Reflex prolongation of stage I of expiration

Remmers, John E.; Richter, Diethelm W.; Ballantyne, D.; Bainton, Cedric R.; Klein, John P.

doi:10.1007/bf00580675

Cited by 126 publications

(99 citation statements)

References 26 publications

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“…This pattern of response is consistent with the observations of Gilbey et al (1984). In their studies involving intracellular and extracellular recordings from the cardiac vagal motoneurones, they showed that the neurones did not fire during the ramp phase of phrenic nerve activity corresponding to inspiration, but were active during stage I expiration (post-inspiration) and during stage II expiration when the phrenic nerve was silent (Richter, 1982;Remmers, Richter, Ballantyne, Bainton & Klein, 1986). Maximum values of the membrane potential (-50 to -60 mV) during inspiration were followed by depolarization at the onset of stage I expiration when they discharged some action potentials.…”

Section: Of This Paper)supporting

confidence: 83%

Some reflex cardioinhibitory responses in the cat and their modulation by central inspiratory neuronal activity.

Daly

1991

The Journal of Physiology

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SUMMARY1. Cats were anaesthetized with a mixture of chloralose and urethane, and were artificially ventilated.2. An open pneumothorax was provided by two large-bore tubes which were sealed in the sixth intercostal space on each side. They were connected to a Fleisch pneumotachograph. Phasic changes in central inspiratory neuronal activity were measured quantitatively as changes in the volume of the pneumothorax during temporary interruption of artificial respiration, the volume of the lungs being held constant at their end-expiratory level. In this way the activity of slowly adapting pulmonary stretch receptors was maintained constant.3. Reflex cardioinhibitory responses were elicited by stimulation of (a) the carotid body chemoreceptors by intracarotid injections of cyanide; (b) the arterial baroreflex by controlled elevations of the blood pressure; (c) cardiac receptors by left atrial injections of veratridine; and (d) pulmonary C fibres (including J receptors) by right atrial injections of phenylbiguanide.4. The effects of central inspiratory neuronal activity on pulse interval were assessed by comparing the values observed during the inspiratory and expiratory phases of the respiratory cycle in the control state and during stimulation of each cardiovascular receptor group.5. The carotid chemoreceptor-induced bradycardia measured during the expiratory phase of respiration was reduced during inspiration to a value of about 15 % of control. The central inspiratory drive was less effective in altering the reflex responses from the arterial baroreceptors and cardiac receptors, the corresponding values being 42 and 51 % respectively.6. In contrast, the bradycardia evoked by pulmonary C fibre stimulation was not significantly affected by the central inspiratory drive.7. The differential nature of the modulation by the central inspiratory drive occurred independently of the integrity of the sympathetic nerve supply to the heart indicating that the cardiac efferents involved were largely fibres in the vagus nerves.8. The possible explanation of these results in terms of central mechanisms is discussed. MS 8872M. DE B. DALY

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Section: Of This Paper)supporting

confidence: 83%

Some reflex cardioinhibitory responses in the cat and their modulation by central inspiratory neuronal activity.

Daly

1991

The Journal of Physiology

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“…This hypothesis has been supported by data obtained from decerebrate cats. These data strongly support the concept of a two-phase theory of expiration (Richter, 1982; Remmers, Richter, Ballantyne, Bainton & Klein. 1986).…”

Section: Introductionsupporting

confidence: 70%

“…As has been reported by others (Gesell & Hamilton, 1941;Lawson, 1981Lawson, , 1982Remmers et al 1986), stimulation of the superior laryngeal nerve could result in prolongations of the expiratory phase. Two patterns of stimulation were used in this study.…”

Section: Prolongations Of Neural Expirationmentioning

confidence: 62%

“…While phase I has been defined by the depolarization of post-inspiratory medullary respiratory neurones, these depolarizations parallel those of vagal motoneurones innervating the thyroarytenoid, a laryngeal adductor muscle (see discussion i Remmers et al 1986). Thus, there is remarkable similarity between the changes in membrane potential of post-inspiratory neurones (e.g.…”

Section: Zl)jwlmentioning

confidence: 99%

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Differing control of neural activities during various portions of expiration in the cat.

