Respiratory function of hyoid muscles and hyoid arch

The position of the hyoid arch suggests that it supports soft tissue surrounding the upper airway (UA) and can act to maintain UA patency. We also suspected that muscles inserting on the hyoid arch might show respiratory patterns of activity that could be affected by respiratory stimuli. To test these possibilities, we moved the hyoid arch ventrally in six anesthetized dogs either by traction on it or by stimulation of hyoid muscles. UA resistance was decreased 73 +/- (SE) 6% and 72 +/- 6% by traction and stimulation during expiration and 57 +/- 15% and 52 +/- 8% during inspiration. Moving averages of the geniohyoid (GH) and thyrohyoid (TH) obtained in six other dogs breathing 100% O2 showed phasic respiratory activity while the sternohyoid (SH) showed phasic respiratory activity in only two of these animals and no activity in four. With progressive hypercapnia, GH and TH increased as did SH when activity was already present. Airway occlusion at end expiration augmented and prolonged inspiratory activity in the hyoid muscles but did not elicit SH activity if not already present. Occlusion at end inspiration suppressed phasic activity in hyoid muscles for as long as in the diaphragm. After vagotomy activity increased and became almost exclusively inspiratory. Activity appeared in SH when not previously present. Duration and amplitude of hyoid muscle activity were increased with negative UA pressure and augmented breaths. We conclude that the hyoid arch and muscles can strongly affect UA flow resistance. Hyoid muscles show responses to chemical, vagal, and negative pressure stimuli similar to other UA muscles.

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Effect of Chemoreceptor and Pulmonary Receptor Stimulation on Dilator Nares EMG Activity in the Dog

Otolaryngology ◽

10.1177/019459988309100611 ◽

1983 ◽

Vol 91 (6) ◽

pp. 648-652 ◽

Cited By ~ 2

Author(s):

Daniel J. Blum ◽

Thomas V. McCaffrey

Keyword(s):

Upper Airway ◽

Emg Activity ◽

Receptor Stimulation ◽

Lung Inflation ◽

Anesthetized Dogs ◽

Inspiratory Activity ◽

Upper Airway Muscles ◽

The Relationship ◽

Pulmonary Stretch Receptor ◽

Stimulation Of

To define the relationship between central control of upper airway muscles and respiratory muscle function, the electromyographic responses of the dilator nares muscles to stimulation of chemoreceptors and pulmonary receptors were studied in six anesthetized dogs. Only at maximal levels of hypoxia was the inspiratory activity of the dilator nares significantly increased. Hypercapnic stimulation increased the inspiratory activity with each incremental increase in CO2. Pulmonary stretch receptor stimulation produced by lung inflation inhibited dilator nares activity. Pulmonary irritant receptor stimulation by intravenously administered histamine increased dilator nares activity, as did pulmonary J receptor stimulation by the intravenous administration of capsaicin.

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Effect of posture, route of respiration, and negative pressure on palatal muscle activity in humans

Journal of Applied Physiology ◽

10.1152/jappl.1995.79.2.448 ◽

1995 ◽

Vol 79 (2) ◽

pp. 448-454 ◽

Cited By ~ 35

Author(s):

I. L. Mortimore ◽

R. Mathur ◽

N. J. Douglas

Keyword(s):

Negative Pressure ◽

Muscle Activity ◽

Respiratory Activity ◽

Maximum Activity ◽

Electromyographic Activity ◽

Airway Narrowing ◽

Pressure Application ◽

Supine Posture ◽

Inspiratory Activity ◽

Male Subjects

Sleep apnea is worse in the supine posture and is associated with retropalatal airway narrowing or occlusion. We have, therefore, examined the effects of posture, negative pressure, and route of respiration on palatal muscle activity in 13 nonsnoring awake male subjects by using electromyography. Electromyographic activity of the levator palatini and palatoglossus was expressed as a percentage of maximum activity. Both the levator palatini (P = 0.002) and palatoglossus (P = 0.002) exhibited phasic inspiratory activity. Overall, posture did not affect the levator palatini (F = 1.58; P = 0.23) or palatoglossus (F = 0.98; P = 0.34) activity, but analysis by route of respiration showed the palatoglossus to be more active when the subjects were nose breathing supine (F = 6.64; P = 0.02). Levator palatini activity was lower when nose breathing was compared with mouth breathing in both the erect and supine postures (F = 6.67; P < 0.02). Nose breathing with the mouth held open caused an increase in palatoglossal activity (P = 0.04). Negative-pressure application (0 to -12.5 cmH2O) caused significant increases in levator palatini (P < 0.001) and palatoglossus (P < 0.001) activity, 100 ms after pressure stimulus, irrespective of route. However, the palatoglossus required significantly greater negative pressures to cause activation when applied via the nose compared with the mouth (P < 0.05). These observations indicate that the levator palatini and palatglossus have respiratory activity and are reflexly activated by negative pressure.

