Capsaicin-induced activation of pulmonary vagal C fibers produces reflex laryngeal closure in the rat

2006 ◽  
Vol 101 (4) ◽  
pp. 1104-1112 ◽  
Author(s):  
I-Jung Lu ◽  
Kun-Ze Lee ◽  
Ji-Chuu Hwang
Keyword(s):  
Intravenous Administration ◽  
Digital Camera ◽  
Vocal Folds ◽  
Emg Activity ◽  
Glottal Closure ◽  
C Fibers ◽  
Before And After ◽  
Subglottal Pressure ◽  
Male Wistar Rats ◽  
The Right

Our recent studies show that intravenous administration of capsaicin induces enhancement of the intralaryngeal thyroarytenoid (TA) branch but a reduction of the intralaryngeal abducent branch, suggesting that the glottis is likely closed by capsaicin. The aim of the present study was to examine whether the glottis is adducted by intravenous administration of capsaicin. Electromyographic (EMG) activity of the TA muscle, subglottal pressure (SGP), and glottal behavior were evaluated before and after intravenous administration of capsaicin in male Wistar rats that were anesthetized and tracheostomized. Catheters were placed in the femoral artery and vein, as well as in the right jugular vein. Low and high doses of capsaicin (0.625 and 1.25 μg/kg) produced apnea and increases in the amplitude of the TA EMG. This enhancement of the TA EMG was observed during apnea as well as during recovery from apnea. Moreover, the onset of the TA EMG was advanced such that it commenced earlier during inspiration. Concomitantly, the SGP substantially increased. Increases in both the TA EMG and SGP were abolished after bilateral sectioning of the recurrent laryngeal nerve. In some animals, movement of the vocal folds was recorded by taking a motion picture with a digital camera under a surgical microscope. With intravenous administration of capsaicin, a tight glottal closure, decreases in blood pressure, and bradycardia were observed. These results strongly suggest that glottal closure is reflexively induced by intravenous administration of capsaicin and that closure of the glottis is beneficial for the defense of the airway and lungs when an animal is exposed to environmental irritants.

Active upper airway closure during induced central apneas in lambs is complete at the laryngeal level only

2003 ◽  
Vol 95 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Pierre-Hugues Fortier ◽  
Philippe Reix ◽  
Julie Arsenault ◽  
Dominique Dorion ◽  
Jean-Paul Praud
Keyword(s):  
Upper Airway ◽  
Emg Activity ◽  
Airway Closure ◽  
Internal Branch ◽  
Laryngeal Nerves ◽  
Before And After ◽  
Subglottal Pressure ◽  
Central Apneas ◽  
Afferent Innervation ◽  
Stimulation Of

We tested the hypotheses that active upper airway closure during induced central apneas in nonsedated lambs 1) is complete and occurs at the laryngeal level and 2) is not due to stimulation of the superior laryngeal nerves (SLN). Five newborn lambs were surgically instrumented to record thyroarytenoid (TA) muscle (glottal constrictor) electromyographic (EMG) activity with supra- and subglottal pressures. Hypocapnic and nonhypocapnic central apneas were induced before and after SLN sectioning in the five lambs. A total of 174 apneas were induced, 116 before and 58 after sectioning of the internal branch of the SLN (iSLN). Continuous TA EMG activity was observed in 88% of apneas before iSLN section and in 87% of apneas after iSLN section. A transglottal pressure different from zero was observed in all apneas with TA EMG activity, with a mean subglottal pressure of 4.3 ± 0.8 cmH2O before and 4.7 ± 0.7 cmH2O after iSLN section. Supraglottal pressure was consistently atmospheric. Sectioning of both iSLNs had no effects on the results. We conclude that upper airway closure during induced central apneas in lambs is active, complete, and occurs at the glottal level only. Consequently, a positive subglottal pressure is maintained throughout the apnea. Finally, this complete active glottal closure is independent from laryngeal afferent innervation.

