Role of deflation-sensitive feedback in control of end-expiratory volume in rats

1993 ◽  
Vol 75 (2) ◽  
pp. 902-911 ◽  
Author(s):  
M. Sammon ◽  
J. R. Romaniuk ◽  
E. N. Bruce
Keyword(s):  
Respiratory Pattern ◽  
Electromyographic Activity ◽  
Phase Switching ◽  
Inspiratory Muscles ◽  
Tracheal Pressure ◽  
Posterior Cricoarytenoid ◽  
Lung Deflation ◽  
Nerve Recordings ◽  
Thyroarytenoid Muscle

Rats breathing from reduced end-expiratory volumes (EEV) exhibit transient bursting of inspiratory airflow local to the expiratory-inspiratory transition (E-I) accompanied by increases in inspiration-to-expiration duration ratio. Continuous positive (CPAP) and negative (CNAP) airway pressures (+3 to -9 cmH2O) were applied to tracheal openings of 17 unilaterally vagotomized rats (urethan anesthetized) to evaluate the feedback mechanisms associated with these oscillatory "expiratory interrupts." Whole nerve recordings of afferent vagus (Vag) were primarily inspiratory with CPAP. As tracheal pressure was reduced in a stepwise manner, progressive decreases in inspiratory peaks and increases in activity during late expiration were seen on Vag. Single-fiber recordings correlate Vag expiratory activity with slowly adapting receptors sensitive to lung deflation. With CNAP, 1) progressively earlier onsets of activity in inspiratory muscles (e.g., diaphragm, genioglossus, posterior cricoarytenoid) were observed (increased inspiratory duration, decreased expiratory duration); oscillations at E-I developed only when expiratory peaks on Vag were significant. 2) Thyroarytenoid muscle exhibited onset of electromyographic activity that immediately succeeded onset of Vag during late expiration. When the trachea is intact, these two actions might combine to produce a respiratory pattern similar to the "grunting" often seen in newborns breathing from reduced EEVs. In contrast to larger mammals, rats rely strongly on deflation reflexes for control of E-I phase switching, presumably to aid in maintenance of an elevated EEV.

Bifurcations of the respiratory pattern associated with reduced lung volume in the rat

1993 ◽  
Vol 75 (2) ◽  
pp. 887-901 ◽  
Author(s):  
M. Sammon ◽  
J. R. Romaniuk ◽  
E. N. Bruce
Keyword(s):  
Degrees Of Freedom ◽  
Power Spectra ◽  
Phase Portraits ◽  
Respiratory Pattern ◽  
Phase Switching ◽  
Correlation Integral ◽  
Switching Dynamics ◽  
Tracheal Pressure ◽  
Lung Deflation ◽  
Low Dimensional

Rats with intact vagal reflexes exhibit patterns of breathing that contain greater degrees of freedom than those seen after vagotomy. To determine how alterations in end-expiratory volume modify the respiratory pattern, continuous positive (CPAP) and negative (CNAP) airway pressure was applied to tracheal openings of nine urethan-anesthetized vagi-intact rats (+3 to -9 cmH2O). Phase portraits (e.g., volume vs. flow curves), power spectra, correlation integral curves, and inspiratory-to-expiratory duration (TI/TE) ratios are used to interpret the vagal-dependent responses to changes in mean tracheal pressure (Ptr). With CPAP, respiratory oscillation was highly periodic and one dimensional, with TI/TE near 1.0. As Ptr was reduced in a stepwise manner, transient bursts of inspiratory airflow developed local to the expiratory-inspiratory transition, with amplitude increasing proportionally with the level of CNAP. These oscillatory "expiratory interrupts" (doubling TI/TE in five of nine cases) produced highly variable and asymmetric respiratory patterns. Progressive increases in correlation dimension (maximum = 1.8–3.0) and tendencies toward broadband power spectra were seen as Ptr was lowered. The irregular phase-switching dynamics seen with CNAP (which disappeared after vagotomy) are consistent with onset of low-dimensional chaos, probably correlated with activation of feedback mechanisms responsive to lung deflation.

