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Chemoreflex

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https://www.readbyqxmd.com/read/28416458/on-the-origins-of-sex-based-differences-in-respiratory-disorders-lessons-and-hypotheses-from-stress-neuroendocrinology-in-developing-rats
#1
REVIEW
Jean-Philippe Rousseau, Luana Tenorio-Lopes, Cécile Baldy, Tara Adele Janes, Stéphanie Fournier, Richard Kinkead
The environment plays a critical role in shaping development and function of the brain. Stress, especially when experienced early in life, can interfere with these processes. In the context of respiratory control, perinatal stress can therefore alter the ability to achieve the "fine-tuning" necessary for proper detection of chemosensory stimuli and production of an adequate motor (respiratory) command. Depending on the timing, intensity, and duration, the detrimental consequences of perinatal exposure to adverse conditions on the respiratory network become manifest at various life stages and can persist into adulthood...
April 14, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28404583/acute-hypoxia-activates-neuroendocrine-but-not-pre-sympathetic-neurons-in-the-paraventricular-nucleus-of-the-hypothalamus-differential-role-of-nitric-oxide
#2
K Max Coldren, De-Pei Li, David D Kline, Eileen M Hasser, Cheryl M Heesch
Hypoxia results in decreased arterial PO2, arterial chemoreflex activation, and compensatory increases in breathing, sympathetic outflow, and neuroendocrine secretions, including increased secretion of vasopressin (AVP), corticotropin releasing hormone (CRH), adrenocorticotropin hormone (ACTH), and corticosterone. In addition to a brainstem pathway including the nucleus tractus solitarius (nTS) and the rostral ventrolateral medulla (RVLM), medullary pathways to the paraventricular nucleus of the hypothalamus (PVN) contribute to chemoreflex responses...
April 12, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/28343606/respiratory-muscles-and-chemoreflex-sensitivity-in-heart-failure-a-breath-of-fresh-air
#3
EDITORIAL
Richard Severin, Shane A Phillips
No abstract text is available yet for this article.
April 2017: Canadian Journal of Cardiology
https://www.readbyqxmd.com/read/28323007/inhibition-of-microglial-activation-with-minocycline-at-the-intrathecal-level-attenuates-sympathoexcitatory-and-proarrhythmogenic-changes-in-rats-with-chronic-temporal-lobe-epilepsy
#4
Amol M Bhandare, Komal Kapoor, Kim L Powell, Emma Braine, Pablo Casillas-Espinosa, Terence J O'Brien, Melissa M J Farnham, Paul M Pilowsky
The incidence of sudden unexpected death in epilepsy (SUDEP) is highest in people with chronic and drug-resistant epilepsy. Chronic spontaneous recurrent seizures cause cardiorespiratory autonomic dysfunctions. Pituitary adenylate cyclase-activating polypeptide (PACAP) is neuroprotective, whereas microglia produce both pro- and anti-inflammatory effects in the CNS. During acute seizures in rats, PACAP and microglia produce sympathoprotective effect at the intermediolateral cell column (IML), whereas their action on the presympathetic rostral ventrolateral medulla (RVLM) neurons mediates proarrhythmogenic changes...
March 18, 2017: Neuroscience
https://www.readbyqxmd.com/read/28288844/forced-vital-capacity-and-not-central-chemoreflex-predicts-maximal-hyperoxic-breath-hold-duration-in-elite-apneists
#5
Anthony R Bain, Otto F Barak, Ryan L Hoiland, Ivan Drvis, Damian M Bailey, Zeljko Dujic, Tanja Mijacika, Antoinette Santoro, Daniel K DeMasi, David B MacLeod, Philip N Ainslie
The determining mechanisms of a maximal hyperoxic apnea duration in elite apneists have remained unexplored. We tested the hypothesis that maximal hyperoxic apnea duration in elite apneists is related to forced vital capacity (FVC) but not the central chemoreflex (for CO2). Eleven elite apneists performed a maximal dry static-apnea with prior hyperoxic (100% oxygen) pre-breathing, and a central chemoreflex test via a hyperoxic re-breathing technique (hyperoxic-hypercapnic ventilatory response: HCVR); expressed as the increase in ventilation (pneumotachometry) per increase in arterial CO2 tension (PaCO2; radial artery)...