Carotid sinus nerve is involved in cardiorespiratory responses to intracarotid injection of capsaicin in the rat

2006 ◽  
Vol 100 (1) ◽  
pp. 60-66 ◽  
Author(s):  
Rurong Wang ◽  
Fadi Xu ◽  
Jianguo Zhuang ◽  
Cancan Zhang
Keyword(s):  
Carotid Sinus ◽  
Minute Ventilation ◽  
Right Atrial ◽  
Carotid Sinus Nerve ◽  
Cardiorespiratory Responses ◽  
C Fibers ◽  
Before And After ◽  
High Doses ◽  
The Right ◽  
Spontaneously Breathing

The carotid sinus nerve (CSN), important in cardiorespiratory modulation, mainly contains C fibers (CSCFs). Previous studies have demonstrated that selective stimulation of bronchopulmonary C fibers (PCFs) via right atrial injection of capsaicin (Cap; ∼0.25 μg) results in an apnea (∼3 s) associated with hypotension and bradycardia. The present study was undertaken to determine the effects of activating CSCFs on cardiorespiratory activities. Intracarotid injection of Cap was performed before and after bilateral transection of the CSN in anesthetized and spontaneously breathing rats. Our results showed that 1) low doses of Cap (up to 2 ng) produced an increase in minute ventilation by elevating both tidal volume and respiratory frequency with the threshold dosage at 1.0 ng ( P < 0.05); 2) high doses (4–64 ng) generated an apnea (prolongation of expiratory duration by ∼8-fold) and hypertension ( P < 0.05); 3) bilateral transection of the CSN reduced excitatory and inhibitory respiratory responses by 30 and 81%, respectively, and increased the hypertension by 88% ( P < 0.05); and 4) the same doses of Cap delivered into the right atrium to stimulate PCFs failed to evoke detectable cardiorespiratory responses. Our results suggest that compared with PCFs, CSCFs are more sensitive to Cap stimulation and that activation of these fibers significantly modulates cardiorespiratory activity in anesthetized rats.

scholarly journals Impact of Subharmonic and Aperiodic Laryngeal Dynamics on the Phonatory Process Analyzed in Ex Vivo Rabbit Models

2019 ◽  
Vol 9 (9) ◽  
pp. 1963 ◽  
Author(s):  
Fabian Thornton ◽  
Michael Döllinger ◽  
Stefan Kniesburges ◽  
David Berry ◽  
Christoph Alexiou ◽  
...  
Keyword(s):  
High Speed ◽  
Ex Vivo ◽  
Human Subjects ◽  
Voice Quality ◽  
Vocal Folds ◽  
Glottal Closure ◽  
Subglottal Pressure ◽  
Vocal Fold Dynamics ◽  
Cepstral Peak Prominence ◽  
Voice Pathologies

Normal voice is characterized by periodic oscillations of the vocal folds. On the other hand, disordered voice dynamics (e.g., subharmonic and aperiodic oscillations) are often associated with voice pathologies and dysphonia. Unfortunately, not all investigations may be conducted on human subjects; hence animal laryngeal studies have been performed for many years to better understand human phonation. The rabbit larynx has been shown to be a potential model of the human larynx. Despite this fact, only a few studies regarding the phonatory parameters of rabbit larynges have been performed. Further, to the best of our knowledge, no ex vivo study has systematically investigated phonatory parameters from high-speed, audio and subglottal pressure data with irregular oscillations. To remedy this, the present study analyzes experiments with sustained phonation in 11 ex vivo rabbit larynges for 51 conditions of disordered vocal fold dynamics. (1) The results of this study support previous findings on non-disordered data, that the stronger the glottal closure insufficiency is during phonation, the worse the phonatory characteristics are; (2) aperiodic oscillations showed worse phonatory results than subharmonic oscillations; (3) in the presence of both types of irregular vibrations, the voice quality (i.e., cepstral peak prominence) of the audio and subglottal signal greatly deteriorated compared to normal/periodic vibrations. In summary, our results suggest that the presence of both types of irregular vibration have a major impact on voice quality and should be considered along with glottal closure measures in medical diagnosis and treatment.

