holtzman rats (300-320 g) were fed with standard chow diet (SD) or HFD for 12 weeks. Then, tidal volume (VT), respiratory frequency (fR) and pulmonary ventilation (VE) were determined in conscious rats during basal condition, hypercapnia (7% or 10% CO2) or hypoxia (7% O2). The mean arterial pressure (MAP), heart rate (HR) and baroreflex sensitivity were also evaluated in conscious rats. A group of anesthetized rats was used for the measurements of the activity of inspiratory (diaphragm) and expiratory (abdominal) muscles under the same gas conditions. Baseline fR, VT and VE were similar between SD and HFD rats. During hypercapnia, the increase of fR was exacerbated in conscious HFD rats (60 ± 3, vs. SD: 47 ± 3 Δ breaths.min-1, P < 0.05). In anesthetized rats, hypercapnia strongly increased abdominal muscle activity in HFD group (238 ± 27, vs. basal condition: 100 ± 0.3%; P < 0.05), without significant change in SD group (129 ± 2.1, vs. basal condition: 100 ± 0.8%; P = 0.34). The ventilatory responses to hypoxia were similar between groups. In conscious HFD rats, MAP and HR were elevated and the baroreflex function was impaired (P < 0.05). These data demonstrated that 12 weeks of HFD exaggerate the ventilatory response activated by hypercapnia. The mechanisms involved in these responses need more investigation in future studies.
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Affiliation(s)
- Guilherme F Speretta
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil.
| | - Eduardo Vieira Lemes
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil
| | - Regina C Vendramini
- Department of Clinical Analysis, School of Pharmaceutical Sciences, UNESP, Araraquara, SP, Brazil
| | - José V Menani
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil
| | - Daniel B Zoccal
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil
| | - Débora S A Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil
| | - Mirian Bassi
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil.
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7
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Yuan F, Wang H, Feng J, Wei Z, Yu H, Zhang X, Zhang Y, Wang S. Leptin Signaling in the Carotid Body Regulates a Hypoxic Ventilatory Response Through Altering TASK Channel Expression. Front Physiol 2018; 9:249. [PMID: 29636698 PMCID: PMC5881163 DOI: 10.3389/fphys.2018.00249] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 03/06/2018] [Indexed: 11/23/2022] Open
Abstract
Leptin is an adipose-derived hormone that plays an important role in the regulation of breathing. It has been demonstrated that obesity-related hypoventilation or apnea is closely associated with leptin signaling pathways. Perturbations of leptin signaling probably contribute to the reduced sensitivity of respiratory chemoreceptors to hypoxia/hypercapnia. However, the underlying mechanism remains incompletely understood. The present study is to test the hypothesis that leptin signaling contributes to modulating a hypoxic ventilatory response. The respiratory function was assessed in conscious obese Zucker rats or lean littermates treated with an injection of leptin. During exposure to hypoxia, the change in minute ventilation was lower in obese Zucker rats than chow-fed lean littermates or high fat diet-fed littermates. Such a change was abolished in all groups after carotid body denervation. In addition, the expression of phosphorylated signal transducers and activators of transcription 3 (pSTAT3), as well as putative O2-sensitive K+ channels including TASK-1, TASK-3 and TASK-2 in the carotid body, was significantly reduced in obese Zucker rats compared with the other two phenotype littermates. Chronic administration of leptin in chow-fed lean Zucker rats failed to alter basal ventilation but vigorously increased tidal volume, respiratory frequency, and therefore minute volume during exposure to hypoxia. Likewise, carotid body denervation abolished such an effect. In addition, systemic leptin elicited enhanced expression of pSTAT3 and TASK channels. In conclusion, these data demonstrate that leptin signaling facilitates hypoxic ventilatory responses probably through upregulation of pSTAT3 and TASK channels in the carotid body. These findings may help to better understand the pathogenic mechanism of obesity-related hypoventilation or apnea.