March 11, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28279732/intra-individual-variability-in-cerebrovascular-and-respiratory-chemosensitivity-can-we-characterize-a-chemoreflex-reactivity-profile
#6
Kennedy J Borle, Jamie R Pfoh, Lindsey M Boulet, Maria Abrosimova, Michael M Tymko, Rachel J Skow, Amy Varner, Trevor A Day
Intra-individual variability in the magnitude of human cerebrovascular and respiratory chemoreflex responses is largely unexplored. By comparing response magnitudes of cerebrovascular CO2 reactivity (CVR; middle and posterior cerebral arteries; MCA, PCA), central (CCR; CO2) and peripheral respiratory chemoreflexes (PCR; CO2 and O2), we tested the hypothesis that a within-individual reactivity magnitude profile could be characterized. The magnitudes of CVR and CCR were tested with hyperoxic rebreathing and PCR magnitudes were tested through transient respiratory tests (TT-CO2, hypercapnia; TT-N2, hypoxia)...
March 6, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28251147/the-influence-of-age-on-interaction-between-breath-holding-test-and-single-breath-carbon-dioxide-test
#7
Nikita Trembach, Igor Zabolotskikh
Introduction. The aim of the study was to compare the breath-holding test and single-breath carbon dioxide test in evaluation of the peripheral chemoreflex sensitivity to carbon dioxide in healthy subjects of different age. Methods. The study involved 47 healthy volunteers between ages of 25 and 85 years. All participants were divided into 4 groups according to age: 25 to 44 years (n = 14), 45 to 60 years (n = 13), 60 to 75 years (n = 12), and older than 75 years (n = 8). Breath-holding test was performed in the morning before breakfast...
2017: BioMed Research International
https://www.readbyqxmd.com/read/28215596/sex-specific-respiratory-effects-of-acute-and-chronic-caffeine-administration-in-newborn-rats
#8
REVIEW
Hayet Kouchi, NagaPraveena Uppari, Vincent Joseph, Aida Bairam
Caffeine is widely used for the treatment of apnea of prematurity (AoP) but whether this effect varies with sex is unknown. To shed some light on this question, we present a summary of data obtained on the effects of caffeine on the respiratory chemoreflexes and apnea frequency in 1- and 12-days old male and female rats. Caffeine was either administered as a single acute injection (10mg/kg, i.p.) or for 10 consecutive days (7.5mg/kg/day between 3 and 12days of life by gavage, simulating its clinical use). Acute caffeine had little effects on breathing in 1-day old male and female rats...
February 16, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28188852/the-k%C3%A3-lliker-fuse-nucleus-acts-as-a-timekeeper-for-late-expiratory-abdominal-activity
#9
Sarah E M Jenkin, William K Milsom, Daniel B Zoccal
While the transition from the inspiratory to the post-inspiratory (post-I) phase is dependent on the pons, little attention has been paid to understanding the role of the pontine respiratory nuclei, specifically the Kölliker-Fuse nucleus (KF), in transitioning from post-I to the late expiratory (late-E) activity seen with elevated respiratory drive. To elucidate this, we used the in situ working heart-brainstem preparation of juvenile male Holtzman rats and recorded from the vagus (cVN), phrenic (PN) and abdominal nerves (AbN) during baseline conditions and during chemoreflex activation [with potassium cyanide (KCN; n=13) or hypercapnia (8% CO2; n=10)] to recruit active expiration...
February 8, 2017: Neuroscience
https://www.readbyqxmd.com/read/28181258/cardiac-diastolic-and-autonomic-dysfunction-are-aggravated-by-central-chemoreflex-activation-in-heart-failure-with-preserved-ejection-fraction-rats
#10
Camilo Toledo, David C Andrade, Claudia Lucero, Alexis Arce-Alvarez, Hugo S Díaz, Valentín Aliaga, Harold D Schultz, Noah J Marcus, Mónica Manríquez, Marcelo Faúndez, Rodrigo Del Rio
KEY POINTS: Heart failure with preserved ejection fraction (HFpEF) is associated with disordered breathing patterns, and sympatho-vagal imbalance. Although it is well accepted that altered peripheral chemoreflex control plays a role in the progression of heart failure with reduced ejection fraction (HFrEF), the pathophysiological mechanisms underlying deterioration of cardiac function in HFpEF are poorly understood. We found that central chemoreflex is enhanced in HFpEF and neuronal activation is increased in pre-sympathetic regions of the brainstem...
