Ventilatory and Upper Airway Muscle Responses to Upper Airway CO2 in Anaesthetized Neonatal Guinea-Pigs

1996 ◽  
pp. 449-452 ◽  
Author(s):  
A. K. Curran ◽  
K. D. O’Halloran ◽  
A. Bradford
Keyword(s):  
Guinea Pigs ◽  
Upper Airway ◽  
Muscle Responses

Respiratory muscle responses to changes in chemoreceptor drive in infants

1990 ◽  
Vol 68 (3) ◽  
pp. 1041-1047 ◽  
Author(s):  
W. A. Carlo ◽  
J. M. DiFiore
Keyword(s):  
Preterm Infants ◽  
Respiratory Muscle ◽  
Muscle Activation ◽  
Respiratory Muscles ◽  
Upper Airway ◽  
Obstructive Apnea ◽  
Surface Electrodes ◽  
Posterior Cricoarytenoid ◽  
Upper Airway Muscles ◽  
Muscle Responses

Upper airway muscles and the diaphragm may have different quantitative responses to chemoreceptor stimulation. To compare the respiratory muscle responses to changes in CO2, 10 ventilator-dependent preterm infants (gestational age 28 +/- 1 wk, postnatal age 40 +/- 6 days, weight 1.4 +/- 0.1 kg) were passively hyperventilated to apnea and subsequently hypoventilated. Electromyograms from the genioglossus, alae nasi, posterior cricoarytenoid, and diaphragm were recorded from surface electrodes. Apneic CO2 thresholds of all upper airway muscles (genioglossus 46.8 +/- 4.3 Torr, alae nasi 42.4 +/- 3.6 Torr, posterior cricoarytenoid 41.6 +/- 3.2 Torr) were higher than those of the diaphragm (38.8 +/- 2.6 Torr, all P less than 0.05). Above their CO2 threshold levels, responses of all upper airway muscles appeared proportional to those of the diaphragm. We conclude that nonproportional responses of the respiratory muscles to hypercapnia may be the result of differences in their CO2 threshold. These differences in CO2 threshold may cause imbalance in respiratory muscle activation with changes in chemical drive, leading to upper airway instability and obstructive apnea.

scholarly journals The role of trigeminal nasal TRPM8-expressing afferent neurons in the antitussive effects of menthol

2013 ◽  
Vol 115 (2) ◽  
pp. 268-274 ◽  
Author(s):  
J. Plevkova ◽  
M. Kollarik ◽  
I. Poliacek ◽  
M. Brozmanova ◽  
L. Surdenikova ◽  
...  
Keyword(s):  
Citric Acid ◽  
Guinea Pigs ◽  
Upper Airway ◽  
Afferent Neurons ◽  
Tracheal Mucosa ◽  
Upper Airways ◽  
Cold Temperatures ◽  
Cold Sensitive ◽  
Lower Airways

The cold-sensitive cation channel TRPM8 is a target for menthol, which is used routinely as a cough suppressant and as an additive to tobacco and food products. Given that cold temperatures and menthol activate neurons through gating of TRPM8, it is unclear how menthol actively suppresses cough. In this study we describe the antitussive effects of (−)-menthol in conscious and anesthetized guinea pigs. In anesthetized guinea pigs, cough evoked by citric acid applied topically to the tracheal mucosa was suppressed by menthol only when it was selectively administered as vapors to the upper airways. Menthol applied topically to the tracheal mucosa prior to and during citric acid application or administered continuously as vapors or as an aerosol to the lower airways was without effect on cough. These actions of upper airway menthol treatment were mimicked by cold air delivered to the upper airways but not by (+)-menthol, the inactive isomer of menthol, or by the TRPM8/TRPA1 agonist icilin administered directly to the trachea. Subsequent molecular analyses confirmed the expression of TRPM8 in a subset of nasal trigeminal afferent neurons that do not coincidently express TRPA1 or TRPV1. We conclude that menthol suppresses cough evoked in the lower airways primarily through a reflex initiated from the nose.