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Affiliation(s)
- Fang Yuan
- Department of Physiology, Hebei Medical University, Shijiazhuang, China.,Hebei Key Laboratory of Vascular Homeostasis and Hebei Collaborative Innovation Center for Cardio-Cerebrovascular Disease, Shijiazhuang, China
| | - Hanqiao Wang
- Department of Sleep, Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Jiaqi Feng
- Department of Physiology, Hebei Medical University, Shijiazhuang, China
| | - Ziqian Wei
- Department of Physiology, Hebei Medical University, Shijiazhuang, China
| | - Hongxiao Yu
- Department of Physiology, Hebei Medical University, Shijiazhuang, China
| | - Xiangjian Zhang
- Hebei Key Laboratory of Vascular Homeostasis and Hebei Collaborative Innovation Center for Cardio-Cerebrovascular Disease, Shijiazhuang, China.,Department of Neurology, Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Yi Zhang
- Department of Physiology, Hebei Medical University, Shijiazhuang, China.,Hebei Key Laboratory of Vascular Homeostasis and Hebei Collaborative Innovation Center for Cardio-Cerebrovascular Disease, Shijiazhuang, China
| | - Sheng Wang
- Department of Physiology, Hebei Medical University, Shijiazhuang, China.,Hebei Key Laboratory of Vascular Homeostasis and Hebei Collaborative Innovation Center for Cardio-Cerebrovascular Disease, Shijiazhuang, China
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8
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Gauda EB, Master Z. Contribution of relative leptin and adiponectin deficiencies in premature infants to chronic intermittent hypoxia: Exploring a new hypothesis. Respir Physiol Neurobiol 2017; 256:119-127. [PMID: 29246449 DOI: 10.1016/j.resp.2017.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 11/08/2017] [Accepted: 12/06/2017] [Indexed: 12/15/2022]
Abstract
Chronic intermittent hypoxia (CIH) occurs frequently in premature infants who have apnea of prematurity. Immaturity of the respiratory network from low central respiratory drive and the greater contribution of the carotid body on baseline breathing leads to respiratory instability in premature infants presenting as apnea and periodic breathing. During the 2nd week after birth, the smallest and the youngest premature infants have increased frequency of apnea and periodic breathing and associated oxygen desaturations that can persist for weeks after birth. CIH increases the production of reactive oxygen species that causes tissue damage. Premature infants have decreased capacity to scavenge reactive oxygen species. Oxidative injury is the cause of many of the co-morbidities that are seen in premature infants. In this review we discuss who low fat mass and the resulting relative deficiencies in leptin and adiponectin could contribute to the increase frequency of oxygen desaturations that occurs days after birth in the smallest and youngest premature infants. Leptin is a central respiratory stimulant and adiponectin protects the lung from vascular leak, oxidative injury and vascular remodeling.
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Affiliation(s)
- Estelle B Gauda
- The Hospital for Sick Children, Division of Neonatology, 555 University Ave, Toronto, Ontario, M5G 1X8, Canada.
| | - Zankhana Master
- Department of Pediatrics, Division of Neonatology, University of Missouri, Columbia, MO 65211, United States.
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9
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Kaczyńska K, Zając D, Wojciechowski P, Kogut E, Szereda-Przestaszewska M. Neuropeptides and breathing in health and disease. Pulm Pharmacol Ther 2017; 48:217-224. [PMID: 29223509 DOI: 10.1016/j.pupt.2017.12.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 11/20/2017] [Accepted: 12/05/2017] [Indexed: 12/18/2022]
Abstract
Regulatory neuropeptides control and regulate breathing in physiological and pathophysiological conditions. While they have been identified in the neurons of major respiratory areas, they can be active not only at the central level, but also at the periphery via chemoreceptors, vagal afferents, or locally within lungs and airways. Some neuropeptides, such as leptin or substance P, are respiratory stimulants; others, such as neurotensin, produce variable effects on respiration depending on the site of application. Some neuropeptides have been implicated in pathological states, such as obstructive sleep apnea or asthma. This article provides a concise review of the possible role and functions of several selected neuropeptides in the process of breathing in health and disease and in lung pathologies.
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Affiliation(s)
- Katarzyna Kaczyńska
- Laboratory of Respiration Physiology, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland.
