Thyroid cartilage movements during breathing

1995 ◽  
Vol 78 (2) ◽  
pp. 441-448 ◽  
Author(s):  
T. C. Amis ◽  
A. Brancatisano ◽  
A. Tully
Keyword(s):  
Electrical Stimulation ◽  
Recurrent Laryngeal Nerve ◽  
Thyroid Cartilage ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
Electromyographic Activity ◽  
Tidal Breathing ◽  
Left And Right ◽  
Posterior Cricoarytenoid ◽  
Stimulation Of

We measured lateral (outward) thyroid cartilage displacement (TCD) of the larynx in six supine anesthetized (intravenous chloralose) dogs. Combined left and right TCDs were measured with linear transducers attached by a thread to the thyroid alae. During tidal breathing via a tracheostomy, phasic inspiratory TCD occurred in all dogs [0.66 +/- 0.2 mm (mean +/- SE)] together with phasic inspiratory electromyographic activity in the cricothyroid (CT) and posterior cricoarytenoid (PCA) muscles. During brief tracheal occlusions, TCD increased significantly to 1.27 +/- 0.2 mm (P = 0.001), accompanied by an increase of 95–115% in the peak CT and PCA electromyograms. Bilateral supramaximal electrical stimulation of the external branches of the superior laryngeal nerve (ExSLN) produced a TCD of 9.9 +/- 0.8 mm; however, similar stimulation of the recurrent laryngeal nerve (RLN) produced a TCD of only 1.33 +/- 0.1 mm (P = 0.0001). Furthermore, bilateral section of the ExSLN in five dogs significantly reduced tidal TCD by 48.7 +/- 24.4% (P < 0.05), and bilateral section of both the ExSLN and RLN resulted in slight phasic inward TCD (-0.06 +/- 0.05 mm). Thus, it appears that the activities of both the CT and RLN-innervated muscles (probably the PCA muscle) contribute to tidal breathing TCD. These findings suggest that inspiratory dilation of the hypopharynx is mediated by contractions of CT and PCA muscles.

Effects of Recurrent Laryngeal Nerve Transection and Vagotomy on Respiratory Contraction of the Cricothyroid Muscle

1989 ◽  
Vol 98 (5) ◽  
pp. 373-378 ◽  
Author(s):  
Gayle E. Woodson
Keyword(s):  
Recurrent Laryngeal Nerve ◽  
Superior Laryngeal Nerve ◽  
Upper Airway ◽  
Vocal Folds ◽  
Laryngeal Nerve ◽  
Electromyographic Activity ◽  
Airway Occlusion ◽  
Cricothyroid Muscle ◽  
Bilateral Vagotomy ◽  
Posterior Cricoarytenoid

The cricothyroid muscle (CT) appears to be an accessory muscle of respiration. Phasic inspiratory contraction is stimulated by increasing respiratory demand. Reflex activation of the CT may be responsible for the paramedian position of the vocal folds, and hence airway obstruction, in patients with bilateral recurrent laryngeal nerve (RLN) paralysis. Previous research has demonstrated the influence of superior laryngeal nerve (SLN) afferents on CT activity. The present study addresses the effects of vagal and RLN afferents. Electromyographic activity of the CT and right posterior cricoarytenoid muscle was monitored in anesthetized cats during tracheotomy breathing and in response to tracheal or upper airway occlusion in the intact animal. This was repeated following left RLN transection, bilateral vagotomy, and bilateral SLN transection. Vagotomy abolished CT response to tracheal occlusion and markedly reduced the response to upper airway occlusion. Vocal fold position following RLN transection appeared to correlate with CT activity; however, observed changes were minor.

