The effect of the resistance loading of inspiration and expiration on pulmonary stretch receptor discharge

Davenport, Paul W.; Frazier, Donald T.; Zechman, F. W.

doi:10.1016/0034-5687(81)90111-0

Cited by 50 publications

(28 citation statements)

References 14 publications

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“…The ventilatory response to ERL or SF 6 breathing observed in intact and spinal cats corroborates numerous observations in the same species, which have also shown that the prolongation of inspiration in response to inspiratory or total resistive loading results mainly from the changes in vagal afferent pathways [6,18,21,22,24,28]. The mechanism of inspiratory lengthening was ascribed to decreased pulmonary stretch receptor discharge with inspiratory resistors, with the consequence of reduced inhibitory influences to medullary inspiratory neurons [6].…”

Section: Changes In Breathing Patternsupporting

confidence: 70%

Comparisons among external resistive loading, drug-induced bronchospasm, and dense gas breathing in cats: Roles of vagal and spinal afferents

Barrière¹,

Delpierre²,

Volgo³

et al. 1993

Lung

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In anesthetized cats, breathing spontaneously, increase in lung resistance (RL) was induced by either external resistive loads (ERL) or internal loading produced by dense gas breathing (sulfur hexafluoride, SF6) or serotonin (5-HT)-induced bronchoconstriction. The 3 test agents were used in each animal. Arterial blood gases were maintained in the normal range. Ventilatory and cardiovascular responses were studied in 3 groups of animals: intact, vagotomized, or spinalized at C8 level, a condition that preserved diaphragmatic afferents. In intact or spinal animals, ERL as well as SF6 inhalation lengthened the inspiratory and/or the expiratory periods, whereas 5-HT injections elicited rapid shallow breathing. The changes in ventilatory timing with either type of load were not observed in vagotomized cats. In all animals, ERL breathing or 5-HT injections increased the moving-time average of diaphragmatic EMG measured at constant time (Edi 0.1 and 0.5 secs), but this was not observed during SF6 inhalation, a condition in which the magnitude of RL increase was less than in the 2 other situations. The changes in systemic arterial blood pressure and/or cardiac frequency were mostly associated with 5 HT-induced bronchoconstriction. They persisted in spinalized cats, but were not observed or reversed in vagotomized ones. These observations demonstrate that vagal afferents play a major role in the changes in ventilatory timing and cardiovascular function in response to both external or internal moderate resistive loading. The existence of Edi changes in the 3 groups of cats suggests also that diaphragmatic afferents, preserved in both situations, are involved in this response.

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Section: Changes In Breathing Patternsupporting

confidence: 70%

Comparisons among external resistive loading, drug-induced bronchospasm, and dense gas breathing in cats: Roles of vagal and spinal afferents

Barrière¹,

Delpierre²,

Volgo³

et al. 1993

Lung

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“…The variability in Vy was in contrast to the responses described in anaesthetized cats [Davenport et al, 1981], in which V| de creased as T| increased. This may reflect less effect of pulmonary stretch receptor input in man, or merely the cognitive com ponent.…”

Section: Discussioncontrasting

confidence: 44%

Alveolar Gas Pressure Changes with Resistive Loads in Man

Hornstein¹,

Ledsome²

1984

Respiration

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Respiratory responses to a single breath during which a resistive load was applied were studied in 8 conscious subjects. There was an increase in inspiratory time (T₁), an increase in end-tidal Pco₂ (P_ETco₂) and a decrease in end-tidal Po₂ (PetO₂) on the resisted breath. 12 subjects were given a single inspiration of a mixture of air containing increased CO₂ and reduced O₂. This gas mixture induced changes in P_ETCO₂ and P_ETO₂ approximately double those seen with the resistive loads. There was no change in tidal volume (V_T), T₁ or expiratory time during the first breath. During the following breath there was a small increase in T₁ and V_T· The results indicate that although resistive loading may cause changes in PetCCCO₂ and P_ETO₂, these changes are unlikely to contribute to the respiratory responses during the first loaded breath.

