1
|
A novel study to classify breath inhalation and breath exhalation using audio signals from heart and trachea. Biomed Signal Process Control 2023. [DOI: 10.1016/j.bspc.2022.104220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
2
|
Marques DA, Gargaglioni LH, Joseph V, Bretzner F, Bícego KC, Fournier S, Kinkead R. Impact of ovariectomy and CO 2 inhalation on microglia morphology in select brainstem and hypothalamic areas regulating breathing in female rats. Brain Res 2021; 1756:147276. [PMID: 33422531 DOI: 10.1016/j.brainres.2021.147276] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/22/2020] [Accepted: 01/02/2021] [Indexed: 11/17/2022]
Abstract
The neural network that regulates breathing shows a significant sexual dimorphism. Ovarian hormones contribute to this distinction as, in rats, ovariectomy reduces the ventilatory response to CO2. Microglia are neuroimmune cells that are sensitive to neuroendocrine changes in their environment. When reacting to challenging conditions, these cells show changes in their morphology that reflect an augmented capacity for producing pro- and anti-inflammatory cytokines. Based on evidence suggesting that microglia contribute to sex-based differences in reflexive responses to hypercapnia, we hypothesized that ovariectomy and hypercapnia promote microglial reactivity in selected brain areas that regulate breathing. We used ionized calcium-binding-adapter molecule-1 (Iba1) immunolabeling to compare the density and morphology of microglia in the locus coeruleus (LC), the caudal medullary raphe, the caudal part of the nucleus of the tractus solitarius (cNTS), and the paraventricular nucleus of the hypothalamus (PVN). Tissue was obtained from SHAM (metaestrus) female rats or following ovariectomy. Rats were exposed to normocapnia or hypercapnia (5% CO2, 20 min). Ovariectomy and hypercapnia did not affect microglial density in any of the structures studied. Ovariectomy promoted a reactive phenotype in the cNTS and LC, as indicated by a larger morphological index. In these structures, hypercapnia had a relatively modest opposing effect; the medullary raphe or the PVN were not affected. We conclude that ovarian hormones attenuate microglial reactivity in CO2/H+ sensing structures. These data suggest that microglia may contribute to neurological diseases in which anomalies of respiratory control are associated with cyclic fluctuations of ovarian hormones or menopause.
Collapse
Affiliation(s)
- Danuzia A Marques
- Département de Pédiatrie, Centre de Recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec, Université Laval, Québec, QC, Canada.
| | - Luciane H Gargaglioni
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV at Jaboticabal, SP, Brazil
| | - Vincent Joseph
- Département de Pédiatrie, Centre de Recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec, Université Laval, Québec, QC, Canada
| | - Frédéric Bretzner
- Département de Psychiatrie et Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec, QC, Canada
| | - Kênia C Bícego
- Department of Animal Morphology and Physiology, Sao Paulo State University, UNESP/FCAV at Jaboticabal, SP, Brazil
| | - Stéphanie Fournier
- Département de Pédiatrie, Centre de Recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec, Université Laval, Québec, QC, Canada
| | - Richard Kinkead
- Département de Pédiatrie, Centre de Recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec, Université Laval, Québec, QC, Canada
| |
Collapse
|
3
|
Liu H, Allen J, Zheng D, Chen F. Recent development of respiratory rate measurement technologies. Physiol Meas 2019; 40:07TR01. [PMID: 31195383 DOI: 10.1088/1361-6579/ab299e] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Respiratory rate (RR) is an important physiological parameter whose abnormality has been regarded as an important indicator of serious illness. In order to make RR monitoring simple to perform, reliable and accurate, many different methods have been proposed for such automatic monitoring. According to the theory of respiratory rate extraction, methods are categorized into three modalities: extracting RR from other physiological signals, RR measurement based on respiratory movements, and RR measurement based on airflow. The merits and limitations of each method are highlighted and discussed. In addition, current works are summarized to suggest key directions for the development of future RR monitoring methodologies.