Timing of Glottic Closure during Swallowing: A Combined Electromyographic and Endoscopic Analysis

2005 ◽  
Vol 114 (6) ◽  
pp. 478-487 ◽  
Author(s):  
Douglas J. Van Daele ◽  
Timothy M. McCulloch ◽  
Phyllis M. Palmer ◽  
Susan E. Langmore
Keyword(s):  
Human Subjects ◽  
Case Series ◽  
Video Frame ◽  
Electromyographic Activity ◽  
Healthy Human ◽  
Glottic Closure ◽  
Posterior Cricoarytenoid Muscle ◽  
Multiple Trials ◽  
Posterior Cricoarytenoid ◽  
Thyroarytenoid Muscle

Objectives: We performed a case series to enhance our understanding of the coupling between neuromuscular events and glottic closure. Methods: We performed combined flexible video laryngoscopy and electromyography in 4 healthy human subjects. Hooked-wire electrodes were placed in the superior pharyngeal constrictor, longitudinal pharyngeal, cricopharyngeus, thyroarytenoid, genioglossus, suprahyoid, and posterior cricoarytenoid muscles. A flexible endoscope tip was positioned in the oropharyngeal-hypopharyngeal region. The subjects performed multiple trials each of 10-mL normal and super-supraglottic liquid swallows. Results: Arytenoid movement consistently preceded full glottic closure and was associated with cessation of activity of the posterior cricoarytenoid muscle. In 89% of normal swallows, the glottis was partially open in the video frame before bolus passage. The maximum amount of thyroarytenoid electromyographic activity occurred during endoscopic white-out. When subjects executed a super-supraglottic swallow, early thyroarytenoid activity coincided with arytenoid contact. Conclusions: The initial medialization of the arytenoids is due to a decrease in motor tone of the posterior cricoarytenoid muscle. Full glottic closure typically occurs late in the process of swallowing, with activation of the thyroarytenoid muscle. Shifting of arytenoid medialization and glottic closure earlier in the super-supraglottic swallow indicates that glottic closure is under significant voluntary control.

Thyroarytenoid muscle activity during loaded and nonloaded breathing in adult humans

1991 ◽  
Vol 70 (6) ◽  
pp. 2410-2416 ◽  
Author(s):  
G. Insalaco ◽  
S. T. Kuna ◽  
B. M. Costanza ◽  
G. Catania ◽  
F. Cibella ◽  
...  
Keyword(s):  
Respiratory Pattern ◽  
Electromyographic Activity ◽  
Quiet Breathing ◽  
Adult Humans ◽  
Loaded Breathing ◽  
Inspiratory Activity ◽  
Loaded State ◽  
Resistive Loads ◽  
Active Phenomenon ◽  
Thyroarytenoid Muscle

Previous fiber-optic studies in humans have demonstrated narrowing of the glottic aperture in expiration during application of expiratory resistive loads. Nine healthy subjects were studied to determine the effect of expiratory resistive loads on the electromyographic activity of the thyroarytenoid (TA) muscle, a vocal cord adductor. Four of the nine subjects also underwent the application of inspiratory resistive loads and voluntary prolongation of either inspiratory (TI) or expiratory (TE) time. TA activity was recorded by intramuscular hooked-wire electrodes. During quiet breathing in all subjects, the TA was phasically active on expiration and often tonically active throughout the respiratory cycle. TA expiratory activity progressively increased with increasing levels of expiratory load. Inspiratory loads resulted in increased TA "inspiratory" activity. Voluntary prolongation of TE to times similar to those reached during loaded breathing induced increases in TA expiratory activity similar to those reached during the loaded state. Voluntary prolongation of TI was associated with an increase in TA inspiratory activity. Similar increases in TI during inspiratory loading or voluntary conditions were associated with comparable increases in TA inspiratory activity in three of the four subjects. In conclusion, increased activation of TA during the application of expiratory resistive loads implies that the reported narrowing of glottic aperture during expiratory loading is an active phenomenon. Changes in activation of the TA with resistive loads appear to be related to changes in respiratory pattern.