Cricothyroid muscle responses to increased chemical drive in awake normal humans

1991 ◽  
Vol 70 (5) ◽  
pp. 2233-2241 ◽  
Author(s):  
J. R. Wheatley ◽  
A. Brancatisano ◽  
L. A. Engel
Keyword(s):  
Lead Time ◽  
Upper Airway ◽  
Inspiratory Flow ◽  
Inspiratory Time ◽  
Cricothyroid Muscle ◽  
Inspiratory Muscles ◽  
Inspiratory Activity ◽  
Normal Humans ◽  
Muscle Responses ◽  
Muscle Ct

To examine the response of the cricothyroid muscle (CT) to increased chemical drive, we measured its electromyogram simultaneously with that of the alae nasi (AN) in seven normal awake subjects. During both progressive hyperoxic hypercapnia and hypoxia, peak integrated inspiratory activity (moving time average, MTA) of the CT and AN increased as a power function of mean inspiratory flow (ratio of tidal volume to inspiratory time, VT/TI), given by MTA = a(VT/TI)b + c (where a, b, and c are constants). The exponent b varied from 0.009 to 3.4 among subjects but was correlated between CT and AN both during hypercapnia (r = 0.86) and hypoxia (r = 0.81). The onset of inspiratory activity of the CT and AN preceded that of inspiratory flow. Expressed as a percentage of expiratory time, the CT lead time rose from 7% at rest to 20% during hyperpnea. The corresponding values for the AN were from 22 to 52% (both P less than 0.03). Thus the pattern of response of the CT and AN is similar and related to that of the inspiratory muscles in a curvilinear manner. The findings suggest that during chemical stimulation the electrical activity of the CT is analogous to that of the AN, an upper airway dilator.

Soft palate muscle responses to negative upper airway pressure

1999 ◽  
Vol 86 (2) ◽  
pp. 523-530 ◽  
Author(s):  
T. C. Amis ◽  
N. O’Neill ◽  
J. R. Wheatley ◽  
T. van der Touw ◽  
E. di Somma ◽  
...  
Keyword(s):  
Soft Palate ◽  
Muscle Activity ◽  
Airway Pressure ◽  
Upper Airway ◽  
Emg Activity ◽  
Afferent Activity ◽  
Afferent Pathways ◽  
Levator Veli Palatini ◽  
Anesthetized Dogs ◽  
Muscle Responses

The afferent pathways and upper airway receptor locations involved in negative upper airway pressure (NUAP) augmentation of soft palate muscle activity have not been defined. We studied the electromyographic (EMG) response to NUAP for the palatinus, tensor veli palatini, and levator veli palatini muscles in 11 adult, supine, tracheostomized, anesthetized dogs. NUAP was applied to the nasal or laryngeal end of the isolated upper airway in six dogs and to four to six serial upper airway sites from the nasal cavity to the subglottis in five dogs. When NUAP was applied at the larynx, peak inspiratory EMG activity for the palatinus and tensor increased significantly ( P< 0.05) and plateaued at a NUAP of −10 cmH2O. Laryngeal NUAP failed to increase levator activity consistently. Nasal NUAP did not increase EMG activity for any muscle. Consistent NUAP reflex recruitment of soft palate muscle activity only occurred when the larynx was exposed to the stimulus and, furthermore, was abolished by bilateral section of the internal branches of the superior laryngeal nerves. We conclude that soft palate muscle activity may be selectively modulated by afferent activity originating in the laryngeal and hypopharyngeal airway.

