Stimulation of rapidly adapting pulmonary stretch receptors by pulmonary lymphatic obstruction in dogs

1988 ◽  
Vol 66 (5) ◽  
pp. 630-636 ◽  
Author(s):  
K. Ravi ◽  
K. K. Teo ◽  
C. T. Kappagoda
Keyword(s):  
Airway Pressure ◽  
Dynamic Compliance ◽  
Lymph Flow ◽  
Venous Congestion ◽  
Vascular Space ◽  
Airway Mechanics ◽  
Stretch Receptors ◽  
Pulmonary Stretch Receptors ◽  
Stimulation Of ◽  
Lymphatic Obstruction

The effects of pulmonary lymphatic obstruction and pulmonary venous congestion on the activities of slowly adapting receptors (SAR) and rapidly adapting receptors (RAR) of the airways were examined in anaesthetized, artificially ventilated dogs. In 11 out of 12 RAR (12 dogs) examined, pulmonary lymphatic obstruction for a period of 20 min produced a sustained significant increase in activity without a significant change in peak airway pressure and dynamic compliance. The activity remained significantly elevated even after the pulmonary lymphatic obstruction was released. This stimulus was without effect on the SAR (n = 5 dogs). Pulmonary venous congestion alone increased the RAR activity (n = 7 dogs) significantly without producing significant changes in airway mechanics. Lymphatic obstruction, when superimposed upon congestion, did not produce a further significant increase in activity. In four dogs the effect of pulmonary venous congestion (left atrial pressure increased from 7.6 ± 1.7 to 16.3 ± 2.7 mmHg) (1 mmHg = 133.3 Pa) on pulmonary lymphatic flow was examined. The procedure caused a significant increase in lymph flow. These results suggest that in the dog, the RAR activity is influenced by changes in the pulmonary extra vascular space.

Consequences of capsaicin treatment on pulmonary vagal reflexes and chemoreceptor activity in lambs

2000 ◽  
Vol 89 (5) ◽  
pp. 1709-1718 ◽  
Author(s):  
Véronique Diaz ◽  
Julie Arsenault ◽  
Jean-Paul Praud ◽  
Keyword(s):  
Ventilatory Response ◽  
Ventilatory Responses ◽  
Body Activity ◽  
Pulmonary Receptor ◽  
Stretch Receptors ◽  
C Fiber ◽  
Pulmonary Stretch Receptors ◽  
Bolus Intravenous Injection ◽  
To Receive ◽  
Stimulation Of

The aim of this study was to test the hypothesis that capsaicin treatment in lambs selectively inhibits bronchopulmonary C-fiber function but does not alter other vagal pulmonary receptor functions or peripheral and central chemoreceptor functions. Eleven lambs were randomized to receive a subcutaneous injection of either 25 mg/kg capsaicin (6 lambs) or solvent (5 lambs) under general anesthesia. Capsaicin-treated lambs did not demonstrate the classical ventilatory response consistently observed in response to capsaicin bolus intravenous injection in control lambs. Moreover, the ventilatory responses to stimulation of the rapidly adapting pulmonary stretch receptors (intratracheal water instillation) and slowly adapting pulmonary stretch receptors (Hering-Breuer inflation reflex) were similar in both groups of lambs. Finally, the ventilatory responses to various stimuli and depressants of carotid body activity and to central chemoreceptor stimulation (CO2 rebreathing) were identical in control and capsaicin-treated lambs. We conclude that 25 mg/kg capsaicin treatment in lambs selectively inhibits bronchopulmonary C-fiber function without significantly affecting the other vagal pulmonary receptor functions or that of peripheral and central chemoreceptors.