Collapse
Affiliation(s)
- Haipeng Liu
- Faculty of Health, Education, Medicine, and Social Care, Anglia Ruskin University, Chelmsford, CM1 1SQ, United Kingdom. Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
| | | | | | | |
Collapse
|
4
|
Abstract
The human autonomic nervous system participates in the control of thermoregulatory responses that are employed to regulate core temperature following deviations of skin temperature and/or core temperature from their respective resting values. This permits a regulation of the core temperature (TC) at 37.0 ± 1°C with superimposed circadian variations in both sexes and menstrual cycle-associated variations in premenopausal women. When rendered hyperthermic, passively by heat exposure while at rest or actively during exercise, humans engage heat loss or thermolytic responses, including eccrine sweating and cutaneous vasodilatation. A third, less studied, human thermolytic response is thermal panting, and this response is the focus of this review. Human thermal panting was first described over a century ago. It has since been shown to be a reproducible response showing some similar patterns of breathing in species that employ panting as their sole thermolytic heat loss response. The contribution of human panting as a thermolytic response, however, remains controversial. This review highlights both past and recent evidence supporting that hyperthermic humans have a panting pattern of breathing that plays an important role in human thermoregulation.
Collapse
Affiliation(s)
- Matthew D White
- Laboratory for Exercise and Environmental Physiology, Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada.
| |
Collapse
|
5
|
van der Schier R, Roozekrans M, van Velzen M, Dahan A, Niesters M. Opioid-induced respiratory depression: reversal by non-opioid drugs. F1000PRIME REPORTS 2014; 6:79. [PMID: 25343036 PMCID: PMC4173639 DOI: 10.12703/p6-79] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The human body is critically dependent on the ventilatory control system for adequate uptake of oxygen and removal of carbon dioxide (CO2). Potent opioid analgesics, through their actions on μ-opioid receptor (MOR) expressed on respiratory neurons in the brainstem, depress ventilation. Opioid-induced respiratory depression (OIRD) is potentially life threatening and the cause of substantial morbidity and mortality. One possible way of prevention of OIRD is by adding a respiratory stimulant to the opioid treatment, which through activation of non-opioidergic pathways will excite breathing and consequently will offset OIRD and should not affect analgesia. Various new respiratory stimulants are currently under investigation including (a) potassium channel blockers acting at the carotid bodies, and (b) ampakines and (c) serotonin receptor agonists acting within the brainstem. (a) GAL-021 targets BKCa-channels. Initial animal and human experimental evidence indicates that this potassium channel blocker is a potent respiratory stimulant that reverses OIRD without affecting antinociception. GAL021 is safe and better tolerated than the older K(+)-channel blocker doxapram and more efficacious in its effect on respiration. (b) Ampakines modulate glutamatergic respiratory neurons in brainstem respiratory centers. Various ampakines have been studied showing their ability to increase respiratory drive during OIRD by increasing respiratory rate. Currently, CX717 is the most promising ampakine for use in humans as it is safe and does not affect opioid analgesia. (c) While animal studies show that serotonin receptor agonists increase respiratory drive via activation of serotonin receptors in brainstem respiratory centers, human studies are without success. Further clinical studies are required to improve our care of patients that are treated with potent opioid analgesics. The use of non-opioid adjuvants may reduce the probability of OIRD but does never relieve us of our duty to continuously monitor these patients, irrespective whether they are treated in-house or in an ambulatory setting.
Collapse
Affiliation(s)
- Rutger van der Schier
- Department of Anesthesiology, Anesthesia & Pain Research Unit, Leiden University Medical CenterBuilding 1, Postzone P05-Q, P.O. Box 9600, 2300 RC LeidenThe Netherlands
| | - Margot Roozekrans
- Department of Anesthesiology, Anesthesia & Pain Research Unit, Leiden University Medical CenterBuilding 1, Postzone P05-Q, P.O. Box 9600, 2300 RC LeidenThe Netherlands
| | - Monique van Velzen
- Department of Anesthesiology, Anesthesia & Pain Research Unit, Leiden University Medical CenterBuilding 1, Postzone P05-Q, P.O. Box 9600, 2300 RC LeidenThe Netherlands
| | - Albert Dahan
- Department of Anesthesiology, Anesthesia & Pain Research Unit, Leiden University Medical CenterBuilding 1, Postzone P05-Q, P.O. Box 9600, 2300 RC LeidenThe Netherlands
| | - Marieke Niesters
- Department of Anesthesiology, Anesthesia & Pain Research Unit, Leiden University Medical CenterBuilding 1, Postzone P05-Q, P.O. Box 9600, 2300 RC LeidenThe Netherlands
| |
Collapse
|
6
|
Abstract
Respiration during sleep is determined by metabolic demand; respiratory drive is determined by a central respiratory generator. Changes in pharyngeal dilator muscle tone resulting in increased upper airway resistance and collapsibility contribute to hypoventilation. Relative hypotonia of respiratory muscles, body posture changes, and altered ventilatory control result in additional physiologic changes contributing to hypoventilation. This article reviews mechanisms of central control of respiration and normal upper and lower airway physiology. Understanding sleep-related changes in respiratory physiology will help in developing new therapies to prevent hypoventilation in susceptible populations.
