Changes In Respiratory Frequency Research Articles

A novel sensible smart mask using micro thermal-electric energy conversion elements

With the improvement of people’s living standards, more and more people begin to pay attention to their own health status. The mode of monitoring human physiological indicators is gradually shifting to a family-based and miniaturized development model that focuses on prevention. Respiratory rate is an important parameter that reflects the health status of the human body. It is an important diagnostic basis for doctors in clinical prevention and diagnosis of related diseases. Therefore, it is necessary to develop a portable monitoring instrument that can dynamically monitor the human respiratory frequency index in real time. Since most of the existing wearable respiratory frequency detection devices have some disadvantages such as low accuracy, high cost and difficulty in promotion, this paper proposes a new type of smart mask based on thermoelectric effect to monitor human respiratory frequency in real time. The respirator system has the advantages of small size, light weight and suitable for face. Compared with other heavy breathing devices, it has obvious advantages. The Seebeck effect of thermoelectric energy conversion element (TECE) can be used to reflect the respiratory frequency of human body under different respiratory conditions. Experiments show that the sensor has high accuracy and can accurately reflect even small changes in respiratory frequency.

The toxicity assessment of neorudin in cynomolgus monkeys.

In this study, the toxicity effects on circulatory system and respiratory system, and the acute toxicity test of recombinant neorudin (EPR-hirudin, EH) in cynomolgus monkeys were evaluated to provide reference information for clinical studies. Eighteen cynomolgus monkeys were randomly divided into three groups for single intravenous administration of 3, 30 mg/kg EH and normal saline, respectively. The changes of respiratory frequency, respiratory intensity, blood pressure and electrocardiogram before and after administration were recorded. In acute toxicity test, six cynomolgus monkeys were intravenously received EH at a single dose of 171, 257, 385, 578, 867 and 1300 mg/kg respectively. The vital signs, hematology, serum biochemistry, coagulation indexes and electrocardiogram indexes of the animals were determined before administration and on the 7th and 14th day after administration. As the results showed that there were no significant abnormal changes in respiratory frequency, respiratory intensity, blood pressure or electrocardiogram in cynomolgus monkeys after receiving EH at 3 mg/kg and 30 mg/kg, and there was no statistical difference between the treated groups and normal saline group. In the acute toxicity test, no significant abnormalities were observed in vital signs, hematology, serum biochemistry, coagulation indexes and electrocardiogram indexes of six cynomolgus monkeys at day 7 and 14 after EH administration. Furthermore, autopsies of all cynomolgus monkeys showed no abnormalities. The results of toxicokinetics showed that AUClast of the drug increased in proportion to the EH dose in the range of 171-578 mg/kg, and increased in over proportion to the EH dose in the range of 578-1300 mg/kg. The variation of Cmax was basically consistent with AUClast. In a sum, A single intravenous injection of 3 and 30 mg/kg of EH did not affect the circulatory system and respiratory system in cynomolgus monkeys and the maximum tolerated dose of EH in cynomolgus monkey is over 1300 mg/kg (equivalent to 619-1300 times of the proposed clinical equivalent dose).

Stamina Prediction of Cows and Goats to Exercise Changes by Measuring Body Temperature, Heart Rate, and Respiratory Rate

Environmental factors play an important role in livestock life. An unsuitable environment can cause disturbances to the growth of animal and cannot produce properly. The purpose of this study was to determine changes in respiratory frequency, heart rate and body temperature of cows and goats at rest, when given running training, and when a rest one hour after being rushed, to find out the stamina of the animals. The results showed that exercise treatment had a very significant effect on respiratory rate, body temperature, and heart rate. The respiratory rate after exercise was significantly different from the respiratory frequency before exercise and after resting for one hour, but quickly returned to normal after one hour rest which indicates that the stamina of these two animals is very good.