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“…This load compensation response has been reported in anesthetized animals using external resistive loads to breathing and is characterized by the recruitment of respiratory muscle activity, an increase in breath duration, and a decrease in tidal volume (6,8,(13)(14)(15)(16)57). Depending on the timing within the breath phase of the added resistive load (end-inspiratory vs. endexpiratory), inspiratory or expiratory duration is increased.…”

Section: Itto Load Compensationmentioning

confidence: 74%

Tracheal occlusion modulates the gene expression profile of the medial thalamus in anesthetized rats

Bernhardt¹,

García-Reyero

Vovk³

et al. 2011

Journal of Applied Physiology

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scious awareness of breathing requires the activation of higher brain centers and is believed to be a neural gated process. The thalamus could be responsible for the gating of respiratory sensory information to the cortex. It was reasoned that if the thalamus is the neural gate, then tracheal obstructions will modulate the gene expression profile of the thalamus. Anesthetized rats were instrumented with an inflatable cuff sutured around the trachea. The cuff was inflated to obstruct 2-4 breaths, then deflated for a minimum of 15 breaths. Obstructions were repeated for 10 min followed by immediate dissection of the medial thalamus. Following the occlusion protocol, 588 genes were found to be altered (P Ͻ 0.05; log2 fold change Ն 0.4), with 327 genes downregulated and 261 genes upregulated. A significant upregulation of the serotonin HTR2A receptor and significant downregulation of the dopamine DRD1 receptor genes were found. A pathway analysis was performed that targeted serotonin and dopamine receptor pathways. The mitogen-activated protein kinase 1 (MAPK1) gene was significantly downregulated. MAPK1 is an inhibitory regulator of HTR2A and facilitatory regulator for DRD1. Downregulation of MAPK1 may be related to the significant upregulation of HTR2A and downregulation of DRD1, suggesting an interaction in the medial thalamus serotonin-dopamine pathway elicited by airway obstruction. These results demonstrate an immediate change in gene expression in thalamic arousal, fear, anxiety motivation-related serotonin and dopamine receptors in response to airway obstruction. The results support the hypothesis that the thalamus is a component in the respiratory mechanosensory neural pathway. respiratory loading; microarray; stress; serotonin; dopamine THE RESPIRATORY SYSTEM is continually active, and any prolonged interruption is a threat to an animal's survival. Thus it is of critical importance to maintain ventilation in the face of a variety of stimuli by adjusting the breathing pattern. Clark and von Euler (13) described the relationship between lung volume and breath timing in anesthetized cats. They demonstrated that inspiratory time (TI) depends on inspiratory volume and that the subsequent expiratory time (TE) depends on the preceding TI. A similar volume-timing relationship was found when a mechanical stimulus in the form of an external resistive load was applied. Loading of the inspiratory (57) or expiratory (33) phase caused a decrease in volume and an increase in the duration of the respective loaded breath phase. The response to the added loads was called the respiratory load compensation reflex. Load compensation is a sensory motor response.A sufficiently high load on the respiratory system results in the sensation of dyspnea, or breathlessness, which is one of the primary symptoms in pulmonary and cardiovascular diseases (40, 44). It is one of the main symptoms that limits patients with obstructive pulmonary diseases, and it can also be considered one of the most important factors in determining the severi...

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The effect of the resistance loading of inspiration and expiration on pulmonary stretch receptor discharge

Cited by 50 publications

References 14 publications

Comparisons among external resistive loading, drug-induced bronchospasm, and dense gas breathing in cats: Roles of vagal and spinal afferents

Comparisons among external resistive loading, drug-induced bronchospasm, and dense gas breathing in cats: Roles of vagal and spinal afferents

Alveolar Gas Pressure Changes with Resistive Loads in Man

Tracheal occlusion modulates the gene expression profile of the medial thalamus in anesthetized rats

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