Training can improve muscle strength and endurance in 78- to 84-yr-old men

1992 ◽  
Vol 73 (6) ◽  
pp. 2517-2523 ◽  
Author(s):  
G. Grimby ◽  
A. Aniansson ◽  
M. Hedberg ◽  
G. B. Henning ◽  
U. Grangard ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Citrate Synthase ◽  
Vastus Lateralis ◽  
Knee Extension ◽  
Emg Activity ◽  
Vastus Lateralis Muscle ◽  
Neural Activation ◽  
Cross Sectional ◽  
Before And After ◽  
The Right

Nine men, 78–84 yr of age, participated in a dynamometer training program 2–3 times/wk, totaling 25 sessions, using voluntary maximal isometric, concentric, and eccentric right knee–extension actions (30 and 180 degrees/s). Measurements of muscle strength with a Kin-Com dynamometer and simultaneous electromyograms (EMG) were performed of both sides before and after the training period. Muscle biopsies were taken from the right vastus lateralis muscle. The total quadriceps cross-sectional area was measured with computerized tomography. Training led to an increase in maximal torque for concentric (10% at 30 degrees/s) and eccentric (13–19%) actions in the trained leg. The EMG activity increased at maximal eccentric activities. The total cross-sectional quadriceps area of the trained leg increased by 3%, but no changes were recorded in muscle fiber areas in these subjects, who already had large mean fiber areas (5.15 microns 2 x 10(3)). The fatigue index measured from 50 consecutive concentric contractions at 180 degrees/s decreased and the citrate synthase activity increased in all but one subject. The results demonstrate that increased neural activation accompanies an increase in muscle strength at least during eccentric action in already rather active elderly men and that muscle endurance may also be improved with training.

scholarly journals Modeling the Pathophysiology of Phonotraumatic Vocal Hyperfunction With a Triangular Glottal Model of the Vocal Folds

2017 ◽  
Vol 60 (9) ◽  
pp. 2452-2471 ◽  
Author(s):  
Gabriel E. Galindo ◽  
Sean D. Peterson ◽  
Byron D. Erath ◽  
Christian Castro ◽  
Robert E. Hillman ◽  
...  
Keyword(s):  
Vocal Fold ◽  
Muscle Activation ◽  
Maximum Flow ◽  
Vocal Folds ◽  
Element Model ◽  
Compensatory Mechanisms ◽  
Glottal Closure ◽  
Vocal Hyperfunction ◽  
Subglottal Pressure ◽  
Lumped Element Model

Purpose Our goal was to test prevailing assumptions about the underlying biomechanical and aeroacoustic mechanisms associated with phonotraumatic lesions of the vocal folds using a numerical lumped-element model of voice production. Method A numerical model with a triangular glottis, posterior glottal opening, and arytenoid posturing is proposed. Normal voice is altered by introducing various prephonatory configurations. Potential compensatory mechanisms (increased subglottal pressure, muscle activation, and supraglottal constriction) are adjusted to restore an acoustic target output through a control loop that mimics a simplified version of auditory feedback. Results The degree of incomplete glottal closure in both the membranous and posterior portions of the folds consistently leads to a reduction in sound pressure level, fundamental frequency, harmonic richness, and harmonics-to-noise ratio. The compensatory mechanisms lead to significantly increased vocal-fold collision forces, maximum flow-declination rate, and amplitude of unsteady flow, without significantly altering the acoustic output. Conclusion Modeling provided potentially important insights into the pathophysiology of phonotraumatic vocal hyperfunction by demonstrating that compensatory mechanisms can counteract deterioration in the voice acoustic signal due to incomplete glottal closure, but this also leads to high vocal-fold collision forces (reflected in aerodynamic measures), which significantly increases the risk of developing phonotrauma.

