Expiratory abdominal muscle activity during ventilatory chemostimulation in piglets

1990 ◽  
Vol 68 (4) ◽  
pp. 1343-1349 ◽  
Author(s):  
J. F. Watchko ◽  
T. L. O'Day ◽  
B. S. Brozanski ◽  
R. D. Guthrie
Keyword(s):  
Abdominal Muscle ◽  
Vagal Afferents ◽  
Emg Activity ◽  
Abdominal Muscles ◽  
Base Line ◽  
Afferent Pathways ◽  
Newborn Piglets ◽  
Before And After ◽  
Cervical Vagotomy ◽  
Time Average

We examined abdominal muscle minute electromyographic (EMG) activity (peak moving time average EMG x respiratory rate) during eupnea, hyperoxic hypercapnia (8% CO2-40% O2-balance N2), and hypoxia (13% O2) in 12 anesthetized (0.5% halothane) newborn piglets. In addition, we assessed the role of vagal afferent pathways in the abdominal muscles' response to ventilatory chemostimulation by examining abdominal EMG activity (EMGab) before and after bilateral cervical vagotomy in five animals. Phasic expiratory EMGab was observed in 11 of 12 piglets during eupnea. Hypercapnia was associated with a sustained augmentation of minute EMGab (444 +/- 208% control). In contrast, hypoxia consistently augmented (1 min, 193 +/- 33% control) then diminished (5 min, 126 +/- 39% control) minute EMGab. Vagotomy resulted in a decline in peak moving time average EMGab by approximately one-half (48 +/- 18% control); the abdominal muscles' response to ventilatory chemostimulation, however, was qualitatively unchanged. We conclude that 1) expiration during eupnea in anesthetized newborn piglets is associated with phasic EMGab; 2) both hypercapnia and hypoxia augment minute EMGab; however, only hypercapnia is associated with sustained augmentation; and 3) although vagal afferents have a role in modulating the base-line level of EMGab, other extravagal mechanisms appear to determine the pattern of EMGab in response to ventilatory chemostimulation.

Expiratory motor responses in the suckling opossum

1983 ◽  
Vol 54 (4) ◽  
pp. 919-925 ◽  
Author(s):  
J. P. Farber
Keyword(s):  
Muscle Activity ◽  
Abdominal Muscle ◽  
Vagal Afferents ◽  
Emg Activity ◽  
Abdominal Muscles ◽  
Motor Responses ◽  
Series Of Experiments ◽  
Unanesthetized Animals ◽  
Muscle Responses ◽  
Slow Onset

To evaluate developmental aspects of expiratory muscle utilization, ventilation and electromyographic (EMG) activity from abdominal muscles were measured in unanesthetized suckling opossums. From about 20–35 days of age, breathing against a continuous positive airway pressure (CPAP) or inhalation of hypercapnic and asphyxiant test gases (ventilatory chemostimulation) increased or initiated a sustained expiratory-phased abdominal EMG discharge. Using younger animals, such responses could not be demonstrated during test manipulations, or pattern of activation was not typical of that observed in the older group. In another series of experiments, vagal mechanisms underlying expiratory abdominal muscle responses were evaluated by using lightly anesthetized animals. Unilateral vagotomy reduced abdominal EMG levels during ventilatory chemostimulation while minimally affecting breathing pattern; in addition, abdominal muscle activity during CPAP was of slower onset than before vagotomy. Slow onset of abdominal muscle activity was also seen in relatively young intact unanesthetized animals during responses to CPAP. Thus vagal afferents mediate expiratory motor responses during chemostimulation of breathing and may account, in part, for maturation of expiratory responses to CPAP.