John

Zhou

1989

The Journal of Physiology

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SUMMARY1. Activities of the phrenic nerve, intercostal nerve and nerves innervating the thyroarytenoid (TA) muscle of the larynx and triangularis sterni (TS) muscle of the chest wall were recorded in decerebrate, vagotomized, paralysed and ventilated cats.2. Neural inspiration was defined by the phase of phrenic activity. Neural expiration was divided into two phases with phase I corresponding to the duration of TA activity and phase II to TS activity; intercostal nerves discharged across both phases.3. Phrenic activity was terminated prematurely by electrical stimulation of the superior laryngeal nerve or of the dorsolateral region of the rostral pons. Following stimulation, neural activities during phase I of expiration rose and those during phase II fell in most animals.4. Stimulation of the superior laryngeal nerve during phase I caused augmentations of both TA and TS activity. At the termination of stimulation, a phase of TA discharge was recorded followed by a phase of TS activity. The durations of these post-stimulation phases of TA and TS activities approximated those of cycles without stimulation.5. Stimulation of the superior laryngeal nerve during phase II caused a resetting of neural expiration. Following stimulation, phases of TA and TS activity were recorded which had durations approximating those of cycles without stimulation.6. The current required to induce a premature onset of phrenic activity by stimulation of the dorsolateral region of the rostral pons fell dramatically with the change from phase I to phase II of expiration.7. We conclude that the control of neural activities differs markedly between phase I and phase II of expiration. The data support the hypothesis that postinspiratory medullary respiratory neurones play a fundamental role in the definition of the ventilatory cycle.

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“…Neurophysiologically expiration has been divided into early and late phases (24,36,(43)(44)(45)(46). The firing of geniohyoid I/E-MU during expiration did not appear to be strongly modulated by the two phases of expiration.…”

Section: Introductionmentioning

confidence: 97%

Motor unit regulation of mammalian pharyngeal dilator muscle activity.

Lunteren

1989

J. Clin. Invest.

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The present study examined the cellular regulation of one of the pharyngeal dilator muscles, the geniohyoid, by assessing its motor unit (MU) behavior in anesthetized cats. During spontaneous breathing, MU that (a) were active during inspiration only (I-MU) and (b) were active during both inspiration and expiration (I/E-MU) were identified. I-MU had a later inspiratory onset time and a shorter duration of inspiratory firing than did I/E-MU (P < 0.002 and P < 0.0001, respectively). I-MU were usually quiescent whereas I/E-MU were usually active during the last 20% of inspiration. I/E-MU fired more rapidly (P < 0.00001) and for relatively longer periods of time (P < 0.00001) during inspiration than during expiration. End-expiratory airway occlusion (preventing lung expansion during inspiration) augmented the inspiratory activity of both I-MU and I/E-MU. Conversely, end-expiratory airway occlusion reduced the absolute and relative firing durations (P < 0.002 and P < 0.00002, respectively) and the firing frequency (P < 0.001) of I/E-MU activity during expiration. These results indicate that (a) the complex pattern of pharyngeal dilator muscle activity is due to the integrated activity of a heterogeneous group of MU, (b) changes in the degree to which pharyngeal dilator muscles are active result from combinations of MU recruitment/decruitment and modulations of the frequency and duration of MU firing, and (c) gating of lung-volume afferent information occurs during the respiratory cycle.

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Reflex prolongation of stage I of expiration

Cited by 126 publications

References 26 publications

Some reflex cardioinhibitory responses in the cat and their modulation by central inspiratory neuronal activity.

Some reflex cardioinhibitory responses in the cat and their modulation by central inspiratory neuronal activity.

Differing control of neural activities during various portions of expiration in the cat.

Motor unit regulation of mammalian pharyngeal dilator muscle activity.

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