April 15, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28177673/interleukin-1beta-suppresses-the-ventilatory-hypoxic-response-in-rats-via-prostaglandin-dependent-pathways
#11
Nina Pavlovna Aleksandrova, Galina Anatol'yevna Danilova, Vjacheslav Georgievich Aleksandrov
We investigated the effect of the major inflammatory cytokine interleukin-1beta (IL-1β) on the ventilatory response to hypoxia. The goal was to test the hypothesis that IL-1β impairs the hypoxic ventilatory response in vivo by indirectly inhibiting respiratory neurons in the brainstem via prostaglandins. Thus, IL-1β was delivered by cerebroventricular injection, and the ventilatory hypoxic response was assessed in anesthetized, spontaneously breathing rats pretreated with or without diclofenac, a nonspecific inhibitor of prostaglandin synthesis...
January 22, 2017: Canadian Journal of Physiology and Pharmacology
https://www.readbyqxmd.com/read/28132741/respiratory-muscle-training-improves-chemoreflex-response-heart-rate-variability-and-respiratory-mechanics-in-rats-with-heart-failure
#12
Rodrigo B Jaenisch, Edson Quagliotto, Chalyne Chechi, Leonardo Calegari, Fernando Dos Santos, Audrey Borghi-Silva, Pedro Dal Lago
BACKGROUND: The aim of the present report was to evaluate respiratory muscle training (RMT) effects on hemodynamic function, chemoreflex response, heart rate variability, and respiratory mechanics in rats with heart failure (HF rats). METHODS: Wistar rats were divided into 4 groups: sedentary-sham (Sed-Sham, n = 8), respiratory muscle trained-sham (RMT-Sham, n = 8), sedentary-HF (Sed-HF, n = 8) and respiratory muscle trained-HF (RMT-HF, n = 8). Animals were submitted to an RMT protocol performed 30 minutes per day, 5 days per week for 6 weeks, whereas the sedentary animals did not exercise...
November 11, 2016: Canadian Journal of Cardiology
https://www.readbyqxmd.com/read/28106557/blunted-respiratory-responses-in%C3%A2-the%C3%A2-streptozotocin-induced-alzheimer-s-disease-rat-model
#13
Dalton L Ebel, Christopher G Torkilsen, Tim D Ostrowski
Alzheimer's disease (AD) is known for the progressive decline of cognition and memory. In addition to these disease-defining symptoms, impairment of respiratory function is frequently observed and often expressed by sleep-disordered breathing or reduced ability to adjust respiration when oxygen demand is elevated. The mechanisms for this are widely unknown. Postmortem analysis from the brainstem of AD patients reveals pathological alterations, including in nuclei responsible for respiratory control. In this study, we analyzed respiratory responses and morphological changes in brainstem nuclei following intracerebroventricular (ICV) injections of streptozotocin (STZ), a rat model commonly used to mimic sporadic AD...
January 20, 2017: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/28073937/activity-of-tachykinin1-expressing-pet1-raphe-neurons-modulates-the-respiratory-chemoreflex
#14
Morgan L Hennessy, Andrea E Corcoran, Rachael D Brust, YoonJeung Chang, Eugene E Nattie, Susan M Dymecki
Homeostatic control of breathing, heart rate, and body temperature relies on circuits within the brainstem modulated by the neurotransmitter serotonin (5-HT). Mounting evidence points to specialized neuronal subtypes within the serotonergic neuronal system, borne out in functional studies, for the modulation of distinct facets of homeostasis. Such functional differences, read out at the organismal level, are likely subserved by differences among 5-HT neuron subtypes at the cellular and molecular levels, including differences in the capacity to coexpress other neurotransmitters such as glutamate, GABA, thyrotropin releasing hormone, and substance P encoded by the Tachykinin-1 (Tac1) gene...
February 15, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28070480/central-congenital-hypoventilation-syndrome-associated-with-hypoglycemia-and-seizure
#15
Emily Hopkins, James Stark, Ricardo A Mosquera
Central Congenital Hypoventilation Syndrome (CCHS) is a rare diagnosis that presents with various forms of autonomic dysfunction. The disease is characterized by reduced chemoreflexes and severe hypoventilation during sleep. Several case reports have noted that patients with CCHS have been found to suffer from hypoglycemic episodes, which frequently present as a seizure. In this report, we will review previous case presentations to alert the physicians about this association with hypoglycemic episodes. Early treatment and monitoring of hypoglycemia will prevent further complications for these populations...