Assessing stress variations in children during the strange situation procedure: comparison of three widely used respiratory sinus arrhythmia estimation methods

Objective. The respiratory sinus arrhythmia (RSA) is a well-known marker of vagal activity that can be exploited to measure stress changes. RSA is usually estimated from heart rate variability (HRV). This study aims to compare the RSA obtained with three widely adopted methods showing their strengths and potential pitfalls. Approach. The three methods are tested on 69 healthy preschoolers undergoing a stressful protocol, the strange situation procedure (SSP). We compare the RSA estimated by the Porges method, the univariate autoregressive (AR) spectral analysis of the HRV signal, and the bivariate AR spectral analysis of HRV and respirogram signals. We examine RSA differences detected across the SSP episodes and correlation between the estimates provided by each method. Main results. The Porges and the bivariate AR approaches both detected significant differences (i.e. stress variations) in the RSA measured across the SSP. However, the latter method showed higher sensitivity to stress changes induced by the procedure, with the mean RSA variation between baseline and first separation from the mother (the most stressful condition) being significantly different among methods: Porges, −17.5%; univariate AR, −18.3%; bivariate AR, −23.7%. Moreover, the performances of the Porges algorithm were found strictly dependent on the applied preprocessing. Significance. Our findings confirm the bivariate AR analysis of the HRV and respiratory signals as a robust stress assessment tool that does not require any population-specific preprocessing of the signals and warn about using RSA estimates that neglect breath information in more natural experiments, such as those involving children, in which respiratory frequency changes are extremely likely.

Differential Respiratory Effects of µ‐opioid Receptor Activation within the preBötzinger Complex and Neighbouring Respiration‐related Regions in the Rabbit

It is well known that opioids induce respiratory depression by activating µ-opioid receptors (MORs). Although MORs are expressed throughout the entire brainstem respiratory network, the effects of their activation within the different respiration-related regions are still unclear. We investigated the contribution of the preBötzinger Complex (preBötC) and the neighbouring Bötzinger Complex (BötC) and inspiratory portion of the ventral respiratory group (iVRG) to the MOR-induced respiratory depression in anesthetized, vagotomized, paralyzed and artificially ventilated adult rabbits making use of microinjections (30-50 nl) of the MOR agonist [D-Ala2, N-Me-Phe4, Gly5-ol]-enkephalin (DAMGO). Dose-dependent effects were observed. DAMGO microinjected at 0.1 mM into the preBötC and the BötC caused progressive reductions in peak phrenic amplitude associated with tonic phrenic activity and patterns of breathing displaying irregularities that were more marked in the preBötC (ataxic breathing). Increases or no changes in respiratory frequency accompanied these responses in the preBötC and the BötC, respectively. Tonic apneic effects developed at 0.5 mM. DAMGO microinjected into the iVRG provoked decreases in the amplitude and frequency of phrenic bursts at 0.1 mM and apnea at 0.5 mM. DAMGO-induced increases in the variability of peak phrenic amplitude and time components of the breathing pattern were more pronounced after microinjections into the preBötC. Local application of 5 mM naloxone reversed the apneic effects in all instances. The results provide further insides into the role of MORS in the genesis of respiratory depression induced by systemically administered opioids. They suggest that various areas of the respiratory network differentially contribute to the opioid-induced respiratory disorders and support the view that the preBötC may play a prominent role.

PENGARUH KANDANG NAUNGAN DAN TANPA NAUNGAN TERHADAP FREKUENSI PERNAFASAN DAN SUHU TUBUH KAMBING KACANG JANTAN DI LAHAN KERING KEPULAUAN

The temperature of the environment outside the body increases, especially cattle, goats that are kept in cages without shade will cause manifestations of these reactions, namely increased frequency of respiration and body temperature and behavior that shows heat. The purpose of this study was to compare changes in respiratory frequency and body temperature of goat nuts, which were shaded with shade and without shade on the island's dry land. This study used fourteen 14 years old male goats. those goats are placed in 7 roofed cages and 7 cages without roof. The study was conducted for 30 days. The variables observed were respiratory frequency and body temperature. The analysis of the results of the study was carried out by t-student test by comparing the goat's breeds in cages with shade and cages without shade. The results of the t-test analysis show that the effect of roofed cages and without roof does not give a difference in respiratory frequency and body temperature. Goats raised in Kupang have implemented for a long time, both in the atmosphere of the cage with roof and without, so that goats have experienced acclimatization, which is a long-term physiological adjustment that causes increased tolerance to stressful complex and continuous climate which usually occurs in the field. This is the basis that the respiratory frequency and body temperature of the goats kept in a roofed stall and without, do not have a significant effect. It can be concluded that shade cages and without shade do not affect respiratory frequency and body temperature.

