Respiratory-related pharyngeal constrictor muscle activity in awake goats

O’Halloran, Ken D.; Herman, Jay K.; Bisgard, G. E.

doi:10.1016/s0034-5687(99)00026-2

Cited by 14 publications

(10 citation statements)

References 31 publications

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“…In awake unsedated goats, the TP and HP were phasically active during expiration. Similar results have been reported in awake goats and lambs by O'Halloran et al (25) and Praud et al (28,29). In unsedated cats, Murikami and Kirchner (24) reported phasic HP expiratory activity, whereas the TP exhibited tonic activity throughout inspiration and expiration, with a phasic increase during expiration.…”

Section: Eupneasupporting

confidence: 88%

“…A third potential cause of TP and HP difference relates to the motoneurons supplying the HP and TP, which are differently distributed in the dorsomedial subgroup of the compact cell group of the nucleus ambiguus (19). Accordingly, the difference in discharge intensity between the TP and HP suggests that the pharyngeal constrictors may not be homogeneous in terms of control and possible function, which has been suggested previously (25).…”

Section: Eupneamentioning

confidence: 77%

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Reciprocal activation of hypopharyngeal muscles and their effect on upper airway area

Feroah

Forster²,

Pan

et al. 2000

Journal of Applied Physiology

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We examined in awake goats, 1) with intact upper airways (UAW), the effect of altering chemical drive on pharyngeal constrictors [thyropharyngeus (TP) and hypopharyngeus (HP)] and a dilator [stylopharyngeus (SP)], and 2) with an isolated UAW, the effect of activation of these muscles on supraglottic UAW (UAW(SG)) area. During eupnea in nine goats with intact UAW, the TP and HP were active during expiration, whereas the SP exhibited tonic expiratory and phasic inspiratory activity. After mechanically induced apneas (MIA), TP activity increased (263%, P < 0.02), HP activity exhibited a small, varied response, and SP activity greatly decreased (10%, P < 0.02). During resumption of respiratory effort, all goats exhibited absent/reduced airflow, and when diaphragm activity was 95% of control, TP activity remained elevated (135%) and SP activity was reduced (56%, P < 0.02). During hypercapnia, 1) TP activity decreased (P < 0.02), 2) HP response varied, and 3) SP activity increased (P < 0.02). After MIA in six goats with isolated UAW, TP activity increased 198% (P < 0.02) and UAW(SG) area (endoscopically determined) decreased (to 15% of control, P < 0.02). During recovery from MIA, a correlation was found between UAW(SG) area and the ratio of SP to TP activity. We conclude that the reciprocal activation of mechanically opposing dilator and constrictor muscles in the hypopharynx is correlated to changes in the UAW(SG) area, and an imbalance in activity of these opposing muscles can lead to UAW(SG) narrowing.

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Section: Eupneasupporting

confidence: 88%

Section: Eupneamentioning

confidence: 77%

Reciprocal activation of hypopharyngeal muscles and their effect on upper airway area

Feroah

Forster²,

Pan

et al. 2000

Journal of Applied Physiology

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“…The available data either suggest that there is no modulation or, if present, that the activity is primarily during the expiratory phase of the respiratory cycle (23) . Although little is known about whether the pharyngeal constrictor muscles are stimulated by negative pressure, stimulation by hypoxia or hypercapnia results in the emergence of strong phasic expiratory activity in both human and animal studies (23, 37–40) . Interestingly, experimental data in animals suggest that the activity of these muscles constricts the airway and reduces its diameter at normal and high low volumes.…”

Section: Pharyngeal Muscle Groups and Their Respiratory Modulationmentioning

confidence: 99%

Control of the pharyngeal musculature during wakefulness and sleep: Implications in normal controls and sleep apnea

Edwards

White

2011

Head & Neck

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Respiration involves the complex coordination of several pump and upper airway/pharyngeal muscles. From a respiratory perspective, the major function of the pharyngeal muscles is to keep the airway patent allowing for airflow in and out of the lung with minimal work by the respiratory pump muscles. The activity of each of the pharyngeal muscles varies depending on its function, but many reduce their activity during sleep. In healthy individuals, these muscles can respond to respiratory stimuli during sleep in order to prevent airway collapse. However, in individuals with an anatomically small airway, the muscles cannot always compensate for the increased mechanical load. Thus, a vulnerable situation in which the airway is prone to collapse may occur with the development of obstructive sleep apnea (OSA). The present article describes the current understanding regarding the control of the pharyngeal musculature during wakefulness and sleep, as well as the implications for OSA.