scholarly journals The role of spinal GABAergic circuits in the control of phrenic nerve motor output

2015 ◽  
Vol 308 (11) ◽  
pp. R916-R926 ◽  
Author(s):  
Vitaliy Marchenko ◽  
Michael G. Z. Ghali ◽  
Robert F. Rogers
Keyword(s):  
Phrenic Nerve ◽  
Physiological Role ◽  
Ventral Horn ◽  
Motor Output ◽  
Respiratory Pattern ◽  
Adult Rats ◽  
Spinal Circuitry ◽  
Phrenic Nucleus ◽  
Nerve Recordings

While supraspinal mechanisms underlying respiratory pattern formation are well characterized, the contribution of spinal circuitry to the same remains poorly understood. In this study, we tested the hypothesis that intraspinal GABAergic circuits are involved in shaping phrenic motor output. To this end, we performed bilateral phrenic nerve recordings in anesthetized adult rats and observed neurogram changes in response to knocking down expression of both isoforms (65 and 67 kDa) of glutamate decarboxylase (GAD65/67) using microinjections of anti-GAD65/67 short-interference RNA (siRNA) in the phrenic nucleus. The number of GAD65/67-positive cells was drastically reduced on the side of siRNA microinjections, especially in the lateral aspects of Rexed's laminae VII and IX in the ventral horn of cervical segment C4, but not contralateral to microinjections. We hypothesize that intraspinal GABAergic control of phrenic output is primarily phasic, but also plays an important role in tonic regulation of phrenic discharge. Also, we identified respiration-modulated GABAergic interneurons (both inspiratory and expiratory) located slightly dorsal to the phrenic nucleus. Our data provide the first direct evidence for the existence of intraspinal GABAergic circuits contributing to the formation of phrenic output. The physiological role of local intraspinal inhibition, independent of descending direct bulbospinal control, is discussed.

Effects of hypercapnia on inspiratory and expiratory muscle activity during expiration

1985 ◽  
Vol 59 (5) ◽  
pp. 1560-1565 ◽  
Author(s):  
A. Oliven ◽  
E. C. Deal ◽  
S. G. Kelsen ◽  
N. S. Cherniack
Keyword(s):  
Muscle Activity ◽  
Opposite Effect ◽  
Afferent Activity ◽  
Expiratory Muscle ◽  
Inspiratory Muscles ◽  
Before And After ◽  
Expiratory Muscles ◽  
External Oblique ◽  
Lung Deflation

Persistence of inspiratory muscle activity during the early phase of expiratory airflow slows the rate of lung deflation, whereas heightened expiratory muscle activity produces the opposite effect. To examine the influence of increased chemoreceptor drive and the role of vagal afferent activity on these processes, the effects of progressive hypercapnia were evaluated in 12 anesthetized tracheotomized dogs before and after vagotomy. Postinspiratory activity of inspiratory muscles (PIIA) and the activity of expiratory muscles were studied. During resting breathing, the duration of PIIA correlated with the duration of inspiration but not with expiration. Parasternal intercostal PIIA was directly related to that of the diaphragm. Based on their PIIA, dogs could be divided into two groups: one with prolonged PIIA (mean 0.57 s) and the other with brief PIIA (mean 0.16 s). Hypercapnia caused progressive shortening of the PIIA in the dogs with prolonged PIIA during resting breathing. The electrical activity of the external oblique and internal intercostal muscles increased gradually during CO2 rebreathing in all dogs both pre- and postvagotomy. After vagotomy, abdominal activity continued to increase with hypercapnia but was less at all levels of PCO2. The internal intercostal response to hypercapnia was not affected by vagotomy. The combination of shorter PIIA and augmented expiratory activity with hypercapnia might, in addition to changes in lung recoil pressure and airway resistance, hasten exhalation.

scholarly journals Changes in electromyographic activity, mechanical power, and relaxation rates following inspiratory ribcage muscle fatigue