| | - Dominika Zając
- Laboratory of Respiration Physiology, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland
| | - Piotr Wojciechowski
- Laboratory of Respiration Physiology, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland
| | - Ewelina Kogut
- Laboratory of Respiration Physiology, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland
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10
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Bassi M, Furuya WI, Zoccal DB, Menani JV, Colombari DSA, Mulkey DK, Colombari E. Facilitation of breathing by leptin effects in the central nervous system. J Physiol 2016; 594:1617-25. [PMID: 26095748 PMCID: PMC4799963 DOI: 10.1113/jp270308] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 05/13/2015] [Indexed: 01/01/2023] Open
Abstract
With the global epidemic of obesity, breathing disorders associated with excess body weight have markedly increased. Respiratory dysfunctions caused by obesity were originally attributed to mechanical factors; however, recent studies have suggested a pathophysiological component that involves the central nervous system (CNS) and hormones such as leptin produced by adipocytes as well as other cells. Leptin is suggested to stimulate breathing and leptin deficiency causes an impairment of the chemoreflex, which can be reverted by leptin therapy. This facilitation of the chemoreflex may depend on the action of leptin in the hindbrain areas involved in the respiratory control such as the nucleus of the solitary tract (NTS), a site that receives chemosensory afferents, and the ventral surface of the medulla that includes the retrotrapezoid nucleus (RTN), a central chemosensitive area, and the rostral ventrolateral medulla (RVLM). Although the mechanisms and pathways activated by leptin to facilitate breathing are still not completely clear, evidence suggests that the facilitatory effects of leptin on breathing require the brain melanocortin system, including the POMC-MC4R pathway, a mechanism also activated by leptin to modulate blood pressure. The results of all the studies that have investigated the effect of leptin on breathing suggest that disruption of leptin signalling as caused by obesity-induced reduction of central leptin function (leptin resistance) is a relevant mechanism that may contribute to respiratory dysfunctions associated with obesity.
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Affiliation(s)
- M. Bassi
- Department of Physiology and Pathology, School of DentistrySão Paulo State University (UNESP)AraraquaraSPBrazil
| | - W. I. Furuya
- Department of Physiology and Pathology, School of DentistrySão Paulo State University (UNESP)AraraquaraSPBrazil
| | - D. B. Zoccal
- Department of Physiology and Pathology, School of DentistrySão Paulo State University (UNESP)AraraquaraSPBrazil
| | - J. V. Menani
- Department of Physiology and Pathology, School of DentistrySão Paulo State University (UNESP)AraraquaraSPBrazil
| | - D. S. A. Colombari
- Department of Physiology and Pathology, School of DentistrySão Paulo State University (UNESP)AraraquaraSPBrazil
| | - D. K. Mulkey
- Department of Physiology and NeurobiologyUniversity of ConnecticutStorrsCTUSA
| | - E. Colombari
- Department of Physiology and Pathology, School of DentistrySão Paulo State University (UNESP)AraraquaraSPBrazil
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11
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Bassi M, Furuya WI, Zoccal DB, Menani JV, Colombari E, Hall JE, da Silva AA, do Carmo JM, Colombari DSA. Control of respiratory and cardiovascular functions by leptin. Life Sci 2015; 125:25-31. [PMID: 25645056 PMCID: PMC4355938 DOI: 10.1016/j.lfs.2015.01.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 12/19/2014] [Accepted: 01/23/2015] [Indexed: 01/29/2023]
Abstract
Leptin, a peptide hormone produced by adipose tissue, acts in brain centers that control critical physiological functions such as metabolism, breathing and cardiovascular regulation. The importance of leptin for respiratory control is evident by the fact that leptin deficient mice exhibit impaired ventilatory responses to carbon dioxide (CO2), which can be corrected by intracerebroventricular leptin replacement therapy. Leptin is also recognized as an important link between obesity and hypertension. Humans and animal models lacking either leptin or functional leptin receptors exhibit many characteristics of the metabolic syndrome, including hyperinsulinemia, insulin resistance, hyperglycemia, dyslipidemia and visceral adiposity, but do not exhibit increased sympathetic nerve activity (SNA) and have normal to lower blood pressure (BP) compared to lean controls. Even though previous studies have extensively focused on the brain sites and intracellular signaling pathways involved in leptin effects on food intake and energy balance, the mechanisms that mediate the actions of leptin on breathing and cardiovascular function are only beginning to be elucidated. This mini-review summarizes recent advances on the effects of leptin on cardiovascular and respiratory control with emphasis on the neural control of respiratory function and autonomic activity.