Effects of bilateral lesions of the dorsolateral funiculi and dorsal columns at the level of the low thoracic spinal cord on the control of locomotion in the adult cat. I. Treadmill walking

1996 ◽  
Vol 76 (2) ◽  
pp. 849-866 ◽  
Author(s):  
W. Jiang ◽  
T. Drew
Keyword(s):  
Spinal Cord ◽  
The Other ◽  
Emg Activity ◽  
Step Cycle ◽  
Testing Period ◽  
Left Limb ◽  
Before And After ◽  
Dorsal Columns ◽  
The Right ◽  
Bilateral Lesions

1. A quantitative and longitudinal analysis of locomotion was made after bilateral lesions of the dorsolateral funiculi (DLF) and/or the dorsal columns (DC) in the lower thoracic cord (T12 or T13) in five adult cats. All cats were chronically implanted several weeks before the spinal cord lesion to permit the recording of electromyographic (EMG) activity from selected flexor and extensor muscles of the fore- and hindlimbs of each side. This allowed each cat to act as its own control when comparing the pattern and amplitude of EMG activity before and after the lesion. All experiments were also videotaped to allow an analysis of the kinematic changes before and after the lesions. Kinematic data were only analyzed for the side of the cat facing the camera; for all cats this was the left side. 2. After recovery periods of 2-5 mo, wheat-germ-agglutinated horseradish peroxidase (WGA-HRP) was injected caudal to the lesion site (normally at L2). The extent of the lesion was verified both histologically and by evaluating the number of HRP-labeled neurons in different supraspinal structures. These analyses showed that the cortico- and rubrospinal tracts (CST and RST, respectively) were completely interrupted, bilaterally, in two of five of the cats; in one of these cats the DCs were also interrupted. In the other three cats there was more variable damage, and the CST and RST were only completely interrupted on the right side of one of these animals. The DCs were completely sectioned in two of these cats. 3. During the 1st wk subsequent to the lesion, most cats had difficulty in supporting their weight and in walking. However, within 10 days all were able to walk, unaided, for extended periods on the treadmill at speeds of at least 0.35 m/s. In the two cats with the complete, bilateral DLF lesions, the animals dragged both their left and right hindpaws along the treadmill belt during the swing phase of the step cycle (paw drag) throughout the testing period of 3-5 mo. In the other three cats, paw drag in either hindlimb was only seen in the 1st 2-3 wk after the lesions, with the exception of the cat with the complete lesion of the DLF on the right side, which showed sustained paw drag in the right hindlimb throughout the testing period. 4. Significant increases in step cycle and swing duration following the lesion were observed only in the two cats with the largest lesions. In all five cats, statistical comparisons of the slopes from a linear regression analysis showed that the relationship between swing and step cycle duration was unchanged by the lesions. 5. Joint angles in the left hindlimb of the two cats with the largest lesions were generally smaller (more flexed) than in the prelesion controls. This was particularly true for the knee and ankle joints. The other three cats showed changed joint angle values for the hip, knee, and ankle only in the 1st 2-3 wk after the lesions. All of the cats, except the one with the least damage to the left DLF, exhibited increased joint excursions at the metatarsophalangeal (MTP) joint of the left limb throughout the recovery period. 6. There were sustained changes in the coupling between the hip and the knee of the left limb, together with smaller changes in the coupling of the knee and ankle in the two cats with the complete lesions of the DLF. In contrast to the prelesion controls, flexion at the ankle occurred before swing onset in these same two cats. The changes in the coordination between the hip and the knee were associated with changes in the temporal coupling between the hip flexor, sartorius (Srt), and the knee flexor, semitendinosus (St). Despite some improvement, the coupling between these two muscles never fully recovered to the prelesion values. Similar, but smaller, changes in the delay between Srt and St were also seen in two of the other three cats. (ABSTRACT TRUNCATED)

scholarly journals Acute effect of the ischemic compression technique on the EMG activity of the muscle upper trapezius in subjects with myofascial trigger points

2020 ◽  
pp. 1-5
Author(s):  
Thomas Ângelo Miguel Gelmini ◽  
Patrícia Cilene Freitas Sant’Anna ◽  
William Dhein ◽  
Marcelo La Torre
Keyword(s):  
Trigger Points ◽  
Wilcoxon Test ◽  
Emg Activity ◽  
Myoelectric Activity ◽  
Compression Technique ◽  
Myofascial Trigger Points ◽  
Upper Trapezius ◽  
Significant Difference ◽  
Before And After ◽  
The Right