Feasibility of Exercise Testing in Patients Who Are Critically Ill: A Prospective, Observational Multicenter Study

ObjectiveTo evaluate the feasibility and safety of exercise testing and to describe the physiological response to exercise of patients in the Intensive Care Unit (ICU). DesignA prospective observational multicenter study. SettingTwo mixed medical-surgical ICUs. ParticipantsPatients (N=37; with no primary neurological disorders, 59% men; median age 50y; ICU length of stay 14.5d; Acute Physiology and Chronic Health Evaluation IV 73.0) who had been mechanically ventilated for more than 48 hours and were hemodynamically stable enough to perform physical exercise. InterventionsA passive or active incremental exercise test, depending on muscle strength, on a bed-based cycle ergometer. Main Outcome MeasuresFeasibility and safety were evaluated based on protocol adherence and adverse events. Physiological responses to exercise quantified as changes in respiratory frequency (RF), oxygen uptake (Vo2), carbon dioxide output (Vco2), respiratory exchange ratio (RER), and blood lactate. ResultsThirty-seven patients of whom 18 were mechanically ventilated underwent the exercise test. The active incremental test was performed by 28, and the passive test by 9 participants. Thirty-three (89%) accomplished the test according to the protocol and 1 moderate severe adverse event (bradycardia; heart rate 44) occurred shortly after the test. RF, Vo2, Vco2, and lactate increased significantly, whereas RER did not change during the active incremental exercise test. No changes were observed during the passive exercise test. ConclusionsIt is safe and feasible to perform exercise testing on a bed-based cycle ergometer in patients who are critically ill and a physiological response could be measured. Future research should investigate the clinical value of exercise testing in daily ICU practice and whether exercise capacity and its limiting factors could be determined by incremental exercise testing.

Effects of vagotomy on hypoglossal and phrenic responses to hypercapnia in the decerebrate rat

Hypercapnia characterizes a variety of physiological and pathological states and must be compensated effectively by the respiratory, cardiovascular, renal, and intra- and extracellular pH buffering systems to maintain homeostasis. Several studies have examined the respiratory response to hypercapnia, but contemporaneous changes in respiratory frequency and tidal volume prevent investigating the pure influence on respiratory amplitude. Therefore, we sought to test the effect of hypercapnia on hypoglossal (XII) and phrenic nerve (PN) inspiratory (Insp) and XII pre-inspiratory (pre-I) activities in vagus-intact and vagus-denervated animals. Experiments were performed on six artificially-ventilated unanesthetized pre-collicular decerebrate Sprague-Dawley adult male rats. Vagotomy under normocapnic conditions effected the consistent appearance of significant XII pre-I and a greater increase in XII than PN Insp amplitude. In the vagus-intact state, administration of a hypercapnic (5% CO2, 95% O2) gas mixture resulted in a greater increase in XII than PN Insp activity. In the vagotomized state, hypercapnia caused a drastic increase in XII pre-I and significant non-differential increases in both XII and PN Insp activity. The increase in XII pre-I was significantly greater than hypercapnia-induced increases in XII and PN Insp discharges. Following vagotomy, duration and amplitude of XII pre-I are potently modulated by CO2 tension. Based on our results, we conclude that vagal afferents exert differential inhibition of PN Insp and XII pre-I/Insp motor outputs. The role of vagal control in orchestration and optimization of respiratory response to hypercapnia is discussed.

