Excitation and Inhibition of Phrenic Motoneurones by Inflation of the Lungs

Larrabee, Martin G.; Knowlton, G. C.

doi:10.1152/ajplegacy.1946.147.1.90

Cited by 116 publications

(31 citation statements)

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“…This 'all-or-none' effect during inspiration (Head, 1889;Hammouda & Wilson, 1932;Boyd & Maaske, 1939;Larrabee & Knowlton, 1946) was in striking contrast with the graded response to inflation applied during the expiratory phase (cf. also Larrabee & Hodes, 1948 The delay in the onset of the next inspiration by a steady inflation (Breuer, 1868) or by continuous electrical stimulation of the vagus nerves (see Wyss, 1964, also for further references) has often been used as an index of the inspiratory inhibition reflex (eg.…”

Section: Discussionmentioning

confidence: 79%

On the regulation of depth and rate of breathing

Clark¹,

Euler²

1972

The Journal of Physiology

656

284

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Section: Discussionmentioning

confidence: 79%

On the regulation of depth and rate of breathing

Clark¹,

Euler²

1972

The Journal of Physiology

656

284

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“…Similar patterns of diaphragmatic activity were recently reported during electrical stimulation of the pharyngeal wall (Takagi et al 1966), and in medullary inspiratory neurones at the beginning of swallowing (Sumi, 1963). It is possible that, after the primary inspiratory response of the aspiration reflex, some of the later bursts of activity in the phrenic-diaphragmatic units may be evoked or potentiated reflexly from the lungs by the mechanism underlying Head's paradoxical reflex (Head, 1889;Widdicombe, 1967); this may be the same as the inspiratory exciting reflex described by Larrabee & Knowlton (1946) and the respiratory augmenting reflex studied by Reynolds (1962). However, these latter reflexes are all elicited from lung receptors by large or rapid pulmonary inflations, while the aspiration reflex persists after vagotomy .…”

Section: Electroneurographic Analysis Of Respiratory Motoneuronesmentioning

confidence: 82%

Muscular, bronchomotor and cardiovascular reflexes elicited by mechanical stimulation of the respiratory tract

Tomori¹,

Widdicombe²

1969

The Journal of Physiology

331

118

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SUMMARY1. The effects of mechanical stimulation in the nose, epipharynx, laryngopharynx and tracheobronchial tree, and of chemical irritation of the nasal mucosa, were studied on various somatic and autonomic functions in cats.2. Action potentials were recorded from the diaphragm and rectus abdominis muscles of spontaneously breathing cats, and from the phrenic and lumbar nerves of paralysed, artificially ventilated cats. Expulsive processes such as sneezing and coughing evoked from the nasal, laryngopharyngeal and tracheobronchial mucosae were characterized by strong diaphragmatic and abdominal expiratory discharges; synchronous discharges in these antagonistic respiratory muscles and their motoneurones often occurred especially during laryngopharyngeal stimulation of coughing.3. The 'aspiration reflex' elicited from the epipharynx was characterized by brief bursts of high-frequency activity in the phrenic nerve and diaphragm, and was usually not followed by any expiratory activity in the rectus abdominis or its motoneurones. 4. In paralysed, artificially ventilated cats stimulation of the laryngeal and tracheobronchial regions caused large increases both in total lung resistance and in tracheal constrictor nerve fibre activity, indicating reflex tracheo-bronchoconstriction; similar stimulation of the epipharyngeal and nasal mucosae decreased both total lung resistance and tracheal constrictor nerve fibre activity, indicating reflex bronchodilation.5. In paralysed cats, stimulation of each of the four sites in the respiratory tract caused a reflex increase in systemic blood pressure, the largest hypertensive response coming from the epipharynx. Nervous activity in cervical sympathetic efferent fibres was increased by the stimulations, especially those of the epipharyngeal and laryngopharyngeal regions.

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“…With uncooled vagi, where clearly no frequency-dependent block of impulses can be present, this reflex is seen as a transient inspiratory effort in cats (Worzniak and Gesell, 1939;Larrabee and Knowlton, 1946;Widdicombe, 1954;Reynolds, 1962;Reynolds and Hilgeson, 1965], new born rabbits (Godfrey, 1966] and other mammalian species [Widdicombe, 1961]. It may underly the gasps induced in new-born babies by lung inflation [Cross et al, 1960;VOL.…”

Section: Resultsmentioning

confidence: 99%

Head's Paradoxical Reflex

Widdicombe

1967

Exp Physiol

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Cold block of the vagus nerves of rabbits completely prevents conduction in pulmonary stretch fibres at temperatures close to or higher than those required to block the Hering-Breuer inflation reflex. These temperatures are several degrees higher than those required to block Head's paradoxical reflex. It is concluded that Head's paradoxical reflex cannot be due to pulmonary stretch fibre activity during cold block; that is, cannot be due to cold block of the vagus nerves being more effective for high-frequency discharges (during lung inflation) than for low-frequency discharges in pulmonary stretch fibres. This conclusion is supported by a consideration of the pattern of Head's paradoxical reflex, and by a summary of the published evidence that the reflex can be elicited when the nerves are not being cooled at all.IN 1889, Head showed that, when conduction in the cervical vagus nerves of rabbits was partially blocked by cold, inflation of the lungs caused a strong and long-lasting inspiratory effort (usually referred to as Head's paradoxical reflex), instead of the inhibition of breathing seen when vagal conduction was intact (the Hering-Breuer inflation reflex). Paintal [1966] has recently shown that, during cold block of the cat's vagus nerves, low impulse frequency discharges in pulmonary stretch fibres pass the block more readily than do high frequency discharges, and he has concluded that this phenomenon underlies Head's paradoxical reflex; in other words, with cold block fewer impulses in pulmonary stretch fibres pass the block during the rapid discharges of lung inflation than do during the slower discharges of spontaneous breathing, and since the impulses inhibit inspiratory activity the effect of lung inflation during cold block is a lessening of inhibition or a stimulation of inspiration. Paintal concludes that Head's paradoxical reflex is a 'physiological artifact'.An important physiological role has been ascribed to Head's paradoxical reflex, both in causing the occasional deep breaths which are thought to counteract any tendency to atelectasis in quiet breathing Reynolds, 1962;Reynolds and Hilgeson, 1965;Widdicombe, 1964] and possibly in reinforcing the gasps or inspiratory efforts whereby new-born mamnmals aerate their lungs [Cross et al., 1960; Cross, 1961]; it therefore seems worthwhile to describe experiments, hitherto only briefly reported [Widdicombe, 1959], which indicate that Head's paradoxical reflex is not a 'physiological artifact', and to emphasize some of the welldocumented evidence for the same conclusion (see Discussion). * Present address.

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Excitation and Inhibition of Phrenic Motoneurones by Inflation of the Lungs

Cited by 116 publications

References 0 publications

On the regulation of depth and rate of breathing

On the regulation of depth and rate of breathing

Muscular, bronchomotor and cardiovascular reflexes elicited by mechanical stimulation of the respiratory tract

Head's Paradoxical Reflex

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