2017: Respiratory Medicine Case Reports
https://www.readbyqxmd.com/read/28065687/restless-legs-syndrome-and-cardiovascular-disease-a-research-roadmap
#16
REVIEW
Daniel J Gottlieb, Virend K Somers, Naresh M Punjabi, John W Winkelman
In this paper, we first critically appraise the epidemiologic literature examining the association of restless legs syndrome (RLS) with cardiovascular disease (CVD) and then consider whether lessons learned from the study of cardiovascular consequences of other sleep disorders might inform a research agenda to examine the potential mechanisms of cardiovascular morbidity of RLS. Cross-sectional and longitudinal studies are both mixed as to whether there is a meaningful association of RLS and CVD. On the other hand, numerous cross-sectional and longitudinal observational studies have shown a strong association of obstructive sleep apnea (OSA) with CVD risk...
March 2017: Sleep Medicine
https://www.readbyqxmd.com/read/28062485/activation-of-bitter-taste-receptors-in-pulmonary-nociceptors-sensitizes-trpv1-channels-through-plc-and-pkc-signaling-pathway
#17
Qihai Gu, Deanna S Joe, Carolyn A Gilbert
Bitter taste receptors (T2Rs), a G-protein-coupled receptor family capable of detecting numerous bitter-tasting compounds, have recently been shown to be expressed and play diverse roles in many extraoral tissues. Here we report the functional expression of T2Rs in rat pulmonary sensory neurons. In anesthetized spontaneously breathing rats, intratracheal instillation of T2Rs agonist chloroquine (10 mM, 0.1 ml) significantly augmented chemoreflexes evoked by right-atrial injection of capsaicin, a specific activator for transient receptor potential vanilloid receptor 1 (TRPV1); whereas intravenous infusion of chloroquine failed to significantly affect capsaicin-evoked reflexes...
January 6, 2017: American Journal of Physiology. Lung Cellular and Molecular Physiology
https://www.readbyqxmd.com/read/28039190/endurance-training-attenuates-the-increase-in-peripheral-chemoreflex-sensitivity-with-intermittent-hypoxia
#18
Amanda J Miller, Charity L Sauder, Aimee E Cauffman, Cheryl A Blaha, Urs A Leuenberger
Patients with heart failure and sleep apnea have greater chemoreflex sensitivity, presumably due to intermittent hypoxia (IH), and this is predictive of mortality. We hypothesized that endurance training would attenuate the effect of IH on peripheral chemoreflex sensitivity in healthy humans. Fifteen young healthy subjects (9 female, 26 ± 1 yr) participated. Between visits, 11 subjects underwent 8 wk of endurance training that included running four times/wk at 80% predicted maximum heart rate and interval training, and four control subjects did not change activity...
February 1, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/27906839/endothelin-contributes-to-the-blood-pressure-rise-triggered-by-hypoxia-in-severe-obstructive-sleep-apnea
#19
Christophe Janssen, Atul Pathak, Guido Grassi, Philippe van de Borne
BACKGROUND: Obstructive sleep apnea (OSA) is strongly correlated with an increased risk of systemic hypertension. However, the link between systemic hypertension and nocturnal apneas remains incompletely understood. Animal studies suggest an implication of the endothelin system. The aim of the present study is to determine if endogenous endothelin plays a role in the increase in blood pressure observed during hypoxic episodes in OSA patients, in addition to peripheral chemoreflex and neural sympathetic activation...
January 2017: Journal of Hypertension
https://www.readbyqxmd.com/read/27861919/consequences-of-maternal-omega-3-polyunsaturated-fatty-acid-supplementation-on-respiratory-function-in-rat-pups
#20
Luana Tenorio-Lopes, Cécile Baldy, Alexandra Jochmans-Lemoine, Océane Mercier, Olivier Pothier-Piccinin, Tommy Seaborn, Vincent Joseph, Isabelle Marc, Richard Kinkead
KEY POINTS: Incomplete development of the neural circuits that control breathing contributes to respiratory disorders in pre-term infants. Manifestations include respiratory instability, prolonged apnoeas and poor ventilatory responses to stimuli. Based on evidence suggesting that omega-3 polyunsaturated fatty acids (n-3 PUFA) improves brain development, we determined whether n-3 PUFA supplementation (via the maternal diet) improves respiratory function in 10-11-day-old rat pups. n-3 PUFA treatment prolonged apnoea duration but augmented the relative pulmonary surface area and the ventilatory response to hypoxia...
November 11, 2016: Journal of Physiology
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