Utility of a Novel Biofeedback Device for Within-Breath Modulation of Heart Rate in Rats: A Quantitative Comparison of Vagus Nerve vs. Right Atrial Pacing.

In an emerging bioelectronics era, there is a clinical need for physiological devices incorporating biofeedback that permits natural and demand-dependent control in real time. Here, we describe a novel device termed a central pattern generator (CPG) that uses cutting edge analog circuitry producing temporally controlled, electrical stimulus outputs based on the real time integration of physiological feedback. Motivated by the fact that respiratory sinus arrhythmia (RSA), which is the cyclical changes in heart rate every breath, is an essential component of heart rate variability (HRV) (an indicator of cardiac health), we have explored the versatility and efficiency of the CPG for producing respiratory modulation of heart rate in anesthetized, spontaneously breathing rats. Diaphragmatic electromyographic activity was used as the input to the device and its output connected to either the right cervical vagus nerve or the right atrium for pacing heart rate. We found that the CPG could induce respiratory related heart rate modulation that closely mimicked RSA. Whether connected to the vagus nerve or right atrium, the versatility of the device was demonstrated by permitting: (i) heart rate modulation in any phase of the respiratory cycle, (ii) control of the magnitude of heart rate modulation, and (iii) instant adaptation to changes in respiratory frequency. Vagal nerve pacing was only possible following transection of the nerve limiting its effective use chronically. Pacing via the right atrium permitted better flexibility and control of heart rate above its intrinsic level. This investigation now lays the foundation for future studies using this biofeedback technology permitting closer analysis of both the function and dysfunction of RSA.

Research on the respiratory frequency changes of 4DCT reconstructed image

Objective To study the impact of respiratory frequency and amplitude of patients with the thoracic or abdomen tumor on 4DCT's reconstructed image. Methods 75 thoracic or abdomen tumor patients who performed a scanning with belly belt-type respiratory gating on 4DCT between November 2012 to March 2013 in our hospital were retrieved. Reviewed their respiratory frequency, amplitude and fault distance of 4DCT's reconstructed image and analyzed the correlation fault distance of the reconstructed image. The correlation analysis was used by bivariate Spearman method. Results Among these reconstructed images, fault distance more than 6 mm could be seen in 11 cases, fault distance ranging from 3 mm to 6 mm could be found in 46 cases, and distance less than 3 mm could be detected in 18 case. Respiratory frequency correlated significantly with the amplitude (rs=0.369, P=0.000); the respiratory rate had a tight association with the fault distance of the reconstructed image (rs=0.273, P=0.018); and respiratory amplitude was associated obviously with the fault distance of the reconstructed image (rs=0.696, P=0.000). Conclusions Both 4DCT reconstructed image and respiratory amplitude are significantly correlated to the continuity of the respiratory frequency. The smaller the respiratory frequence and amplitude change are, the better continuity will be. Key words: Tomography, X-ray computed, four-dimensional; Respiratory frequency; Respiratory amplitudes; Reconstructed image

Disentangling the role of breathing in the cardiovascular response to meditation

Meditation practices are often associated with changes in respiratory pattern, which are known to independently affect cardiovascular responses. In this study we aim to isolate the specific effect of meditation on the cardiovascular system by systematically controlling for the role of respiration. Forty participants without prior meditation experience were tested while pacing breathing at predetermined rates, in the presence or absence of Mantra meditation instructions, and in a body-scan meditation that did not involved controlled breathing. Continuous recordings were acquired for respiratory excursion, electrocardiogram, skin vasomotion, arterial and brain oxygenation and blood pressure. Mantra meditation decreased heart rate and cerebral tissue oxygenation compared to baseline, significantly more than paced breathing (p 0.01). Moreover, meditation dampened the cardiorespiratory reactions to the concurrent control of breathing, preventing an increase in oxygen saturation and reducing the increase in chemoreflex sensitivity (p 0.05), tidal volume (p 0.01) and ventilation (p 0.05), compared to paced breathing. Body-scan meditation reproduced the pattern observed during Mantra meditation, despite the absence of change in respiratory frequency compared to baseline. Post-meditation resting recordings showed a persistence of slowed heart rate (p 0.001) and reduced respiratory rate (p 0.001) compared to initial baseline. Meditation induces a hypometabolic state that does not solely depend on respiratory changes, but is linked to the meditation practice per se.