Effects of postural changes and vestibular lesions on diaphragm and rectus abdominis activity in awake cats

2001 ◽  
Vol 91 (1) ◽  
pp. 137-144 ◽  
Author(s):  
L. A. Cotter ◽  
H. E. Arendt ◽  
J. G. Jasko ◽  
C. Sprando ◽  
S. P. Cass ◽  
...  
Keyword(s):  
Vestibular System ◽  
Muscle Activity ◽  
Abdominal Muscle ◽  
Rectus Abdominis ◽  
Abdominal Muscles ◽  
Body Rotation ◽  
Postural Changes ◽  
Before And After ◽  
Awake Cats

Changes in posture can affect the resting length of the diaphragm, requiring alterations in the activity of both the abdominal muscles and the diaphragm to maintain stable ventilation. To determine the role of the vestibular system in regulating respiratory muscle discharges during postural changes, spontaneous diaphragm and rectus abdominis activity and modulation of the firing of these muscles during nose-up and ear-down tilt were compared before and after removal of labyrinthine inputs in awake cats. In vestibular-intact animals, nose-up and ear-down tilts from the prone position altered rectus abdominis firing, whereas the effects of body rotation on diaphragm activity were not statistically significant. After peripheral vestibular lesions, spontaneous diaphragm and rectus abdominis discharges increased significantly (by ∼170%), and augmentation of rectus abdominis activity during nose-up body rotation was diminished. However, spontaneous muscle activity and responses to tilt began to recover after a few days after the lesions, presumably because of plasticity in the central vestibular system. These data suggest that the vestibular system provides tonic inhibitory influences on rectus abdominis and the diaphragm and in addition contributes to eliciting increases in abdominal muscle activity during some changes in body orientation.

Cardiopulmonary reflexes and blood pressure in exercising sinoaortic-denervated dogs

1984 ◽  
Vol 57 (5) ◽  
pp. 1417-1421 ◽  
Author(s):  
D. A. Daskalopoulos ◽  
J. T. Shepherd ◽  
S. C. Walgenbach
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Vagal Afferents ◽  
Systemic Resistance ◽  
Vigorous Exercise ◽  
Arterial Blood ◽  
Resistance Vessels ◽  
Before And After ◽  
Cervical Vagotomy ◽  
Cardiopulmonary Receptors

To examine the role of cardiopulmonary receptors in arterial blood pressure regulation during and after exercise, conscious dogs with chronic sinoaortic denervation were subjected to 12 min of light exercise and 12 min of exercise that increased in severity every 3 min. Hemodynamic measurements were made before and after interruption of cardiopulmonary afferents by bilateral cervical vagotomy. During both exercise protocols, after an initial transient decrease, the arterial blood pressure remained close to resting values before and after vagotomy. On cessation of the graded exercise, the arterial blood pressure did not change before, but a rapid and sustained increase in pressure occurred after vagotomy. At the time of this increase the cardiac output and heart rate were returning rapidly to the resting level. The study demonstrates that in the chronic absence of arterial baroreflexes, vagal afferents prevent a rise in arterial blood pressure after vigorous exercise presumably by the action of cardiopulmonary receptors causing a rapid dilatation of systemic resistance vessels.

scholarly journals Recruitment and plasticity in diaphragm, intercostal, and abdominal muscles in unanesthetized rats

2014 ◽  
Vol 117 (2) ◽  
pp. 180-188 ◽  
Author(s):  
A. Navarrete-Opazo ◽  
G. S. Mitchell
Keyword(s):  
Respiratory Muscles ◽  
Abdominal Muscle ◽  
Emg Activity ◽  
Abdominal Muscles ◽  
Emg Amplitude ◽  
Inspiratory Activity ◽  
Unanesthetized Animals ◽  
Long Term Facilitation ◽  
Relative Capacity

Although rats are a frequent model for studies of plasticity in respiratory motor control, the relative capacity of rat accessory respiratory muscles to express plasticity is not well known, particularly in unanesthetized animals. Here, we characterized external intercostal (T2, T4, T5, T6, T7, T8, T9 EIC) and abdominal muscle (external oblique and rectus abdominis) electromyogram (EMG) activity in unanesthetized rats via radiotelemetry during normoxia (Nx: 21% O2) and following acute intermittent hypoxia (AIH: 10 × 5-min, 10.5% O2; 5-min intervals). Diaphragm and T2–T5 EIC EMG activity, and ventilation were also assessed during maximal chemoreceptor stimulation (MCS: 7% CO2, 10.5% O2) and sustained hypoxia (SH: 10.5% O2). In Nx, T2 EIC exhibits prominent inspiratory activity, whereas T4, T5, T6, and T7 EIC inspiratory activity decreases in a caudal direction. T8 and T9 EIC and abdominal muscles show only tonic or sporadic activity, without consistent respiratory activity. MCS increases diaphragm and T2 EIC EMG amplitude and tidal volume more than SH (0.94 ± 0.10 vs. 0.68 ± 0.05 ml/100 g; P < 0.001). Following AIH, T2 EIC EMG amplitude remained above baseline for more than 60 min post-AIH (i.e., EIC long-term facilitation, LTF), and was greater than diaphragm LTF (41.5 ± 1.3% vs. 19.1 ± 2.0% baseline; P < 0.001). We conclude that 1) diaphragm and rostral T2–T5 EIC muscles exhibit inspiratory activity during Nx; 2) MCS elicits greater ventilatory, diaphragm, and rostral T2–T5 EIC muscle activity vs. SH; and 3) AIH induces greater rostral EIC LTF than diaphragm LTF.