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Antonio Sarmento ◽  
Guilherme Fregonezi ◽  
Maria Lira ◽  
Layana Marques ◽  
Francesca Pennati ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Low Frequency ◽  
Mechanical Power ◽  
Electromyographic Activity ◽  
Median Frequency ◽  
Relaxation Rates ◽  
Shortening Velocity ◽  
Inspiratory Muscles ◽  
Underlying Mechanisms

AbstractMuscle fatigue is a complex phenomenon enclosing various mechanisms. Despite technological advances, these mechanisms are still not fully understood in vivo. Here, simultaneous measurements of pressure, volume, and ribcage inspiratory muscle activity were performed non-invasively during fatigue (inspiratory threshold valve set at 70% of maximal inspiratory pressure) and recovery to verify if inspiratory ribcage muscle fatigue (1) leads to slowing of contraction and relaxation properties of ribcage muscles and (2) alters median frequency and high-to-low frequency ratio (H/L). During the fatigue protocol, sternocleidomastoid showed the fastest decrease in median frequency and slowest decrease in H/L. Fatigue was also characterized by a reduction in the relative power of the high-frequency and increase of the low-frequency. During recovery, changes in mechanical power were due to changes in shortening velocity with long-lasting reduction in pressure generation, and slowing of relaxation [i.e., tau (τ), half-relaxation time (½RT), and maximum relaxation rate (MRR)] was observed with no significant changes in contractile properties. Recovery of median frequency was faster than H/L, and relaxation rates correlated with shortening velocity and mechanical power of inspiratory ribcage muscles; however, with different time courses. Time constant of the inspiratory ribcage muscles during fatigue and recovery is not uniform (i.e., different inspiratory muscles may have different underlying mechanisms of fatigue), and MRR, ½RT, and τ are not only useful predictors of inspiratory ribcage muscle recovery but may also share common underlying mechanisms with shortening velocity.

scholarly journals Enhancement of Methacholine-Evoked Tracheal Contraction Induced by Bacterial Lipopolysaccharides Depends on Epithelium and Tumor Necrosis Factor

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
T. Secher ◽  
F. Rodrigues Coelho ◽  
N. Noulin ◽  
A. Lino dos Santos Franco ◽  
V. Quesniaux ◽  
...  
Keyword(s):  
Contractile Response ◽  
Ex Vivo ◽  
Adaptor Protein ◽  
Respiratory Pattern ◽  
Necrosis Factor Alpha ◽  
Factor Alpha ◽  
Bacterial Lipopolysaccharides ◽  
Necrosis Factor

Inhaled bacterial lipopolysaccharides (LPSs) induce an acute tumour necrosis factor-alpha (TNF-α-) dependent inflammatory response in the murine airways mediated by Toll-like receptor 4 (TLR4) via the myeloid differentiation MyD88 adaptor protein pathway. However, the contractile response of the bronchial smooth muscle and the role of endogenous TNFα in this process have been elusive. We determined the in vivo respiratory pattern of C57BL/6 mice after intranasal LPS administration with or without the presence of increasing doses of methacholine (MCh). We found that LPS administration altered the basal and MCh-evoked respiratory pattern that peaked at 90 min and decreased thereafter in the next 48 h, reaching basal levels 7 days later. We investigated in controlled ex vivo condition the isometric contraction of isolated tracheal rings in response to MCh cholinergic stimulation. We observed that preincubation of the tracheal rings with LPS for 90 min enhanced the subsequent MCh-induced contractile response (hyperreactivity), which was prevented by prior neutralization of TNFα with a specific antibody. Furthermore, hyperreactivity induced by LPS depended on an intact epithelium, whereas hyperreactivity induced by TNFα was well maintained in the absence of epithelium. Finally, the enhanced contractile response to MCh induced by LPS when compared with control mice was not observed in tracheal rings from TLR4- or TNF- or TNF-receptor-deficient mice. We conclude that bacterial endotoxin-mediated hyperreactivity of isolated tracheal rings to MCh depends upon TLR4 integrity that signals the activation of epithelium, which release endogenous TNFα.