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Nasal and laryngeal reflex responses to negative upper airway pressure

Journal of Applied Physiology ◽

10.1152/jappl.1984.56.3.746 ◽

1984 ◽

Vol 56 (3) ◽

pp. 746-752 ◽

Cited By ~ 96

Author(s):

E. van Lunteren ◽

W. B. Van de Graaff ◽

D. M. Parker ◽

J. Mitra ◽

M. A. Haxhiu ◽

...

Keyword(s):

Negative Pressure ◽

Muscle Activity ◽

Moving Average ◽

Superior Laryngeal Nerve ◽

Upper Airway ◽

Laryngeal Nerve ◽

Topical Anesthesia ◽

Inspiratory Activity ◽

Posterior Cricoarytenoid ◽

Upper Airway Muscles

The effects of negative pressure applied to just the upper airway on nasal and laryngeal muscle activity were studied in 14 spontaneously breathing anesthetized dogs. Moving average electromyograms were recorded from the alae nasi (AN) and posterior cricoarytenoid (PCA) muscles and compared with those of the genioglossus (GG) and diaphragm. The duration of inspiration and the length of inspiratory activity of all upper airway muscles was increased in a graded manner proportional to the amount of negative pressure applied. Phasic activation of upper airway muscles preceded inspiratory activity of the diaphragm under control conditions; upper airway negative pressure increased this amount of preactivation. Peak diaphragm activity was unchanged with negative pressure, although the rate of rise of muscle activity decreased. The average increases in peak upper airway muscle activity in response to all levels of negative pressure were 18 +/- 4% for the AN, 27 +/- 7% for the PCA, and 122 +/- 31% for the GG (P less than 0.001). Rates of rise of AN and PCA electrical activity increased at higher levels of negative pressure. Nasal negative pressure affected the AN more than the PCA, while laryngeal negative pressure had the opposite effect. The effects of nasal negative pressure could be abolished by topical anesthesia of the nasal passages, while the effects of laryngeal negative pressure could be abolished by either topical anesthesia of the larynx or section of the superior laryngeal nerve. Electrical stimulation of the superior laryngeal nerve caused depression of AN and PCA activity, and hence does not reproduce the effects of negative pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

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Do canine scalene and sternomastoid muscles play a role in breathing?

Journal of Applied Physiology ◽

10.1152/jappl.1994.76.1.242 ◽

1994 ◽

Vol 76 (1) ◽

pp. 242-252 ◽

Cited By ~ 21

Author(s):

A. De Troyer ◽

M. Cappello ◽

J. F. Brichant

Keyword(s):

Respiratory Function ◽

Respiratory Drive ◽

Airway Occlusion ◽

Single Breath ◽

Large Numbers ◽

Inspiratory Resistance ◽

Cervical Vagotomy ◽

Inspiratory Activity ◽

Unanesthetized Animals ◽

Spontaneously Breathing

To assess the respiratory function of the scalene and sternomastoid muscles in the dog, we studied the effect of graded increases in inspiratory airflow resistance and single-breath airway occlusion on the electrical activity of these muscles in 18 supine anesthetized spontaneously breathing animals. The sternomastoids never showed any activity, and the scalenes showed some inspiratory activity during occlusion in only two animals. The adoption of the prone position and bilateral cervical vagotomy did not affect this pattern. Hypercapnia also did not elicit any sternomastoid activity and induced scalene inspiratory activity during occlusion in only four of nine animals. On microscopic examination, however, both muscles were found to contain large numbers of spindles, suggesting that they have the capacity to respond to stretch. In addition, with increases in inspiratory resistance, both the sternum and ribs were displaced in the caudal direction. As a result, the scalenes demonstrated a gradual inspiratory lengthening and the normal inspiratory lengthening of the sternomastoids was accentuated. Additional studies in three unanesthetized animals showed consistent activity in the scalene and sternomastoid muscles during movements of the trunk and neck but no activity during breathing, including occluded breathing. These observations thus indicate that the alpha-motoneurons of the scalene and sternomastoid muscles in the dog have very small central respiratory drive potentials with respect to their critical firing threshold. In this animal, these muscles do not have a significant respiratory function.