Electromyographic Evaluation of Abdominal-Muscle Function With and Without Concomitant Pelvic-Floor-Muscle Contraction

2013 ◽  
Vol 22 (2) ◽  
pp. 108-114 ◽  
Author(s):  
Nahid Tahan ◽  
Amir Massoud Arab ◽  
Bita Vaseghi ◽  
Khosro Khademi
Keyword(s):  
Pelvic Floor ◽  
Muscle Contraction ◽  
Outcome Measures ◽  
Repeated Measures ◽  
Pelvic Floor Muscle ◽  
Abdominal Muscle ◽  
Emg Activity ◽  
Abdominal Muscles ◽  
Repeated Measures Design ◽  
Emg Signal

Context:Coactivation of abdominal and pelvic-floor muscles (PFM) is an issue considered by researchers recently. Electromyography (EMG) studies have shown that the abdominal-muscle activity is a normal response to PFM activity, and increase in EMG activity of the PFM concomitant with abdominal-muscle contraction was also reported.Objective:The purpose of this study was to compare the changes in EMG activity of the deep abdominal muscles during abdominal-muscle contraction (abdominal hollowing and bracing) with and without concomitant PFM contraction in healthy and low-back-pain (LBP) subjects.Design:A 2 × 2 repeated-measures design.Setting:Laboratory.Participants:30 subjects (15 with LBP, 15 without LBP).Main Outcome Measures:Peak rectified EMG of abdominal muscles.Results:No difference in EMG of abdominal muscles with and without concomitant PFM contraction in abdominal hollowing (P = .84) and abdominal bracing (P = .53). No difference in EMG signal of abdominal muscles with and without PFM contraction between LBP and healthy subjects in both abdominal hollowing (P = .88) and abdominal bracing (P = .98) maneuvers.Conclusion:Adding PFM contraction had no significant effect on abdominal-muscle contraction in subjects with and without LBP.

Control of abdominal and expiratory intercostal muscle activity during vomiting: role of ventral respiratory group expiratory neurons

1987 ◽  
Vol 57 (6) ◽  
pp. 1854-1866 ◽  
Author(s):  
A. D. Miller ◽  
L. K. Tan ◽  
I. Suzuki
Keyword(s):  
Muscle Activity ◽  
Discharge Rate ◽  
Abdominal Muscle ◽  
Lumbar Spinal Cord ◽  
Abdominal Muscles ◽  
Ventral Respiratory Group ◽  
Before And After ◽  
The One ◽  
Lumbar Spinal