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Affiliation(s)
- M Bassi
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil.
| | - W I Furuya
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil
| | - D B Zoccal
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil
| | - J V Menani
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil
| | - E Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil
| | - J E Hall
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA
| | - A A da Silva
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA
| | - J M do Carmo
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA
| | - D S A Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil
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12
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The Carotid Body Does Not Mediate the Acute Ventilatory Effects of Leptin. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 860:379-85. [DOI: 10.1007/978-3-319-18440-1_43] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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13
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Pye RL, Dunn EJ, Ricker EM, Jurcsisn JG, Barr BL, Wyatt CN. Acutely Administered Leptin Increases [Ca2+] i and BK Ca Currents But Does Not Alter Chemosensory Behavior in Rat Carotid Body Type I Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 860:61-7. [PMID: 26303468 DOI: 10.1007/978-3-319-18440-1_8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Obesity related pathologies are the health care crisis of our generation. The fat cell derived adipokine leptin has been shown to be a central stimulant of respiration. Very high levels of leptin, however, are associated with the depressed ventilatory phenotype observed in obesity hypoventilation syndrome. Leptin receptors have been identified on carotid body type I cells but how their activation might influence the physiology of these cells is not known.The acute application of leptin evoked calcium signaling responses in isolated type I cells. Cells increased their Fura 2 ratio by 0.074 ± 0.010 ratio units (n = 39, P < 0.001). Leptin also increased the peak membrane currents in 6 of 9 cells increasing the peak macroscopic currents at +10 mV by 61 ± 14 % (p < 0.02). Leptin administered in the presence of the selective BK(Ca) channel inhibitor Paxilline (0.5 μM) failed to increase membrane currents (n = 5). Interestingly, leptin did not significantly alter the resting membrane potential of isolated type I cells (n = 9) and anoxic/acidic depolarizations were unaffected by leptin (n = 7, n = 6).These data suggest that leptin receptors are functional in type I cells but that their acute activation does not alter chemosensory properties. Future studies will use chronic models of leptin dysregulation.
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Affiliation(s)
- Richard L Pye
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, 3640 Colonel Glenn Hwy, Dayton, OH, 45435, USA
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Zoccal DB, Furuya WI, Bassi M, Colombari DSA, Colombari E. The nucleus of the solitary tract and the coordination of respiratory and sympathetic activities. Front Physiol 2014; 5:238. [PMID: 25009507 PMCID: PMC4070480 DOI: 10.3389/fphys.2014.00238] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 06/09/2014] [Indexed: 12/15/2022] Open
Abstract
It is well known that breathing introduces rhythmical oscillations in the heart rate and arterial pressure levels. Sympathetic oscillations coupled to the respiratory activity have been suggested as an important homeostatic mechanism optimizing tissue perfusion and blood gas uptake/delivery. This respiratory-sympathetic coupling is strengthened in conditions of blood gas challenges (hypoxia and hypercapnia) as a result of the synchronized activation of brainstem respiratory and sympathetic neurons, culminating with the emergence of entrained cardiovascular and respiratory reflex responses. Studies have proposed that the ventrolateral region of the medulla oblongata is a major site of synaptic interaction between respiratory and sympathetic neurons. However, other brainstem regions also play a relevant role in the patterning of respiratory and sympathetic motor outputs. Recent findings suggest that the neurons of the nucleus of the solitary tract (NTS), in the dorsal medulla, are essential for the processing and coordination of respiratory and sympathetic responses to hypoxia. The NTS is the first synaptic station of the cardiorespiratory afferent inputs, including peripheral chemoreceptors, baroreceptors and pulmonary stretch receptors. The synaptic profile of the NTS neurons receiving the excitatory drive from afferent inputs is complex and involves distinct neurotransmitters, including glutamate, ATP and acetylcholine. In the present review we discuss the role of the NTS circuitry in coordinating sympathetic and respiratory reflex responses. We also analyze the neuroplasticity of NTS neurons and their contribution for the development of cardiorespiratory dysfunctions, as observed in neurogenic hypertension, obstructive sleep apnea and metabolic disorders.
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Affiliation(s)
- Daniel B Zoccal
- Department of Physiology and Pathology, School of Dentistry of Araraquara, São Paulo State University (UNESP) Araraquara, Brazil
| | - Werner I Furuya
- Department of Physiology and Pathology, School of Dentistry of Araraquara, São Paulo State University (UNESP) Araraquara, Brazil
| | - Mirian Bassi
- Department of Physiology and Pathology, School of Dentistry of Araraquara, São Paulo State University (UNESP) Araraquara, Brazil
| | - Débora S A Colombari
- Department of Physiology and Pathology, School of Dentistry of Araraquara, São Paulo State University (UNESP) Araraquara, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, School of Dentistry of Araraquara, São Paulo State University (UNESP) Araraquara, Brazil
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