Facilitation of the respiratory rhythm in mice by acute exposure to a progestin, the etonogestrel. Involvement of medullary areas

Background Works have underlined the facilitatory influence of progestins on central respiratory drive (CRD). The congenital central hypoventilation syndrome (CCHS) is a neuro-respiratory disease characterized by an alteration of the CO 2 /H + chemosensitivity due to dysfunction of CO 2 /H + chemosensitive/PHOX2b-positive neurons of the retrotrapezoid nucleus/parafacial respiratory group (RTN/pFRG). In our laboratory, a recovery of the CO 2 /H + chemosensitivity was fortuitously observed in two CCHS women who took a potent synthetic progestin, the desogestrel (Respir Physiol Neurobiol 2010;171:171–4). Objective Our aim was to appreciate the effects of an acute exposure to etonogestrel (ETO), the main active metabolite of the desogestrel, on the CRD and to determine its medullary action mechanisms. Methods We used: – an analysis of the effect of ETO (0.05–2 μM) on the CRD of ex vivo medullary-spinal cord preparations from newborn mice in both normopH and metabolic acidosis; – pharmacological co-application of ETO and muscimol or NMDA, agonists of GABA A or NMDA receptors known to be a target of some steroids; – an analysis of the c-fos expression in medullary respiratory structures. Results First, the respiratory frequency was: – dose-dependently increased in normopH by ETO (≈ +23–47%; P – increase by metabolic acidosis similarly under ETO (≈ +28–37% at 0.05–1 μM, P P P Second, changes in respiratory frequency induced by muscimol or NMDA at their EC 50 were more potent under ETO (≈ −60–63%, P P P P c-fos revealed ETO activated cells in respiratory medullary areas i.e. the ventrolateral medulla, nucleus of the solitary tract, RTN/pFRG and medullary raphe nuclei. Conclusions As a whole, data suggest that, by medullary mechanisms, the progestin ETO exerts a facilitatory influence on the CRD by acting at the level of respiratory structures. Involved mechanisms would implicate an interaction with GABA A and NMDA receptors. Besides, at least in newborn mice, ETO do not potentiate the respiratory response to metabolic acidosis by intrinsic medullary mechanisms.

Two separable mechanisms are responsible for mental stress effects on high frequency heart rate variability: An intra-individual approach in a healthy and a diabetic sample

Central withdrawal of parasympathetic cardiac control and increased respiratory frequency represent two important determinants of reduced respiratory-related heart rate variability (HRV). However, studies are missing to disentangle their relative contribution during mental stress. Healthy subjects (n=10) and type 2 diabetic patients (n=8), the latter with evidence of cardiac autonomic neuropathy, participated in this study. Using an intra-individual approach, high-frequency (hf) HRV was assessed for spontaneous (during rest and mental stress) and paced breathing (0.15, 0.2, 0.25, 0.3, 0.35, 0.4 and 0.45Hz; randomized sequence). Mental stress was induced by a challenging reaction time task. Effects of respiratory frequency on hf HRV were individually predicted by paced breathing data. Mental stress decreased hf HRV (p<.001), and increased respiratory frequency (p=.01). Individual prediction of hf HRV by stress respiratory frequency resulted in lower values (p=.02) than observed during rest, indicating that respiratory stress effects were sufficient to reduce hf HRV. However, observed hf HRV values during stress were even lower (p<.001). These results indicate that hf HRV reductions during stress can only partly be explained by concomitant respiratory frequency changes. This effect is detectable in healthy subjects and in patients with evidence of diabetic cardiac autonomic neuropathy.