Chronic Intermittent Asphyxia Impairs Rat Upper Airway Muscle Responses to Acute Hypoxia and Asphyxia

CHEST Journal ◽  
2002 ◽  
Vol 122 (1) ◽  
pp. 269-275 ◽  
Author(s):  
Ken D. O’Halloran ◽  
Michelle McGuire ◽  
Turlough O’Hare ◽  
Aidan Bradford
Keyword(s):  
Acute Hypoxia ◽  
Upper Airway ◽  
Muscle Responses

Upper airway and respiratory muscle responses to continuous negative airway pressure

1989 ◽  
Vol 66 (3) ◽  
pp. 1373-1382 ◽  
Author(s):  
R. M. Aronson ◽  
E. Onal ◽  
D. W. Carley ◽  
M. Lopata
Keyword(s):  
Eye Movement ◽  
Airway Pressure ◽  
Minute Ventilation ◽  
Upper Airway ◽  
Normal Subjects ◽  
Rapid Eye Movement ◽  
Rapid Eye Movement Sleep ◽  
Airway Patency ◽  
Negative Airway Pressure ◽  
Muscle Responses

To determine upper airway and respiratory muscle responses to nasal continuous negative airway pressure (CNAP), we quantitated the changes in diaphragmatic and genioglossal electromyographic activity, inspiratory duration, tidal volume, minute ventilation, and end-expiratory lung volume (EEL) during CNAP in six normal subjects during wakefulness and five during sleep. During wakefulness, CNAP resulted in immediate increases in electromyographic diaphragmatic and genioglossal muscle activity, and inspiratory duration, preserved or increased tidal volume and minute ventilation, and decreased EEL. During non-rapid-eye-movement and rapid-eye-movement sleep, CNAP was associated with no immediate muscle or timing responses, incomplete or complete upper airway occlusion, and decreased EEL. Progressive diaphragmatic and genioglossal responses were observed during non-rapid-eye-movement sleep in association with arterial O2 desaturation, but airway patency was not reestablished until further increases occurred with arousal. These results indicate that normal subjects, while awake, can fully compensate for CNAP by increasing respiratory and upper airway muscle activities but are unable to do so during sleep in the absence of arousal. This sleep-induced failure of load compensation predisposes the airways to collapse under conditions which threaten airway patency during sleep. The abrupt electromyogram responses seen during wakefulness and arousal are indicative of the importance of state effects, whereas the gradual increases seen during sleep probably reflect responses to changing blood gas composition.

Respiratory-related activity of soft palate muscles: augmentation by negative upper airway pressure

1994 ◽  
Vol 76 (1) ◽  
pp. 424-432 ◽  
Author(s):  
T. Van der Touw ◽  
N. O'Neill ◽  
A. Brancatisano ◽  
T. Amis ◽  
J. Wheatley ◽  
...  
Keyword(s):  
Soft Palate ◽  
Airway Pressure ◽  
Upper Airway ◽  
Substantial Contribution ◽  
Emg Activity ◽  
Nasal Breathing ◽  
Related Activity ◽  
Tracheal Pressure ◽  
Upper Airway Muscles ◽  
Muscle Responses

We studied respiratory-related activity of the soft palate muscles in 10 anesthetized tracheostomized supine dogs. Moving time average (MTA) electromyographic (EMG) activity was measured in the palatinus (PAL), levator veli palatini (LP), and tensor veli palatini (TP) with bipolar fine-wire electrodes and in the diaphragm with bipolar hook electrodes. Measurements were made during tracheostomy breathing and nasal breathing with the mouth sealed (NB). During tracheostomy breathing, all soft palate muscles displayed respiratory-related phasic inspiratory and expiratory as well as tonic EMG activity. During NB, peak inspiratory EMG activity increased in PAL, LP, and TP because of an increase in both phasic inspiratory and tonic MTA activity. In contrast, phasic expiratory activity did not change. A constant negative pressure equal to peak inspiratory tracheal pressure during NB was applied to the caudal end of the isolated upper airway with the nose occluded. This was associated with soft palate muscle responses qualitatively similar to the responses during NB but accounted for only 39, 25, and 32% of the magnitude of the peak inspiratory MTA EMG responses to NB in PAL, LP, and TP, respectively. Our results demonstrate that the soft palate muscles exhibit respiratory-related activity in common with other upper airway muscles. Furthermore, such activity is augmented in each soft palate muscle during NB, and negative upper airway pressure makes a substantial contribution to the recruitment of soft palate muscle activity.

Sign in / Sign up

Export Citation Format

Share Document