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Thoracic influence on upper airway patency

Journal of Applied Physiology ◽

10.1152/jappl.1988.65.5.2124 ◽

1988 ◽

Vol 65 (5) ◽

pp. 2124-2131 ◽

Cited By ~ 226

Author(s):

W. B. Van de Graaff

Keyword(s):

Muscle Activity ◽

Upper Airway ◽

Constant Flow ◽

Airway Patency ◽

Anesthetized Dogs ◽

Measured Resistance ◽

Flow Through ◽

Phrenic Nerves ◽

Tracheostomy Tubes ◽

Spontaneously Breathing

Patency of the upper airway (UA) is usually considered to be maintained by the activity of muscles in the head and neck. These include cervical muscles that provide caudal traction on the UA. The thorax also applies caudal traction to the UA. To observe whether this thoracic traction can also improve UA patency, we measured resistance of the UA (RUA) during breathing in the presence and absence of UA muscle activity. Fifteen anesthetized dogs breathed through tracheostomy tubes. RUA was calculated from the pressure drop of a constant flow through the isolated UA. RUA decreased 31 +/- 5% (SEM) during inspiration. After hyperventilating seven of these dogs to apnea, we maximally stimulated the phrenic nerves to produce paced diaphragmatic breathing. Despite absence of UA muscle activity, RUA fell 51 +/- 11% during inspiration. Graded changes were produced by reduced stimulation. In six other dogs we denervated all UA muscles. RUA still fell 25 +/- 7% with inspiration in these spontaneously breathing animals. When all caudal ventrolateral cervical structures mechanically linking the thorax to the UA were severed, RUA increased and respiratory fluctuations ceased. These findings indicate that tonic and phasic forces generated by the thorax can improve UA patency. Inspiratory increases in UA patency cannot be attributed solely to activity of UA muscles.

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Posterior cricoarytenoid muscle activity during wakefulness and sleep in normal adults

Journal of Applied Physiology ◽

10.1152/jappl.1990.68.4.1746 ◽

1990 ◽

Vol 68 (4) ◽

pp. 1746-1754 ◽

Cited By ~ 38

Author(s):

S. T. Kuna ◽

J. S. Smickley ◽

G. Insalaco

Keyword(s):

Vocal Cord ◽

Muscle Activity ◽

Upper Airway ◽

Nrem Sleep ◽

Tonic Activity ◽

Quiet Breathing ◽

Phasic Activity ◽

Inspiratory Activity ◽

Posterior Cricoarytenoid ◽

Normal Adults

Six normal adults were studied 1) to compare respiratory-related posterior cricoarytenoid (PCA) muscle activity during wakefulness and sleep and 2) to determine the effect of upper airway occlusions during non-rapid-eye-movement (NREM) sleep on PCA activity. A new electromyographic technique was developed to implant hooked-wire electrodes into the PCA by using a nasopharyngoscope. A previously described technique was used to induce upper airway occlusions during NREM sleep (Kuna and Smickley, J. Appl. Physiol. 64: 347-353, 1988). The PCA exhibited phasic inspiratory activity during quiet breathing in wakefulness and sleep in all subjects. Discounting changes in tonic activity, peak amplitude of PCA inspiratory activity during stage 3-4 NREM sleep decreased to 77% of its value in wakefulness. Tonic activity throughout the respiratory cycle was present in all subjects during wakefulness but was absent during state 3-4 NREM sleep. In this sleep stage, PCA phasic activity abruptly terminated near the end of inspiration. During nasal airway occlusions in NREM sleep, PCA phasic activity did not increase significantly during the first or second occluded effort. The results, in combination with recent findings for vocal cord adductors in awake and sleeping adults, suggest that vocal cord position during quiet breathing in wakefulness is actively controlled by simultaneously acting antagonistic intrinsic laryngeal muscles. In contrast, the return of the vocal cords toward the midline during expiration in stage 3-4 NREM sleep appears to be a passive phenomenon.

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Upper airway muscle activity during nasal occlusion in newborn babies

Journal of Applied Physiology ◽

10.1152/jappl.1989.66.3.1328 ◽

1989 ◽

Vol 66 (3) ◽

pp. 1328-1335 ◽

Cited By ~ 13

Author(s):

G. Cohen ◽

D. J. Henderson-Smart

Keyword(s):