Nitric oxide modulates elicitation of reflex swallowing from the pharynx in rats

2006 ◽  
Vol 291 (3) ◽  
pp. R651-R656 ◽  
Author(s):  
Hiroshi Kijima ◽  
Tomio Shingai ◽  
Yoshihiro Takahashi ◽  
Yuka Kajii ◽  
Shin-ichi Fukushima ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Electrical Stimulation ◽  
Intraperitoneal Administration ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
Electromyographic Activity ◽  
No Donor ◽  
Pharyngeal Branch ◽  
Prolonged Latency ◽  
Stimulation Of

The pharynx is very important for elicitation of reflex swallowing. The region of the pharynx is innervated by the pharyngeal branch of the glossopharyngeal nerve (GPN-ph). Nitric oxide (NO) plays an important role in various physiological functions. The purpose of this study is to investigate the contribution of NO to reflex swallowing evoked by electrical stimulation of the GPN-ph. Swallowing was evoked in urethane-anesthetized rats by application of repetitive electrical stimulation (10- to 20-μA amplitude, 10- to 20-Hz frequency, 1.0-ms duration) to the central cut end of the GPN-ph or superior laryngeal nerve. Swallowing was identified by electromyographic activity of the mylohyoid muscle. Latency to the first swallow and the interval between swallows were measured. Intravenous administration of NG-nitro-l-arginine (l-NNA, 0.6 mg/kg), a nonselective inhibitor of NO synthase (NOS), extremely prolonged latency to the first swallow and the interval between swallows evoked by the GPN-ph. Intraperitoneal administration of 7-nitroindazole (5.0 mg/kg), a selective inhibitor of neuronal NOS, significantly prolonged latency to the first swallow and the interval between swallows evoked by the GPN-ph. Administration of l-arginine (an NO donor, 500 mg/kg) and sodium nitroprusside (an NO releaser, 0.6 mg/kg) restored the suppression of swallowing induced by the NOS inhibitor. Superior laryngeal nerve-evoked swallowing was suppressed by administration of a higher dose of l-NNA (6.0 mg/kg). Swallowing evoked by water stimulation of the pharynx was also suppressed by l-NNA (0.6 mg/kg). These results suggest that NO plays an important role in signal processing for initiation of reflex swallowing from the pharynx.

Arterial Baroreceptor Fibers in the Recurrent Laryngeal Nerve

1973 ◽  
Vol 82 (2) ◽  
pp. 228-234 ◽  
Author(s):  
Stanley G. Strauss ◽  
Hiroyuki Fukuda ◽  
John A. Kirchner
Keyword(s):  
Blood Pressure ◽  
Recurrent Laryngeal Nerve ◽  
Aortic Arch ◽  
Thyroid Cartilage ◽  
Pressure Sensors ◽  
Superior Laryngeal Nerve ◽  
Nerve Fibers ◽  
Baroreceptor Reflex ◽  
Laryngeal Nerve ◽  
Stimulation Of

Stimulation of the larynx, as during intubation, can produce significant cardiac arrhythmias. Investigation of the cause of these arrhythmias has led us to believe that they are in part due to stimulation of a baroreceptor reflex pathway which passes through the larynx rather than to initiation of a simple reflex in the larynx itself. Pressure sensors (baroreceptors) in the aortic arch form part of a system which monitors systemic blood pressure. Stimulation of these baroreceptors produces, via a medullary reflex arc, a slowing of the heart rate, a decrease in sympathetic vascular tone, and as a result a drop in blood pressure. The pathway from the aortic arch baroreceptors has heretofore been thought to run directly through the vagus nerve. We have shown, however, that in the rat a significant number of fibers from aortic arch baroreceptors run in the left recurrent laryngeal nerve (RLN), through the larynx into the left superior laryngeal nerve (SLN), and only then into the vagus. Blocking or cutting the left RLN produces a significant drop in overall baroreceptor reflex activity, and furthermore, nerve fibers have been isolated in the left RLN which show exactly the same patterns of discharge as those from arterial baroreceptors elsewhere. It is our belief that at least some of the arrhythmias produced during laryngeal manipulation can be explained on the basis of mechanical compression producing stimulation of the baroreceptor fibers as they pass along the thyroid cartilage through the ramus communicans between the RLN and SLN. Further work needs to be done to show that compression does in fact stimulate the baroreceptor pathway, but there is now little doubt that, in experimental animals, such a pathway exists.