Reflex control of the tracheal vasculature of sheep

1993 ◽  
Vol 75 (5) ◽  
pp. 2173-2179 ◽  
Author(s):  
S. E. Webber ◽  
J. G. Widdicombe
Keyword(s):  
Carotid Body ◽  
Muscle Tone ◽  
Intravenous Injections ◽  
Stretch Receptors ◽  
Pulmonary Stretch Receptors ◽  
Before And After ◽  
Cervical Trachea ◽  
Carotid Body Chemoreceptors ◽  
Reflex Stimulation ◽  
Stimulation Of

Arteries to the cervical trachea were perfused at constant flow in anesthetized sheep. Perfusion pressures (PP), blood pressure (BP), and changes in tracheal smooth muscle tone (Ptr) were measured. Stimulation of pulmonary C-fiber receptors decreased PP (-6.5%) and BP (-16.8%) and increased Ptr (+61.5%), changes prevented by vagotomy and therefore reflex. Stimulation of cardiac receptors and slowly adapting pulmonary stretch receptors decreased PP (-7.9%) and BP (-21.0) and increased Ptr (+19.0%), changes reversed by vagotomy and therefore reflex. Stimulation and inhibition of slowly adapting pulmonary stretch receptors had no vagal-dependent effect on PP and BP, but inflation decreased (-20.3%) and deflation increased Ptr (+35.2%), effects abolished by vagotomy and therefore reflex. Systemic hypoxia increased PP and BP before and after vagotomy (+12.2 and +40.3%), effects greatly reduced by cutting the carotid body nerves; it increased Ptr (+29.8%), an effect abolished by vagotomy and cutting the carotid body nerves. Systemic hypercapnia increased PP (+16.9%), BP (+20.5%), and Ptr (+36.2%), the first two responses being unaffected by vagotomy and the last almost abolished. Stimulation of carotid body chemoreceptors by KCN increased PP (+22.5%), BP (+104.7%), and Ptr (+8.5%), all responses prevented by cutting the carotid body nerves. Responses to intravenous injections of KCN were similar.

Multireceptor activation of the pulmonary chemoreflex

1991 ◽  
Vol 70 (1) ◽  
pp. 368-370 ◽  
Author(s):  
E. B. Strong ◽  
J. F. Green
Keyword(s):  
Breathing Pattern ◽  
Right Atrial ◽  
Direct Stimulation ◽  
C Fibers ◽  
Stretch Receptors ◽  
Pulmonary Stretch Receptors ◽  
Shallow Breathing ◽  
Rapid Shallow Breathing ◽  
Stimulation Of ◽  
Secondary Stimulation

Schertel et al. (J. Appl. Physiol. 61: 1237–1240, 1984) reported that pulmonary C fibers initiate the prompt apnea followed by rapid shallow breathing evoked by pulmonary arterial injections of capsaicin. However, doubt has remained as to whether these changes in breathing pattern are induced exclusively by direct stimulation of pulmonary C fibers or whether secondary stimulation of slowly adapting pulmonary stretch receptors by capsaicin-induced reflex bronchoconstriction also contributes to the response. To determine the contribution of this secondary mechanism to changes in breathing pattern, we evoked the pulmonary chemoreflex in spontaneously breathing dogs before and after blockade of muscarinic receptors with atropine. Right atrial injections of capsaicin before the administration of atropine induced a classical pulmonary chemoreflex, i.e., apnea, hypotension, and bradycardia followed by rapid shallow breathing and bronchoconstriction. After atropine, all components of the pulmonary chemoreflex induced by right atrial injections of capsaicin remained intact except bronchoconstriction. However, the absolute magnitude of the change in each component of the reflex except apnea was significantly attenuated. We conclude that the classic pulmonary chemoreflex is a complex phenomenon initiated primarily by stimulation of pulmonary C fibers but significantly influenced by secondary stimulation of slowly adapting pulmonary stretch receptors.

Influence of CPAP on reflex responses to tracheal irritation in anesthetized humans

1989 ◽  
Vol 67 (3) ◽  
pp. 954-958 ◽  
Author(s):  
T. Nishino ◽  
K. Sugimori ◽  
K. Hiraga ◽  
Y. Hond
Keyword(s):  
Airway Pressure ◽  
Positive Airway Pressure ◽  
Lung Inflation ◽  
Cough Reflex ◽  
Reflex Responses ◽  
Stretch Receptors ◽  
Pulmonary Stretch Receptors ◽  
Spontaneously Breathing ◽  
Different Levels ◽  
Reflex Cough

We investigated the effects of lung inflation during continuous positive airway pressure breathing (CPAP) on airway defensive reflexes in 10 enflurane-anesthetized spontaneously breathing humans. The airway defensive reflexes were induced by instillation into the trachea of 0.5 ml of distilled water at two different levels of end-expiratory pressure (0 and 10 cmH2O CPAP). The tracheal irritation at an end-expiratory pressure of 0 cmH2O caused a variety of reflex responses including apnea, spasmodic panting, expiration reflex, cough reflex, an increase in heart rate, and an increase in blood pressure. Lung inflation during CPAP of 10 cmH2O did not exert any influence on these reflex responses in terms of the types, latencies, and durations of reflex responses although the intensity of the expiration reflex and cough reflex was augmented by lung inflation. Our results suggest that the pulmonary stretch receptors do not play an important role in the mechanisms of airway defensive reflexes in humans.