Background: Myofascial trigger points (MTP) are palpable painful nodules in a shortened area of a given muscle. The ischemic compression technique (IC), which consists of pressing the painful nodule until the elimination of tension or pain, has been shown to be an alternative for the treatment of MTP. The objective of this study was to analyze the influence of the IC technique on the level of pain to the palpation and electrical activity of the right upper trapezius (RUT) muscle during the elevation of the shoulder girdle and abduction of the shoulder in subjects with MTP. Methods: The sample consisted of ten subjects with mean age of 25.9 ± 2.68 years, who performed scapula elevation and right shoulder abduction up to 180º before and after the IC technique on the RUT muscle. The pain level was measured before and after the application of the IC technique and the myoelectric activity during the movements. Data analysis and processing were performed using the BIOMEC-SAS software and were presented in percentage values of the maximum voluntary isometric contraction (%MVIC). Statistical analysis were performed using the Wilcoxon test (α<0.05). Results: There was a significant increase in the mean% of activation (p=0.007) and in the peak %MVIC (p=0.005) of the myoelectric activity of the RUT muscle during the elevation movement of the right scapula. There was also a significant difference in the reduction of the level of pain referred to palpation (p=0.004). There were no differences during abduction movements. The calculation of the effect size showed that the IC technique had great influence on the results found in this study. Conclusion: The IC technique is an important resource for pain modulation and alteration of the myoelectric activity in MTP patients and can be used by physiotherapists when indicated.

Aerodynamic and Acoustic Voice Measures Before and After an Acute Public Speaking Stressor

2020 ◽  
Vol 63 (10) ◽  
pp. 3311-3325
Author(s):  
Brittany L. Perrine ◽  
Ronald C. Scherer
Keyword(s):  
Fundamental Frequency ◽  
Salivary Cortisol ◽  
Public Speaking ◽  
Stress System ◽  
Before And After ◽  
Subglottal Pressure ◽  
Response To Stress ◽  
System Activation ◽  
Speaking Fundamental Frequency ◽  
Pituitary Adrenal Axis

Purpose The goal of this study was to determine if differences in stress system activation lead to changes in speaking fundamental frequency, average oral airflow, and estimated subglottal pressure before and after an acute, psychosocial stressor. Method Eighteen vocally healthy adult females experienced the Trier Social Stress Test (TSST) to activate the hypothalamic–pituitary–adrenal axis. The TSST includes public speaking and performing mental arithmetic in front of an audience. At seven time points, three before the stressor and four after the stressor, the participants produced /pa/ repetitions, read the Rainbow Passage, and provided a saliva sample. Measures included (a) salivary cortisol level, (b) oral airflow, (c) estimated subglottal pressure, and (d) speaking fundamental frequency from the second sentence of the Rainbow Passage. Results Ten of the 18 participants experienced a hypothalamic–pituitary–adrenal axis response to stress as indicated by a 2.5-nmol/L increase in salivary cortisol from before the TSST to after the TSST. Those who experienced a response to stress had a significantly higher speaking fundamental frequency before and immediately after the stressor than later after the stressor. No other variable varied significantly due to the stressor. Conclusions This study suggests that the idiosyncratic and inconsistent voice changes reported in the literature may be explained by differences in stress system activation. In addition, laryngeal aerodynamic measures appear resilient to changes due to acute stress. Further work is needed to examine the influence of other stress systems and if these findings hold for dysphonic individuals.