scholarly journals Chronic Electrical Stimulation of the Superior Laryngeal Nerve in the Rat: A Potential Therapeutic Approach for Postmenopausal Osteoporosis

Biomedicines ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 369
Author(s):  
Kaori Iimura ◽  
Nobuhiro Watanabe ◽  
Philip Milliken ◽  
Yee-Hsee Hsieh ◽  
Stephen J. Lewis ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Thyroid Gland ◽  
Venous Blood ◽  
Disease Model ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
Mineral Density ◽  
Ovx Rats ◽  
Chronic Electrical Stimulation ◽  
Stimulation Of

Electrical stimulation of myelinated afferent fibers of the superior laryngeal nerve (SLN) facilitates calcitonin secretion from the thyroid gland in anesthetized rats. In this study, we aimed to quantify the electrical SLN stimulation-induced systemic calcitonin release in conscious rats and to then clarify effects of chronic SLN stimulation on bone mineral density (BMD) in a rat ovariectomized disease model of osteoporosis. Cuff electrodes were implanted bilaterally on SLNs and after two weeks recovery were stimulated (0.5 ms, 90 microampere) repetitively at 40 Hz for 8 min. Immunoreactive calcitonin release was initially measured and quantified in systemic venous blood plasma samples from conscious healthy rats. For chronic SLN stimulation, stimuli were applied intermittently for 3–4 weeks, starting at five weeks after ovariectomy (OVX). After the end of the stimulation period, BMD of the femur and tibia was measured. SLN stimulation increased plasma immunoreactive calcitonin concentration by 13.3 ± 17.3 pg/mL (mean ± SD). BMD in proximal metaphysis of tibia (p = 0.0324) and in distal metaphysis of femur (p = 0.0510) in chronically SLN-stimulated rats was 4–5% higher than that in sham rats. Our findings demonstrate chronic electrical stimulation of the SLNs produced enhanced calcitonin release from the thyroid gland and partially improved bone loss in OVX rats.

Central GABAergic mechanisms are involved in apnea induced by SLN stimulation in piglets

2001 ◽  
Vol 90 (4) ◽  
pp. 1570-1576 ◽  
Author(s):  
Jalal M. Abu-Shaweesh ◽  
Ismail A. Dreshaj ◽  
Musa A. Haxhiu ◽  
Richard J. Martin
Keyword(s):  
Electrical Stimulation ◽  
Phrenic Nerve ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
Receptor Blocker ◽  
Inspiratory Time ◽  
Before And After ◽  
Four Levels ◽  
Stimulation Of

Stimulation of the superior laryngeal nerve (SLN) results in apnea in animals of different species, the mechanism of which is not known. We studied the effect of the GABAA receptor blocker bicuculline, given intravenously and intracisternally, on apnea induced by SLN stimulation. Eighteen 5- to 10-day-old piglets were studied: bicuculline was administered intravenously to nine animals and intracisternally to nine animals. The animals were anesthetized and then decerebrated, vagotomized, ventilated, and paralyzed. The phrenic nerve responses to four levels of electrical SLN stimulation were measured before and after bicuculline. SLN stimulation caused a significant decrease in phrenic nerve amplitude, phrenic nerve frequency, minute phrenic activity, and inspiratory time ( P < 0.01) that was proportional to the level of electrical stimulation. Increased levels of stimulation were more likely to induce apnea during stimulation that often persisted beyond cessation of the stimulus. Bicuculline, administered intravenously or intracisternally, decreased the SLN stimulation-induced decrease in phrenic nerve amplitude, minute phrenic activity, and phrenic nerve frequency ( P < 0.05). Bicuculline also reduced SLN-induced apnea and duration of poststimulation apnea ( P < 0.05). We conclude that centrally mediated GABAergic pathways are involved in laryngeal stimulation-induced apnea.