The role of ventral respiratory group (VRG) expiratory (E) neurons in the control of abdominal and internal intercostal (expiratory) muscle activity during vomiting was examined in decerebrate cats by recording from these neurons during fictive vomiting in paralyzed animals and comparing abdominal muscle activity during vomiting before and after sectioning the axons of these descending neurons. Fictive vomiting was defined by a series of bursts of coactivation of abdominal and phrenic nerves elicited by either subdiaphragmatic vagus nerve stimulation or emetic drugs. Such coordinated activity would be expected to produce vomiting if the animals were not paralyzed. Data were recorded from 27 VRG E neurons that were antidromically activated from the lower thoracic (T13) or lumbar spinal cord. During fictive vomiting, almost two-thirds of these neurons (17/27) were mainly active in between periods of abdominal and phrenic nerve coactivation, when the internal intercostal motoneurons are known to be active. This group of neurons was termed INT neurons. INT neurons were subdivided according to whether they were active between every burst of phrenic and abdominal nerve coactivation (INTa neurons, n = 10) or only between some bursts (INTb neurons, n = 7). Another one-third of the VRG E neurons had normal or increased levels of activity when the abdominal nerves were active during fictive vomiting (ABD neurons). The one remaining neuron was mainly silent throughout fictive vomiting. ABD neurons were indistinguishable from INT neurons on the basis of their location in the VRG, type of firing pattern (ramp versus step ramp), conduction velocity, or extent of projection in the lumbar cord. However, INTa neurons had a significantly higher discharge rate during respiration than either ABD or INTb neurons. Abdominal muscle EMG and nerve activity were recorded from six unparalyzed cats before and after cutting the axons of VRG E neurons as they cross the midline between C1 and the obex. The lesions abolished or almost eliminated expiratory modulation of abdominal muscle activity. In contrast, the abdominal muscles were always active during vomiting; however, the amplitude of postlesion abdominal activity varied from approximately 70-100% of prelesion values in three cats to 60-70% of normal in a fourth animal to only approximately 20% of prelesion values in two other cats.(ABSTRACT TRUNCATED AT 400 WORDS)

Response of collateral channels to histamine: lack of vagal effect

1981 ◽  
Vol 51 (5) ◽  
pp. 1314-1319 ◽  
Author(s):  
J. Kaplan ◽  
G. C. Smaldone ◽  
H. A. Menkes ◽  
D. L. Swift ◽  
R. J. Traystman
Keyword(s):  
Base Line ◽  
Flexible Fiber ◽  
Before And After ◽  
Cervical Vagotomy ◽  
A New Technique ◽  
Alpha Chloralose ◽  
Histamine Challenge ◽  
Line Resistance ◽  
Reproducible Manner

A new technique using a monodispersed aerosol of histamine delivered to sublobar bronchi through a flexible fiber-optic bronchoscope was used to study the role of the vagus nerve and the effect of anesthesia in the response of collateral channels to exogenous histamine. Studies were performed in paralyzed dogs anesthetized with pentobarbital sodium or alpha-chloralose. Challenges with histamine aerosol were delivered to separate bronchi in each animal before and after bilateral cervical vagotomy. Resistance through collateral channels increased in a reproducible manner following histamine challenge. Vagotomy resulted in no significant change in base-line resistance through collateral channels. The response of collateral channels to exogenous histamine aerosol was not significantly affected by vagotomy or the type of anesthesia used. We conclude that vagal reflexes do not play a significant role in the response of collateral channels to exogenous histamine.

Posture effects on timing of abdominal muscle activity during stimulated ventilation

1999 ◽  
Vol 86 (6) ◽  
pp. 1994-2000 ◽  
Author(s):  
Tadashi Abe ◽  
Takumi Yamada ◽  
Tomoyuki Tomita ◽  
Paul A. Easton
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Moving Average ◽  
Abdominal Muscle ◽  
Transversus Abdominis ◽  
Emg Activity ◽  
Abdominal Muscles ◽  
External Oblique ◽  
End Tidal ◽  
Internal Oblique

In humans during stimulated ventilation, substantial abdominal muscle activity extends into the following inspiration as postexpiratory expiratory activity (PEEA) and commences again during late inspiration as preexpiratory expiratory activity (PREA). We hypothesized that the timing of PEEA and PREA would be changed systematically by posture. Fine-wire electrodes were inserted into the rectus abdominis, external oblique, internal oblique, and transversus abdominis in nine awake subjects. Airflow, end-tidal CO2, and moving average electromyogram (EMG) signals were recorded during resting and CO2-stimulated ventilation in both supine and standing postures. Phasic expiratory EMG activity (tidal EMG) of the four abdominal muscles at any level of CO2 stimulation was greater while standing. Abdominal muscle activities during inspiration, PEEA, and PREA, were observed with CO2stimulation, both supine and standing. Change in posture had a significant effect on intrabreath timing of expiratory muscle activation at any level of CO2stimulation. The transversus abdominis showed a significant increase in PEEA and a significant decrease in PREA while subjects were standing; similar changes were seen in the internal oblique. We conclude that changes in posture are associated with significant changes in phasic expiratory activity of the four abdominal muscles, with systematic changes in the timing of abdominal muscle activity during early and late inspiration.