Studies on the role of the lung deflation reflex

1970 ◽  
Vol 10 (2) ◽  
pp. 172-183 ◽  
Author(s):  
E.A. Koller ◽  
P. Ferrer
Keyword(s):  
Lung Deflation

scholarly journals Reconfiguration of the Pontomedullary Respiratory Network: A Computational Modeling Study With Coordinated In Vivo Experiments

2008 ◽  
Vol 100 (4) ◽  
pp. 1770-1799 ◽  
Author(s):  
I. A. Rybak ◽  
R. O'Connor ◽  
A. Ross ◽  
N. A. Shevtsova ◽  
S. C. Nuding ◽  
...  
Keyword(s):  
Computational Models ◽  
Ad Hoc ◽  
Large Body ◽  
Network Activity ◽  
Respiratory Pattern ◽  
Respiratory Neurons ◽  
Phase Switching ◽  
In Vivo Experiments ◽  
Respiratory Network

A large body of data suggests that the pontine respiratory group (PRG) is involved in respiratory phase-switching and the reconfiguration of the brain stem respiratory network. However, connectivity between the PRG and ventral respiratory column (VRC) in computational models has been largely ad hoc. We developed a network model with PRG-VRC connectivity inferred from coordinated in vivo experiments. Neurons were modeled in the “integrate-and-fire” style; some neurons had pacemaker properties derived from the model of Breen et al. We recapitulated earlier modeling results, including reproduction of activity profiles of different respiratory neurons and motor outputs, and their changes under different conditions (vagotomy, pontine lesions, etc.). The model also reproduced characteristic changes in neuronal and motor patterns observed in vivo during fictive cough and during hypoxia in non-rapid eye movement sleep. Our simulations suggested possible mechanisms for respiratory pattern reorganization during these behaviors. The model predicted that network- and pacemaker-generated rhythms could be co-expressed during the transition from gasping to eupnea, producing a combined “burst-ramp” pattern of phrenic discharges. To test this prediction, phrenic activity and multiple single neuron spike trains were monitored in vagotomized, decerebrate, immobilized, thoracotomized, and artificially ventilated cats during hypoxia and recovery. In most experiments, phrenic discharge patterns during recovery from hypoxia were similar to those predicted by the model. We conclude that under certain conditions, e.g., during recovery from severe brain hypoxia, components of a distributed network activity present during eupnea can be co-expressed with gasp patterns generated by a distinct, functionally “simplified” mechanism.

Reinnervation of the Canine Posterior Cricoarytenoid Muscle with Sympathetic Preganglionic Neurons

1990 ◽  
Vol 99 (3) ◽  
pp. 167-174 ◽  
Author(s):  
Ian N. Jacobs ◽  
Bei-Lian Wu ◽  
Ira Sanders ◽  
Hugh F. Biller
Keyword(s):  
Vocal Cord Paralysis ◽  
Fiber Type ◽  
Electromyographic Activity ◽  
Glycogen Depletion ◽  
Bilateral Vocal Cord Paralysis ◽  
Preganglionic Neurons ◽  
Posterior Cricoarytenoid Muscle ◽  
Posterior Cricoarytenoid ◽  
The Right ◽  
Stimulation Of

This experiment investigated the reinnervation of the canine posterior cricoarytenoid (PCA) muscle with preganglionic neurons of the sympathetic nervous system. Six dogs had their right recurrent laryngeal nerve (RLN) sectioned. Four of these dogs had the sympathetic cervical trunk (SCT) implanted into the right PCA muscle, and the two remaining dogs served as denervated controls. Four months later all dogs underwent videolaryngoscopy, electromyography, and electrical stimulation of the SCT. The PCA muscles were excised, sectioned, and stained for glycogen and ATPase. All four experimental PCA muscles demonstrated electrically evoked abduction and tonic electromyographic activity. In two of the specimens, staining (ATPase and PAS) revealed areas of reinnervation with fiber type grouping and glycogen depletion. These results are consistent with the successful reinnervation of the PCA muscle. Further refinement of this technique could be of benefit to patients with bilateral vocal cord paralysis.

Sign in / Sign up

Export Citation Format

Share Document