Collapse
Affiliation(s)
- Mudiaga Sowho
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Johns Hopkins University, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA
| | - Jason Amatoury
- Neuroscience Research Australia, Barker Street, Randwick, New South Wales 2031, Australia; Ludwig Engel Centre for Respiratory Research, Westmead Millennium Institute, and Sydney Medical School, University of Sydney at Westmead Hospital, Hawkesbury Road, Westmead, New South Wales 2145, Australia
| | - Jason P Kirkness
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Johns Hopkins University, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA
| | - Susheel P Patil
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Johns Hopkins University, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA.
| |
Collapse
|
7
|
Dumont FS, Kinkead R. Neonatal stress and abnormal hypercapnic ventilatory response of adult male rats: The role of central chemodetection and pulmonary stretch receptors. Respir Physiol Neurobiol 2011; 179:158-66. [DOI: 10.1016/j.resp.2011.07.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 07/21/2011] [Accepted: 07/22/2011] [Indexed: 11/29/2022]
|
8
|
Hempleman SC, Pilarski JQ. Prenatal development of respiratory chemoreceptors in endothermic vertebrates. Respir Physiol Neurobiol 2011; 178:156-62. [PMID: 21569865 PMCID: PMC3146631 DOI: 10.1016/j.resp.2011.04.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2011] [Revised: 04/27/2011] [Accepted: 04/28/2011] [Indexed: 10/18/2022]
Abstract
Respiratory chemoreceptors are neurons that detect PCO(2), PO(2), and/or pH in body fluids and provide sensory feedback for the control of breathing. They play a critical role in coupling pulmonary ventilation to metabolic demand in endothermic vertebrates. During birth in mammals and hatching in birds, the state change from placental or chorioallantoic gas exchange to pulmonary respiration makes acute demands on the neonatal lungs and ventilatory control system, including the respiratory chemoreceptors. Here we review the literature on prenatal development of carotid body chemoreceptors, central chemoreceptors, and airway chemoreceptors, with emphasis on the histology, histochemistry, and neurophysiology of chemosensory cells or their afferents, and their physiological genomics if known. In general, respiratory chemoreceptors develop prenatally and are functional but immature at birth or hatching. Each type of respiratory chemoreceptor has a unique prenatal developmental time course, and all studied to date require a period of postnatal maturation to express the full adult response.
Collapse
Affiliation(s)
- Steven C Hempleman
- Department of Biology, Northern Arizona University, Flagstaff, AZ 86011-5640, USA.
| | | |
Collapse
|
9
|
Guyenet PG, Mulkey DK. Retrotrapezoid nucleus and parafacial respiratory group. Respir Physiol Neurobiol 2010; 173:244-55. [PMID: 20188865 PMCID: PMC2891992 DOI: 10.1016/j.resp.2010.02.005] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 02/09/2010] [Accepted: 02/10/2010] [Indexed: 11/26/2022]
Abstract
The rat retrotrapezoid nucleus (RTN) contains about 2000 Phox2b-expressing glutamatergic neurons (ccRTN neurons; 800 in mice) with a well-understood developmental lineage. ccRTN neuron development fails in mice carrying a Phox2b mutation commonly present in the congenital central hypoventilation syndrome. In adulthood, ccRTN neurons regulate the breathing rate and intensity, and may regulate active expiration along with other neighboring respiratory neurons. Prenatally, ccRTN neurons form an autonomous oscillator (embryonic parafacial group, e-pF) that activates and possibly paces inspiration. The pacemaker properties of the ccRTN neurons probably vanish after birth to be replaced by synaptic drives. The neonatal parafacial respiratory group (pfRG) may represent a transitional phase during which ccRTN neurons lose their group pacemaker properties. ccRTN neurons are activated by acidification via an intrinsic mechanism or via ATP released by glia. In summary, throughout life, ccRTN neurons seem to be a critical hub for the regulation of CO(2) via breathing.