Slow and deep respiration suppresses steady-state sympathetic nerve activity in patients with chronic heart failure: from modeling to clinical application.

Influences of slow and deep respiration on steady-state sympathetic nerve activity remain controversial in humans and could vary depending on disease conditions and basal sympathetic nerve activity. To elucidate the respiratory modulation of steady-state sympathetic nerve activity, we modeled the dynamic nature of the relationship between lung inflation and muscle sympathetic nerve activity (MSNA) in 11 heart failure patients with exaggerated sympathetic outflow at rest. An autoregressive exogenous input model was utilized to simulate entire responses of MSNA to variable respiratory patterns. In another 18 patients, we determined the influence of increasing tidal volume and slowing respiratory frequency on MSNA; 10 patients underwent a 15-min device-guided slow respiration and the remaining 8 had no respiratory modification. The model predicted that a 1-liter, step increase of lung volume decreased MSNA dynamically; its nadir (-33 ± 22%) occurred at 2.4 s; and steady-state decrease (-15 ± 5%), at 6 s. Actually, in patients with the device-guided slow and deep respiration, respiratory frequency effectively fell from 16.4 ± 3.9 to 6.7 ± 2.8/min (P < 0.0001) with a concomitant increase in tidal volume from 499 ± 206 to 1,177 ± 497 ml (P < 0.001). Consequently, steady-state MSNA was decreased by 31% (P < 0.005). In patients without respiratory modulation, there were no significant changes in respiratory frequency, tidal volume, and steady-state MSNA. Thus slow and deep respiration suppresses steady-state sympathetic nerve activity in patients with high levels of resting sympathetic tone as in heart failure.

Desobstrução ineficaz de vias aéreas: prevalência e espectro de seus indicadores clínicos

Objetivo: Identificar a prevalência do diagnóstico de enfermagem de desobstrução ineficaz de vias aéreas, indicadores clínicos e espectro de manifestação em crianças com infecção respiratória aguda; determinar associação entre os indicadores e a probabilidade de identificação. Métodos: Estudo transversal que incluiu 192 crianças internadas. Foram realizadas entrevistas e avaliação pulmonar, e os dados foram encaminhados a diagnosticadores para inferência diagnóstica. Utilizaram-se pacotes estatísticos para análise dos dados. Resultados: 71,9% das crianças apresentaram o diagnóstico em estudo. Os indicadores clínicos foram: tosse ineficaz, ruídos adventícios respiratórios, quantidade excessiva de muco, dispneia, ortopneia, mudança no ritmo respiratório e mudança na frequência respiratória; manifestados pelo espectro moderado. Os indicadores dispneia, inquietação, ortopneia, quantidade excessiva de muco, ruídos adventícios respiratórios e tosse ineficaz apresentaram relação linear significativa. Conclusão: O diagnóstico de enfermagem apresentou alta prevalência e associação entre os indicadores e a probabilidade de identificação do diagnóstico de enfermagem foi estabelecida.

Leptin into the ventrolateral medulla facilitates chemorespiratory response in leptin-deficient (ob/ob) mice.

Leptin, an adipocyte-derived hormone, is suggested to participate in the central control of breathing. We hypothesized that leptin may facilitate ventilatory responses to chemoreflex activation by acting on respiratory nuclei of the ventrolateral medulla. The baseline ventilation and the ventilatory responses to CO2 were evaluated before and after daily injections of leptin into the retrotrapezoid nucleus/parafacial respiratory group (RTN/pFRG) for 3 days in obese leptin-deficient (ob/ob) mice. Male ob/ob mice (40-45 g, n = 7 per group) received daily microinjections of vehicle or leptin (1 μg per 100 nL) for 3 days into the RTN/pFRG. Respiratory responses to CO2 were measured by whole-body plethysmography. Unilateral microinjection of leptin into the RTN/pFRG in ob/ob mice increased baseline ventilation (VE ) from 1447 ± 96 to 2405 ± 174 mL min(-1) kg(-1) by increasing tidal volume (VT ) from 6.4 ± 0.4 to 9.1 ± 0.8 mL kg(-1) (P < 0.05). Leptin also enhanced ventilatory responses to 7% CO2 (Δ = 2172 ± 218 mL min(-1) kg(-1) , vs. control: Δ = 1255 ± 105 mL min(-1) kg(-1) ), which was also due to increased VT (Δ = 4.71 ± 0.51 mL kg(-1) , vs. control: Δ = 2.27 ± 0.20 mL kg(-1) ), without changes in respiratory frequency. Leptin treatment into the RTN/pFRG or into the surrounding areas decreased food intake (83 and 70%, respectively), without significantly changing body weight. The present results suggest that leptin acting in the respiratory nuclei of the ventrolateral medulla improves baseline VE and VT and facilitates respiratory responses to hypercapnia in ob/ob mice.