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“…It is well recognized that the IPC plays an important role in upper-airway functions during swallowing (Basmajian and Dutta, 1961a;Kawasaki et al, 1964;Elidan et al, 1990), respiration (Rowe et al, 1984;Sherrey et al, 1986;Praud et al, 1996;O'Halloran et al, 1999;Feroah et al, 2000), and voice production (Ueda et al, 1972;Shin et al, 1981).…”

mentioning

confidence: 99%

“…However, it exhibits phasic expiratory activity during progressive hypercapnia and hypoxia (Kuna, 2000). Animal experiments showed that the IPC exhibits phasic expiratory activity in awake rhesus monkeys (Rowe et al, 1984), goats and lambs (Praud et al, 1996;O'Halloran et al, 1999;Feroah et al, 2000), and rabbits (Basmajian and Dutta, 1961b;Rothstein et al, 1983). In awake dogs (Kawasaki et al, 1964) and cats (Murakami and Kirchner, 1974), the IPC exhibits tonic activity throughout the entire respiratory cycle, with a phasic increase during expiration.…”

mentioning

confidence: 99%

Neuromuscular compartments and fiber‐type regionalization in the human inferior pharyngeal constrictor muscle

Sanders

2001

Anat. Rec.

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The inferior pharyngeal constrictor (IPC) muscle functions during swallowing, respiration, and vocalization. The most-caudal portion of the IPC is believed to be part of the functional upper esophageal sphincter (UES). We hypothesized that the caudal fibers of the human IPC may have enzyme-histochemical characteristics similar to those of the cricopharyngeus muscle, a major component of the UES. In this study, human IPC muscles obtained from autopsy were studied using Sihler's stain to examine innervation patterns, and using myofibrillar ATPase, NADH tetrazolium reductase (NADH-TR), and succinic dehydrogenase (SDH) techniques to investigate the distribution and oxidative capacity of the slow-(type I) and fast-(type II) twitch fibers in the muscle. The results showed that the human IPC consists of at least two neuromuscular compartments (NMCs): rostral and caudal. Each of the NMCs was innervated by a separate nerve branch derived from the pharyngeal branch of the vagus nerve. The rostral NMC is faster (39% type I, 61% type II) than the caudal NMC (70% type I, 30% type II). In addition, two histochemically-delineated fiber layers were identified in the human IPC: a slow inner layer (SIL) with predominantly type I fibers (66%), and a fast outer layer (FOL) with predominantly type II fibers (62%) (P Ͻ 0.01). However, the dimensions of both fiber layers and proportions of the muscle fiber types varied with the NMCs. Specifically, the ratio of the thickness of the SIL to FOL was ϳ2:1 for the caudal NMC and ϳ1:2 for the rostral NMC, respectively. In the SIL the type I fibers accounted for 84% for the caudal NMC and 69% and 44% for the lower and upper portions of the rostral NMC. In contrast, the type II fibers in the FOL accounted for 46% for the caudal NMC and 67% and 74% for the lower and upper portions of the rostral NMC, respectively (P Ͻ 0.01). The caudal NMC of the IPC shared histochemical characteristics with the cricopharyngeus muscle, in that it contained predominantly slow oxidative fibers. Overall, the caudal NMC and the SIL in the IPC had high NADH-TR and SDH activities. However, different patterns of oxidative enzyme activity were identified in both type I and type II fibers. This study provided histochemical evidence for the concept that the caudal NMC within the IPC contributes to the functional UES. In addition, the two histochemically-defined fiber layers in the IPC may be a specialized adaptation in humans to enable different upper-airway functions during respiration, swallowing, and speech. Anat

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Respiratory-related pharyngeal constrictor muscle activity in awake goats

Cited by 14 publications

References 31 publications

Reciprocal activation of hypopharyngeal muscles and their effect on upper airway area

Reciprocal activation of hypopharyngeal muscles and their effect on upper airway area

Control of the pharyngeal musculature during wakefulness and sleep: Implications in normal controls and sleep apnea

Neuromuscular compartments and fiber‐type regionalization in the human inferior pharyngeal constrictor muscle

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