Gestational Age ◽

Muscle Activity ◽

Upper Airway ◽

Airway Closure ◽

Term Infants ◽

Airway Occlusion ◽

Postmenstrual Age ◽

Preterm Babies ◽

The Stability ◽

Upper Airway Muscles

Submental electromyorgams (SM EMG) were recorded from 20 preterm babies (gestational age 30 +/- 2 wk, postmenstrual age at study 35 +/- 2 wk) (mean +/- SD) and 3 full-term infants (7–14 days old). SM EMG was evaluated during eupnea and brief experimental airway occlusion. Phasic inspiratory SM EMG was rarely seen during eupnea. SM EMG tended to increase on the first occluded effort, although this increase was not statistically significant in most babies. All infants showed progressive breath-by-breath augmentation of phasic SM EMG during occlusions in rapid-eye-movement (REM) as well as quiet (QS) sleep; phasic increases in SM EMG were similar during REM and QS occlusions in the majority (16/22) of babies. Periods of airway closure were detected during 24 occlusions in 5 infants; phasic SM EMG was reduced on these occasions. The results are consistent with the idea that recruitment of upper airway muscles contributes to the stability of the airway of the preterm human.

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Changes in end-expiratory lung volume during sleep in patients with occlusive apnea

Journal of Applied Physiology ◽

10.1152/jappl.1987.63.4.1642 ◽

1987 ◽

Vol 63 (4) ◽

pp. 1642-1647 ◽

Cited By ~ 14

Author(s):

R. M. Aronson ◽

C. G. Alex ◽

E. Onal ◽

M. Lopata

Keyword(s):

Lung Volume ◽

Muscle Activity ◽

Upper Airway ◽

Nrem Sleep ◽

Esophageal Pressure ◽

Inspiratory Pressure ◽

Upper Airways ◽

Airway Occlusion ◽

Respiratory Inductive Plethysmography ◽

Inductive Plethysmography

Eight patients with occlusive sleep apnea were monitored during non-rapid-eye-movement (NREM) sleep to study the factors that contribute to negative inspiratory pressure generation and thus upper airway occlusion. End-expiratory lung volume assessed by respiratory inductive plethysmography [sum of end-expiratory levels (SUM EEL)] increased early and decreased late during the ventilatory phases (P less than 0.0001, one-way analysis of variance). Inspiratory change in esophageal pressure (Pes) and peak inspiratory diaphragmatic and genioglossal electromyograms (EMGdi and EMGge) decreased while the inspiratory pressure generated for a given diaphragmatic activity (Pes/EMGdi) increased during the preapneic phase (P less than 0.0001, for all). Multiple regression analysis with Pes/EMGdi as the dependent variable (R2 = 0.90) indicated that both the changes in SUM EEL and EMGge significantly contributed to the model (P less than 0.008 and 0.004, respectively). These results indicate that end-expiratory lung volume fluctuates during NREM sleep in patients with occlusive apnea and suggest that these changes along with the changes in upper airway muscle activity contribute to the generation of negative inspiratory pressure, leading to the passive collapse of the upper airways.

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Modulation of laryngeal and respiratory pump muscle activities with upper airway pressure and flow

Journal of Applied Physiology ◽

10.1152/jappl.2001.91.2.897 ◽

2001 ◽

Vol 91 (2) ◽

pp. 897-904 ◽

Cited By ~ 8

Author(s):

M. H. Stella ◽

S. J. England

Keyword(s):

Negative Pressure ◽

Muscle Activity ◽

Upper Airway ◽

Abdominal Muscle ◽

Positive Pressure ◽

Emg Activity ◽

Posterior Cricoarytenoid ◽

Spontaneously Breathing ◽

Respiratory Muscle Activity ◽

Stimulation Of

The hypothesis that upper airway (UA) pressure and flow modulate respiratory muscle activity in a respiratory phase-specific fashion was assessed in anesthetized, tracheotomized, spontaneously breathing piglets. We generated negative pressure and inspiratory flow in phase with tracheal inspiration or positive pressure and expiratory flow in phase with tracheal expiration in the isolated UA. Stimulation of UA negative pressure receptors with body temperature air resulted in a 10–15% enhancement of phasic moving-time-averaged posterior cricoarytenoid electromyographic (EMG) activity above tonic levels obtained without pressure and flow in the UA (baseline). Stimulation of UA positive pressure receptors increased phasic moving-time-averaged thyroarytenoid EMG activity above tonic levels by 45% from baseline. The same enhancement of posterior cricoarytenoid or thyroarytenoid EMG activity was observed with the addition of flow receptor stimulation with room temperature air. Tidal volume and diaphragmatic and abdominal muscle activity were unaffected by UA flow and/or pressure, whereas respiratory timing was minimally affected. We conclude that laryngeal afferents, mainly from pressure receptors, are important in modulating the respiratory activity of laryngeal muscles.

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