Patient care services: What pharmacists do

Patient care services: What pharmacists do

APhA honors outstanding achievements at Annual Meeting

Each year, APhA recognizes exceptional contributors to the profession at the Annual Meeting. The following award winners will be honored at APhA2014 in Orlando.

Chemosensory control by purinergic signaling within the retrotrapezoid nucleus (RTN) in conscious rats

The RTN contains a population of CO2/H+‐sensitive neurons that send excitatory projections to respiratory centers to regulate breathing (i.e., chemoreceptors). Evidence also suggests that ATP, possibly released by astrocytes, is an important mediator of RTN chemoreceptor activity. However, this possibility has yet to be tested in conscious animals. The goal of this study is to determine if purinergic signaling in the RTN contributes to breathing under resting conditions and during central chemoreflex activation in unrestrained awake rats. Male Wistar rats (280–300 g) with bilateral stainless steel cannulas implanted into the RTN were used. Bilateral RTN injections of PPADS (P2‐receptor antagonist: 5 mM ‐ 50 nl) did not change baseline minute ventilation (VE), mean arterial pressure (MAP), or heart rate (HR). However, PPADS treated animals exhibited reduced tidal volume (VT) (6.6 ± 0.14 vs. saline: 9.1 ± 1.4 ml/kg) and VE (748 ± 2.5 vs. saline: 1257 ± 239 ml/kg/min) responses to hypercapnia (7% CO2). CO2‐induced changes in respiratory frequency, MAP and HR were not affected by PPADS. These results suggest that CO2‐evoked ATP release in the RTN contributes to control of breathing in conscious animals

Acute inhibition of glial cells in the NTS does not affect respiratory and sympathetic activities in rats exposed to chronic intermittent hypoxia

Recent studies suggest that neuron–glia interactions are involved in multiple aspects of neuronal activity regulation. In the nucleus tractus solitarius (NTS) neuron–glia interactions are thought to participate in the integration of autonomic responses to physiological challenges. However, it remains to be shown whether NTS glial cells might influence breathing and cardiovascular control, and also if they could be integral to the autonomic and respiratory responses to hypoxic challenges. Here, we investigated whether NTS glia play a tonic role in the modulation of central respiratory and sympathetic activities as well as in the changes in respiratory–sympathetic coupling induced by exposure to chronic intermittent hypoxia (CIH), a model of central autonomic and respiratory plasticity. We show that bilateral microinjections of fluorocitrate (FCt), a glial cell inhibitor, into the caudal and intermediate subnuclei of the NTS did not alter baseline respiratory and sympathetic parameters in in situ preparations of juvenile rats. Similar results were observed in rats previously exposed to CIH. Likewise, CIH-induced changes in respiratory–sympathetic coupling were unaffected by FCt-mediated inhibition. However, microinjection of FCt into the ventral medulla produced changes in respiratory frequency. Our results show that acute glial inhibition in the NTS does not affect baseline respiratory and sympathetic control. Additionally, we conclude that NTS glial cells may not be necessary for the continuous manifestation of sympathetic and respiratory adaptations to CIH. Our work provides evidence that neuron–glia interactions in the NTS do not participate in baseline respiratory and sympathetic control.