Reflex control of abdominal muscles during positive-pressure breathing

1964 ◽  
Vol 19 (2) ◽  
pp. 224-232 ◽  
Author(s):  
Beverly Bishop
Keyword(s):  
Abdominal Muscle ◽  
Spinal Reflexes ◽  
The Other ◽  
Positive Pressure ◽  
Abdominal Muscles ◽  
Afferent Pathways ◽  
Muscle Response ◽  
Thoracic Spinal ◽  
Vagal Afferent ◽  
Continuous Positive Pressure

Continuous positive-pressure breathing initiates expiratory activity in the abdominal muscle and inhibits the diaphragm in anesthetized cats. This investigation defines neural mechanisms involved in this abdominal muscle response (AMR) to positive-pressure breathing. The AMR is not a segmental reflex since it is abolished by thoracic spinal transection. Bilateral rhizotomy (T8-L3) also eliminates AMR, but laparotomy and abdominal evisceration do not, suggesting that some neural inflow other than from abdominal muscle or viscera is necessary but insufficient for maintaining AMR. Abdominal vagotomy failed to interrupt AMR which was abolished by bilateral cervical vagotomy, indicating that the necessary receptors lie in the thorax. Compression or local anesthesia of the cervical vagi provided the experimental means for abolishing either the inhibition of the diaphragm or the AMR without necessarily interrupting the other. That one response may persist in the absence of the other indicates that vagal afferent pathways subserving AMR are distinct from those mediating diaphragm inhibition. Hence the active expiration of pressure breathing is not a simple corollary of the Hering-Breuer inflation reflex but is a separate reflex served by its own vagal pathway. abdominal muscle response; vagus control of active expiration; abdominal muscle motoneuron pool; vagal afferent pathway in pressure-breathing reflex; thoracic receptors; diaphragm response to pressure breathing; diaphragm; inspiration; expiratory reflexes; inspiratory reflexes; respiratory reflexes; segmental reflexes; spinal reflexes Submitted on February 21, 1963

Waterproofing EMG Instrumentation

2007 ◽  
Vol 8 (3) ◽  
pp. 195-201 ◽  
Author(s):  
Rebecca D. Benfield ◽  
Edward R. Newton ◽  
Tibor Hortobágyi
Keyword(s):  
Low Frequency ◽  
Surface Emg ◽  
Abdominal Muscle ◽  
Emg Activity ◽  
Abdominal Muscles ◽  
Buoyancy Effect ◽  
Noninvasive Method ◽  
Uterine Contractility ◽  
Human Labor ◽  
Dry And Wet Conditions

While still experimental, measurement of external uterine electromyographic (EMG) activity is a more sensitive and noninvasive method for measuring uterine contractility in human labor than the methods currently used in clinical practice. Hydrotherapy is purported to improve contractility in labor, yet there have been no reports of abdominal uterine EMG activity measured during immersion. To test telemetric EMG equipment and different waterproofing techniques under dry and immersed conditions, the authors recorded surface EMG activity from the abdominal muscles of 11 healthy, nonpregnant women, 22 to 51 years of age. After attaching one pair of electrodes to the skin on either side of the umbilicus and applying the waterproofing material, the authors tested the signal by asking participants to perform a short series of leg lifts while seated in a chair to evoke abdominal muscle contractions. They were then immersed to the chest in a hydrotherapy tub while performing two to three leg lifts over 60 s every 5 min for 60 min with 20 lb of weight suspended from their ankles to counteract the buoyancy effect of water. EMG activity was continuously recorded. They then repeated the dry-measures sequence. While waterproofing remained intact, EMG signals were essentially unchanged between dry and wet conditions. Of the 11 waterproofing applications tested, 10 failed at some point. In the data from the successful application, EMG signals in both channels exhibited stable baselines throughout and an absence of low-frequency artifact. The development of this technique allows for the recording of external uterine EMG activity during hydrotherapy. The authors have begun using it to investigate the effects of hydrotherapy on uterine contractility during human labor.

Sign in / Sign up

Export Citation Format

Share Document