Function of the Posterior Cricoarytenoid Muscle in Phonation: In vivo Laryngeal Model

1993 ◽  
Vol 109 (6) ◽  
pp. 1043-1051 ◽  
Author(s):  
Hong-Shik Choi ◽  
Gerald S. Berke ◽  
Ming Ye ◽  
Jody Kreiman
Keyword(s):  
Recurrent Laryngeal Nerve ◽  
Fundamental Frequency ◽  
Nerve Stimulation ◽  
Sound Intensity ◽  
Vocal Folds ◽  
Laryngeal Nerve ◽  
Posterior Cricoarytenoid Muscle ◽  
Posterior Cricoarytenoid ◽  
Stimulation Of

The function of the posterior cricoarytenoid (PCA) muscle in phonation has not been well documented. To date, several electromyographic studies have suggested that the PCA muscle is not simply an abductor of the vocal folds, but also functions in phonation. This study used an in vivo canine laryngeal model to study the function of the PCA muscle. Subglottic pressure and electroglottographic, photogiottographic, and acoustic waveforms were gathered from five adult mongrel dogs under varying conditions of nerve stimulation. Subglottic pressure, fundamental frequency, sound intensity, and vocal efficiency decreased with increasing stimulation of the posterior branch of the recurrent laryngeal nerve. These results suggest that the PCA muscle not only acts to brace the larynx against the anterior pull of the adductor and cricothyroid muscles, but also functions inhibitorily in phonation by controlling the phonatory glottal width.

Transcutaneous Electrical Stimulation of the Recurrent Laryngeal Nerve in Monkeys

1987 ◽  
Vol 96 (1) ◽  
pp. 38-42 ◽  
Author(s):  
Ira Sanders ◽  
Jonathan Aviv ◽  
Michael M. Racenstein ◽  
Warren M. Kraus ◽  
Hugh F. Biller
Keyword(s):  
Electrical Stimulation ◽  
Recurrent Laryngeal Nerve ◽  
Vocal Cord ◽  
Laryngeal Nerve ◽  
Transcutaneous Electrical Stimulation ◽  
Direct Stimulation ◽  
Glottic Closure ◽  
Unilateral Stimulation ◽  
Tracheoesophageal Groove ◽  
Stimulation Of

The recurrent laryngeal nerve (RLN) of four anesthetized adult Macaca fascicularis monkeys was stimulated by applying current with blunt electrodes placed unilaterally and bilaterally on the intact neck skin along the tracheoesophageal groove. The stimulus consisted of 2.5- to 4.0-mA cathodal pulses, each of 1-ms duration, beginning at a frequency of 10 Hz and increasing by 10-Hz increments to 100 Hz. Unilateral stimulation from 10 to 30 Hz resulted in a graded vocal cord abduction, with the maximal glottic aperture occurring at 30 Hz. Stimulation above 30 Hz produced a graded cord adduction, with nearly complete glottic closure at 100 Hz; bilateral stimulation yielded similar results, with total glottic closure at 100 Hz. Confirmation of the RLN as mediator of this frequency-dependent cord motion was achieved by surgically isolating it and attaining identical results with direct stimulation. No cardiopulmonary alterations were observed in any trial. Transcutaneous electrical stimulation of the RLN seems to be a relatively safe, reliable, and noninvasive method of controlling vocal cord position and thereby the glottic airway in monkeys.

Effects of electrical stimulation of the superior laryngeal nerve on the jaw-opening reflex

2011 ◽  
Vol 1391 ◽  
pp. 44-53 ◽  
Author(s):  
Takako Fukuhara ◽  
Takanori Tsujimura ◽  
Yuka Kajii ◽  
Kensuke Yamamura ◽  
Makoto Inoue
Keyword(s):  
Electrical Stimulation ◽  
Superior Laryngeal Nerve ◽  
Laryngeal Nerve ◽  
Jaw Opening ◽  
Jaw Opening Reflex ◽  
Stimulation Of
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