Comparative Arterial Antithrombotic Activity of Clopidogrel and Acetyl Salicylic Acid in the Pig

1992 ◽  
Vol 68 (05) ◽  
pp. 500-505 ◽  
Author(s):  
Ch M Samama ◽  
Ph Bonnin ◽  
M Bonneau ◽  
G Pignaud ◽  
E Mazoyer ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Femoral Artery ◽  
Bleeding Time ◽  
Ex Vivo ◽  
Flow Reduction ◽  
Cyclic Flow ◽  
Left Femoral Artery ◽  
Before And After ◽  
The Right ◽  
Induced Aggregation

SummaryWe investigated the comparative antithrombotic properties of clopidogrel, an analogue of ticlopidine, and aspirin, using the Folts' model on femoral arteries in 22 pigs. On each animal, clopidogrel or aspirin were used to treat the thrombotic process on the left femoral artery and to prevent this process on the right femoral artery. Sequentially: an injury and stenosis were carried out on the left femoral artery; the thrombotic process was monitored with a Doppler during a 30-min observation period for cyclic flow reductions or permanent cessation of flow; after the first cyclic flow reduction occurred, clopidogrel (5 mg kg-1) or aspirin (2.5, 5, 100 mg kg-1) were injected intravenously; if cyclic flow reductions were abolished, epinephrine (0.4 µg kg-1 min-1) was injected to try to restore cyclic flow reductions and/or permanent cessation of flow; then injury and stenosis were applied on the right femoral artery. Before and after injection of clopidogrel or aspirin, ear immersion bleeding times and ex-vivo platelet aggregation were performed. Clopidogrel (n = 7) abolished cyclic flow reductions in all animals and epinephrine did not restore any cyclic flow reduction. On the right femoral artery, cyclic flow reductions were efficiently prevented, even for two injuries. Basal bleeding time (5 min 28) was lengthened (>15 min, 30 min after clopidogrel and remained prolonged even after 24 h). ADP-induced platelet aggregation was inhibited (more than 78%). Comparatively, aspirin had a moderate and no dose-dependent effect. Aspirin 2.5 mg kg-1 (n = 6) abolished cyclic flow reductions in 2 animals, CFR reoccurred spontaneously in one animal and epinephrine restored it in a second animal. Aspirin 5 mg kg-1 (n = 6) abolished cyclic flow reductions in only 3 animals and epinephrine always restored it. Aspirin 100 mg kg-1 (n = 3) was unable to abolish cyclic flow reductions. On the right femoral artery, aspirin did not significantly prevent cyclic flow reductions which occurred in all animals after one (n = 14) or two injuries (n = 1), except for one animal. Basal bleeding time was lengthened but it shortened rapidly, reaching its basal value after 24 h. ADP-induced aggregation was not significantly inhibited, whereas arachidonic acid induced aggregation was always inhibited. Clopidogrel appears as a more potent antithrombotic drug than aspirin in this model, in treating and preventing spontaneous or epinephrine-induced cyclic flow reductions and lengthening bleeding time.

EFEKTIVITAS METODE DEMONSTRASI DALAM MENINGKATKAN HASIL BELAJAR SISWA SEKOLAH MENENGAH KEJURUAN PADA PENGAJARAN SISTEM KOLOID

2013 ◽  
Vol 19 (1) ◽  
pp. 28
Author(s):  
Hamda Situmorang ◽  
Manihar Situmorang
Keyword(s):  
High School ◽  
High School Students ◽  
Abstract Concept ◽  
Vocational High School ◽  
School Students ◽  
Lecture Method ◽  
Colloid System ◽  
Before And After ◽  
The Right ◽  
And Control

Abstract Implementation of demonstration method in the teaching of chemistry is assigned as the right strategy to improve students’ achievement as it is proved that the method can bring an abstract concept to reality in the class. The study is conducted to vocational high school students in SMKN1 Pargetteng getteng Sengkut Pakfak Barat at accademic year 2013. The teaching has been carried out three cycles on the teaching of chemistry topic of colloid system. In the study, the class is divided into two class, experiment class and control class. The demontration method is used to teach students in experimental class while the teaching in control class is conducted with lecture method. Both are evaluated by using multiple choise tests before and after the teaching procedures, and the ability of students to answer the problems are assigned as students’ achievements. The results showed that demonstration method improved students’ achievement in chemistry. The students in experimental class who are taughed with demonstration method (M=19.08±0.74) have higher achievements compare with control class (M=12.91±2.52), and both are significantly different (tcalculation 22.85 > ttable 1.66). The effectivity of demostration method in experimental class (97%) is found higer compare to conventional method in control class (91%).

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