Collapse
Affiliation(s)
- Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908-0735, USA.
| | | |
Collapse
|
10
|
Abstract
By definition central respiratory chemoreceptors (CRCs) are cells that are sensitive to changes in brain PCO(2) or pH and contribute to the stimulation of breathing elicited by hypercapnia or metabolic acidosis. CO(2) most likely works by lowering pH. The pertinent proton receptors have not been identified and may be ion channels. CRCs are probably neurons but may also include acid-sensitive glia and vascular cells that communicate with neurons via paracrine mechanisms. Retrotrapezoid nucleus (RTN) neurons are the most completely characterized CRCs. Their high sensitivity to CO(2) in vivo presumably relies on their intrinsic acid sensitivity, excitatory inputs from the carotid bodies and brain regions such as raphe and hypothalamus, and facilitating influences from neighboring astrocytes. RTN neurons are necessary for the respiratory network to respond to CO(2) during the perinatal period and under anesthesia. In conscious adults, RTN neurons contribute to an unknown degree to the pH-dependent regulation of breathing rate, inspiratory, and expiratory activity. The abnormal prenatal development of RTN neurons probably contributes to the congenital central hypoventilation syndrome. Other CRCs presumably exist, but the supportive evidence is less complete. The proposed locations of these CRCs are the medullary raphe, the nucleus tractus solitarius, the ventrolateral medulla, the fastigial nucleus, and the hypothalamus. Several wake-promoting systems (serotonergic and catecholaminergic neurons, orexinergic neurons) are also putative CRCs. Their contribution to central respiratory chemoreception may be behavior dependent or vary according to the state of vigilance.
Collapse
Affiliation(s)
- Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA.
| | | | | |
Collapse
|
11
|
Kinkead R, Gulemetova R. Neonatal maternal separation and neuroendocrine programming of the respiratory control system in rats. Biol Psychol 2010; 84:26-38. [DOI: 10.1016/j.biopsycho.2009.09.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 08/28/2009] [Accepted: 09/02/2009] [Indexed: 10/20/2022]
|
12
|
Gargaglioni LH, Bícegoa KC, Branco LGS. Brain monoaminergic neurons and ventilatory control in vertebrates. Respir Physiol Neurobiol 2009; 164:112-22. [PMID: 18550453 DOI: 10.1016/j.resp.2008.04.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2008] [Revised: 04/15/2008] [Accepted: 04/23/2008] [Indexed: 10/22/2022]
Abstract
Monoamines (noradrenaline (NA), adrenaline (AD), dopamine (DA) and serotonin (5-HT) are key neurotransmitters that are implicated in multiple physiological and pathological brain mechanisms, including control of respiration. The monoaminergic system is known to be widely distributed in the animal kingdom, which indicates a considerable degree of phylogenetic conservation of this system amongst vertebrates. Substantial progress has been made in uncovering the participation of the brain monoamines in the breathing regulation of mammals, since they are involved in the maturation of the respiratory network as well as in the modulation of its intrinsic and synaptic properties. On the other hand, for the non-mammalian vertebrates, most of the knowledge of central monoaminergic modulation in respiratory control, which is actually very little, has emerged from studies using anuran amphibians. This article reviews the available data on the role of brain monoaminergic systems in the control of ventilation in terrestrial vertebrates. Emphasis is given to the comparative aspects of the brain noradrenergic, adrenergic, dopaminergic and serotonergic neuronal groups in breathing regulation, after first briefly considering the distribution of monoaminergic neurons in the vertebrate brain.
Collapse
Affiliation(s)
- Luciane H Gargaglioni
- Department of Animal Morphology and Physiology, State University of Sao Paulo, FCAV at Jaboticabal, SP, Brazil.