Substance P antagonist does not block the stimulation of rapidly adapting pulmonary stretch receptors by ammonia

Lung ◽  
1994 ◽  
Vol 172 (1) ◽  
Author(s):  
S. Matsumoto ◽  
M. Yamasaki ◽  
T. Kanno ◽  
T. Nagayama ◽  
M. Tanno ◽  
...  
Keyword(s):  
Substance P ◽  
Substance P Antagonist ◽  
Stretch Receptors ◽  
Pulmonary Stretch Receptors ◽  
Stimulation Of

Acute inhalation of ozone stimulates bronchial C-fibers and rapidly adapting receptors in dogs

1993 ◽  
Vol 74 (5) ◽  
pp. 2345-2352 ◽  
Author(s):  
J. C. Coleridge ◽  
H. M. Coleridge ◽  
E. S. Schelegle ◽  
J. F. Green
Keyword(s):  
Lung Compliance ◽  
Acute Exposure ◽  
Ozone Exposure ◽  
C Fibers ◽  
Stretch Receptors ◽  
Pulmonary Stretch Receptors ◽  
Lower Trachea ◽  
Afferent Response ◽  
Vagal Cooling ◽  
Stimulation Of

To identify the afferents responsible for initiating the vagally mediated respiratory changes evoked by acute exposure to ozone, we recorded vagal impulses in anesthetized, open-chest, artificially ventilated dogs and examined the pulmonary afferent response to ozone (2–3 ppm in air) delivered to the lower trachea for 20–60 min. Bronchial C-fibers (BrCs) were the lung afferents most susceptible to ozone, the activity of 10 of 11 BrCs increasing from 0.2 +/- 0.2 to 4.6 +/- 1.3 impulses/s within 1–7 min of ozone exposure. Ten of 15 rapidly adapting receptors (RARs) were stimulated by ozone, their activity increasing from 1.5 +/- 0.4 to 4.7 +/- 0.7 impulses/s. Stimulation of RARs (but not of BrCs) appeared secondary to the ozone-induced reduction of lung compliance because it was abolished by hyperinflation of the lungs. Ozone had little effect on pulmonary C-fibers or slowly adapting pulmonary stretch receptors. Our results suggest that both BrCs and RARs contribute to the tachypnea and bronchoconstriction evoked by acute exposure to ozone when vagal conduction is intact and that BrCs alone are responsible for the vagally mediated tachypnea that survives vagal cooling to 7 degrees C.

The Control of Changes in Peripheral Sensilla Associated with Feeding in Locusta Migratoria (L.)

1972 ◽  
Vol 57 (3) ◽  
pp. 755-763
Author(s):  
E. A. BERNAYS ◽  
R. F. CHAPMAN
Keyword(s):  
Normal Level ◽  
Electrical Resistance ◽  
Locusta Migratoria ◽  
Corpus Cardiacum ◽  
Corpora Cardiaca ◽  
Diuretic Hormone ◽  
Stretch Receptors ◽  
The Brain ◽  
Maxillary Palps ◽  
Stimulation Of

1. The electrical resistance across the tips of the maxillary palps is not affected by stimulation of the palps, but increases to the normal level found after feeding as a result of distension of the foregut with agar or injection of corpus cardiacum homogenates into the haemolymph. 2. No increase in resistance occurs if the posterior pharyngeal nerves or the frontal connectives are cut. 3. It is inferred that distension of the foregut stimulates stretch receptors which, acting via the posterior pharyngeal nerves, the frontal connectives and the brain, cause the release of hormone from the storage lobes of the corpora cardiaca. This hormone acts on the terminal sensilla of the palps, causing them to close and so increasing the resistance across the palps. 4. Release of the diuretic hormone is controlled via the same pathway.

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