| | | | | |
Collapse
|
13
|
Dahan A, Nieuwenhuijs D, Teppema L. Plasticity of central chemoreceptors: effect of bilateral carotid body resection on central CO2 sensitivity. PLoS Med 2007; 4:e239. [PMID: 17676946 PMCID: PMC1925127 DOI: 10.1371/journal.pmed.0040239] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Accepted: 06/11/2007] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Human breathing is regulated by feedback and feed-forward control mechanisms, allowing a strict matching between metabolic needs and the uptake of oxygen in the lungs. The most important control mechanism, the metabolic ventilatory control system, is fine-tuned by two sets of chemoreceptors, the peripheral chemoreceptors in the carotid bodies (located in the bifurcation of the common carotid arteries) and the central CO2 chemoreceptors in the ventral medulla. Animal data indicate that resection of the carotid bodies results, apart from the loss of the peripheral chemoreceptors, in reduced activity of the central CO2 sensors. We assessed the acute and chronic effect of carotid body resection in three humans who underwent bilateral carotid body resection (bCBR) after developing carotid body tumors. METHODS AND FINDINGS The three patients (two men, one woman) were suffering from a hereditary form of carotid body tumors. They were studied prior to surgery and at regular intervals for 2-4 y following bCBR. We obtained inspired minute ventilation (Vi) responses to hypoxia and CO2. The Vi-CO2 responses were separated into a peripheral (fast) response and a central (slow) response with a two-compartment model of the ventilatory control system. Following surgery the ventilatory CO2 sensitivity of the peripheral chemoreceptors and the hypoxic responses were not different from zero or below 10% of preoperative values. The ventilatory CO2 sensitivity of the central chemoreceptors decreased by about 75% after surgery, with peak reduction occurring between 3 and 6 mo postoperatively. This was followed by a slow return to values close to preoperative values within 2 y. During this slow return, the Vi-CO2 response shifted slowly to the right by about 8 mm Hg. CONCLUSIONS The reduction in central Vi-CO2 sensitivity after the loss of the carotid bodies suggests that the carotid bodies exert a tonic drive or tonic facilitation on the output of the central chemoreceptors that is lost upon their resection. The observed return of the central CO2 sensitivity is clear evidence for central plasticity within the ventilatory control system. Our data, although of limited sample size, indicate that the response mechanisms of the ventilatory control system are not static but depend on afferent input and exhibit a large degree of restoration or plasticity. In addition, the permanent absence of the breathing response to hypoxia after bCBR may aggravate the pathological consequences of sleep-disordered breathing.
Collapse
Affiliation(s)
- Albert Dahan
- Department of Anesthesiology, Leiden University Medical Center, Leiden, The Netherlands.
| | | | | |
Collapse
|
14
|
Rosin DL, Chang DA, Guyenet PG. Afferent and efferent connections of the rat retrotrapezoid nucleus. J Comp Neurol 2006; 499:64-89. [PMID: 16958085 DOI: 10.1002/cne.21105] [Citation(s) in RCA: 201] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The rat retrotrapezoid nucleus (RTN) contains candidate central chemoreceptors that have extensive dendrites within the marginal layer (ML). This study describes the axonal projections of RTN neurons and their probable synaptic inputs. The ML showed a dense plexus of nerve terminals immunoreactive (ir) for markers of glutamatergic (vesicular glutamate transporters VGLUT1-3), gamma-aminobutyric acid (GABA)-ergic, adrenergic, serotonergic, cholinergic, and peptidergic transmission. The density of VGLUT3-ir terminals tracked the location of RTN chemoreceptors. The efferent and afferent projections of RTN were studied by placing small iontophoretic injections of anterograde (biotinylated dextran amine; BDA) and retrograde (cholera toxin B) tracers where RTN chemoreceptors have been previously recorded. BDA did not label the nearby C1 cells. BDA-ir varicosities were found in the solitary tract nucleus (NTS), all ventral respiratory column (VRC) subdivisions, A5 noradrenergic area, parabrachial complex, and spinal cord. In each target region, a large percentage of the BDA-ir varicosities was VGLUT2-ir (41-83%). Putative afferent input to RTN originated from spinal cord, caudal NTS, area postrema, VRC, dorsolateral pons, raphe nuclei, lateral hypothalamus, central amygdala, and insular cortex. The results suggest that 1) whether or not the ML is specialized for CO(2) sensing, its complex neuropil likely regulates the activity of RTN chemosensitive neurons; 2) the catecholaminergic, cholinergic, and serotonergic innervation of RTN represents a possible substrate for the known state-dependent control of RTN chemoreceptors; 3) VGLUT3-ir terminals are a probable marker of RTN; and 4) the chemosensitive neurons of RTN may provide a chemical drive to multiple respiratory outflows, insofar as RTN innervates the entire VRC.
Collapse
Affiliation(s)
- Diane L Rosin
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA.
| | | | | |
Collapse
|
15
|
Abstract
The pattern of breathing during a hyperthermia-induced hyperventilation varies across different species. Thermal tachypnea is a first phase panting response adopted during hyperthermia when tidal volume is minimized and the frequency of breathing is maximized. Blood-gas tensions and pH are maintained during this hyperventilation, and the associated heat loss helps the animal regulate its body temperature. A second pattern of breathing adopted in hyperthermia is thermal hyperpnea; this response is the focus of this review. This form of hyperventilation is evident after an increase in core temperature and it is apparent in humans. Increases of tidal volume as well as frequency of breathing are evident during this response that results in a respiratory alkalosis. The cause of thermal hyperpnea is not resolved; evidence of the potential mechanisms underlying this response support that modulators of the response act in either a multiplicative or additive manner with body temperatures. The details of the designs and methodologies of the studies supporting or refuting these two views are discussed. A physiological rationale for thermal hyperpnea is presented in which it is suggested this response serves a heat-loss role and contributes to selective brain cooling in hyperthermic humans. Ongoing research in this area is focused on resolving the mechanisms underlying thermal hyperpnea and its contribution to cranial thermoregulation. The direct application of this research is for the care of febrile and hyperthermic patients.
Collapse
Affiliation(s)
- Matthew D White
- Laboratory for Exercise and Environmental Physiology, 8888 University Dr., School of Kinesiology, Simon Fraser Univ., Burnaby, British Columbia, Canada V5A 1S6.
| |
Collapse
|
16
|
Niblock MM, Luce CJ, Belliveau RA, Paterson DS, Kelly ML, Sleeper LA, Filiano JJ, Kinney HC. Comparative anatomical assessment of the piglet as a model for the developing human medullary serotonergic system. ACTA ACUST UNITED AC 2005; 50:169-83. [PMID: 16043226 DOI: 10.1016/j.brainresrev.2005.05.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2005] [Revised: 05/10/2005] [Accepted: 05/13/2005] [Indexed: 10/25/2022]
Abstract
Because the piglet is frequently used as a model for developmental disorders of the medullary serotonergic (5-HT) system in the human infant, this review compares the topography and developmental profile of selected 5-HT markers between humans in the first year of life and piglets in the first 60 days of life. The distribution of tryptophan hydroxylase-immunoreactive 5-HT neurons in the human infant medulla is very similar, but not identical, to that in the piglet. One notable difference is the presence of compact clusters of 5-HT neurons at the ventral surface of the piglet medulla. While it lacks these distinctive clusters, the human infant medulla contains potentially homologous 5-HT neurons scattered along the ventral surface embedded in the arcuate nucleus. Each species shows evidence of age-related changes in the 5-HT system, but the changes are different in nature; in the human infant, statistically significant age-related changes are observed in the proportional distribution of medullary 5-HT cells, while in the piglet, statistically significant age-related changes are observed in the levels of 5-HT receptor binding in certain medullary nuclei. Analyses of 5-HT receptor binding profiles in selected nuclei in the two species suggest that the equivalent postnatal ages for 5-HT development in piglets and human infants are, respectively, 4 days and 1 month, 12 days and 4 months, 30 days and 6 months, and 60 days and 12 months. Collectively, when certain species differences are considered, these data support the use of the piglet as a model for the human infant medullary 5-HT system.
Collapse
Affiliation(s)
- Mary M Niblock
- Department of Physiology, Dartmouth Medical School, 1 Medical Center Drive, Lebanon, NH 03756, USA.
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Ritucci NA, Erlichman JS, Leiter J, Putnam RW. Response of membrane potential and intracellular pH to hypercapnia in neurons and astrocytes from rat retrotrapezoid nucleus. Am J Physiol Regul Integr Comp Physiol 2005; 289:R851-61. [PMID: 15905224 PMCID: PMC1201380 DOI: 10.1152/ajpregu.00132.2005] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We compared the response to hypercapnia (10%) in neurons and astrocytes among a distinct area of the retrotrapezoid nucleus (RTN), the mediocaudal RTN (mcRTN), and more intermediate and rostral RTN areas (irRTN) in medullary brain slices from neonatal rats. Hypercapnic acidosis (HA) caused pH(o) to decline from 7.45 to 7.15 and a maintained intracellular acidification of 0.15 +/- 0.02 pH unit in 90% of neurons from both areas (n = 16). HA excited 44% of mcRTN (7/16) and 38% of irRTN neurons (6/16), increasing firing rate by 167 +/- 75% (chemosensitivity index, CI, 256 +/- 72%) and 310 +/- 93% (CI 292 +/- 50%), respectively. These responses did not vary throughout neonatal development. We compared the responses of mcRTN neurons to HA (decreased pH(i) and pH(o)) and isohydric hypercapnia (IH; decreased pH(i) with constant pH(o)). Neurons excited by HA (firing rate increased 156 +/- 46%; n = 5) were similarly excited by IH (firing rate increased 167 +/- 38%; n = 5). In astrocytes from both RTN areas, HA caused a maintained intracellular acidification of 0.17 +/- 0.02 pH unit (n = 6) and a depolarization of 5 +/- 1 mV (n = 12). In summary, many neurons (42%) from the RTN are highly responsive (CI 248%) to HA; this may reflect both synaptically driven and intrinsic mechanisms of CO(2) sensitivity. Changes of pH(i) are more significant than changes of pH(o) in chemosensory signaling in RTN neurons. Finally, the lack of pH(i) regulation in response to HA suggests that astrocytes do not enhance extracellular acidification during hypercapnia in the RTN.
Collapse
Affiliation(s)
- Nick A. Ritucci
- Department of Neuroscience, Cell Biology and Physiology, Wright State University School of Medicine, 3640 Colonel Glenn Highway, Dayton, OH 45435
| | - Joseph S. Erlichman
- Department of Biology, St. Lawrence University, 10 Ramoda Drive, Canton, N.Y. 13627; and
| | - J.C. Leiter
- Department of Physiology, Dartmouth Medical School, One Medical Center Drive, Lebanon, N.H. 03756
| | - Robert W. Putnam
- Department of Neuroscience, Cell Biology and Physiology, Wright State University School of Medicine, 3640 Colonel Glenn Highway, Dayton, OH 45435
| |
Collapse
|
18
|
Richerson GB, Wang W, Hodges MR, Dohle CI, Diez‐Sampedro A. Homing in on the specific phenotype(s) of central respiratory chemoreceptors. Exp Physiol 2005. [DOI: 10.1111/j.1469-445x.2005.tb00002.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- G. B. Richerson
- Departments of Neurology and Cellular & Molecular PhysiologyYale University School of MedicineNew HavenCTUSA
- Veteran's Affairs Medical CenterWest HavenCTUSA
- NeurologyLCI‐712, 15 York St, PO 208018New HavenCT06520‐8018USA
| | - W. Wang
- Departments of Neurology and Cellular & Molecular PhysiologyYale University School of MedicineNew HavenCTUSA
| | - M. R. Hodges
- Departments of Neurology and Cellular & Molecular PhysiologyYale University School of MedicineNew HavenCTUSA
| | - C. I. Dohle
- Departments of Neurology and Cellular & Molecular PhysiologyYale University School of MedicineNew HavenCTUSA
| | - A. Diez‐Sampedro
- Departments of Neurology and Cellular & Molecular PhysiologyYale University School of MedicineNew HavenCTUSA
| |
Collapse
|
19
|
Guyenet PG, Stornetta RL, Bayliss DA, Mulkey DK. Re: Homing in on the specific phenotype(s) of central respiratory chemoreceptors. Exp Physiol 2005. [DOI: 10.1111/j.1469-445x.2005.t01-1-00135.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
20
|
Guyenet PG, Stornetta RL, Bayliss DA, Mulkey DK. Retrotrapezoid nucleus: a litmus test for the identification of central chemoreceptors. Exp Physiol 2005. [DOI: 10.1111/j.1469-445x.2005.t01-1-00134.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
21
|
Guyenet PG, Stornetta RL, Bayliss DA, Mulkey DK. Retrotrapezoid nucleus: a litmus test for the identification of central chemoreceptors. Exp Physiol 2005. [DOI: 10.1111/j.1469-445x.2005.tb00022.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Patrice G. Guyenet
- Department of PharmacologyUniversity of VirginiaCharlottesvilleVA22908USA
| | - Ruth L. Stornetta
- Department of PharmacologyUniversity of VirginiaCharlottesvilleVA22908USA
| | - Douglas A. Bayliss
- Department of PharmacologyUniversity of VirginiaCharlottesvilleVA22908USA
| | - Daniel K. Mulkey
- Department of PharmacologyUniversity of VirginiaCharlottesvilleVA22908USA
| |
Collapse
|
22
|
Guyenet PG, Stornetta RL, Bayliss DA, Mulkey DK. Re: Homing in on the specific phenotype(s) of central respiratory chemoreceptors. Exp Physiol 2005. [DOI: 10.1113/expphysiol.2004.029843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Patrice G. Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Ruth L. Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Douglas A. Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Daniel K. Mulkey
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| |
Collapse
|