Biomaterial Database

Pulmonary afferent control of breathing as end-expiratory lung volume decreases. 1990

J F Green, and M P Kaufman

Department of Human Physiology, School of Medicine, University of California, Davis 95616.

We studied reflex changes in breathing elicited by graded reductions in end-expiratory lung volume (EEVL) and the vagal nerves responsible. The chests of nine dogs anesthetized with alpha-chloralose were opened, and the lungs were ventilated by a phrenic nerve-driven servo-respirator. The immediate effects of a 50% reduction in end-expiratory transpulmonary pressure (EEPtp) from control (EEVL equivalent to functional residual capacity) were to significantly increase both tidal volume (VT) and breathing frequency (f) from 0.402 +/- 0.101 to 0.453 +/- 0.091 liter (mean +/- SD) and 11.8 +/- 5.4 to 15.7 +/- 6.4 breaths/min, respectively (P less than 0.05). Further reductions in EEPtp to 0 cmH2O did not change VT but augmented f to 19.6 +/- 6.6 breaths/min (P less than 0.05). The increase in f as EEVL decreased was due entirely to a reduction in expiratory time. Vagotomy abolished these reflexes. By 90 s after reduction in EEVL, arterial PCO2 fell significantly and VT returned to or below control values. We therefore repeated these experiments in five dogs whose blood gases were controlled by cardiopulmonary bypass. There were no secondary changes in VT and by 90 s breathing pattern could be characterized as rapid and deep. In another eight dogs submitted to the same collapse protocol, we recorded action potentials from all known categories of pulmonary vagal afferents. These studies demonstrated that the changes in breathing pattern induced by a 50% reduction in EEPtp were due to a withdrawal of slowly adapting stretch receptor activity; however, continued increases in f as EEVL was reduced further were due to increases in rapidly adapting stretch receptor activity.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D008168	Lung	Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.	Lungs
D008176	Lung Volume Measurements	Measurement of the amount of air that the lungs may contain at various points in the respiratory cycle.	Lung Capacities,Lung Volumes,Capacity, Lung,Lung Capacity,Lung Volume,Lung Volume Measurement,Measurement, Lung Volume,Volume, Lung
D008465	Mechanoreceptors	Cells specialized to transduce mechanical stimuli and relay that information centrally in the nervous system. Mechanoreceptor cells include the INNER EAR hair cells, which mediate hearing and balance, and the various somatosensory receptors, often with non-neural accessory structures.	Golgi Tendon Organ,Golgi Tendon Organs,Krause's End Bulb,Krause's End Bulbs,Mechanoreceptor,Mechanoreceptor Cell,Meissner's Corpuscle,Neurotendinous Spindle,Neurotendinous Spindles,Receptors, Stretch,Ruffini's Corpuscle,Ruffini's Corpuscles,Stretch Receptor,Stretch Receptors,Mechanoreceptor Cells,Bulb, Krause's End,Bulbs, Krause's End,Cell, Mechanoreceptor,Cells, Mechanoreceptor,Corpuscle, Meissner's,Corpuscle, Ruffini's,Corpuscles, Ruffini's,End Bulb, Krause's,End Bulbs, Krause's,Krause End Bulb,Krause End Bulbs,Krauses End Bulb,Krauses End Bulbs,Meissner Corpuscle,Meissners Corpuscle,Organ, Golgi Tendon,Organs, Golgi Tendon,Receptor, Stretch,Ruffini Corpuscle,Ruffini Corpuscles,Ruffinis Corpuscle,Ruffinis Corpuscles,Spindle, Neurotendinous,Spindles, Neurotendinous,Tendon Organ, Golgi,Tendon Organs, Golgi
D012018	Reflex	An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.
D004285	Dogs	The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)	Canis familiaris,Dog
D005652	Functional Residual Capacity	The volume of air remaining in the LUNGS at the end of a normal, quiet expiration. It is the sum of the RESIDUAL VOLUME and the EXPIRATORY RESERVE VOLUME. Common abbreviation is FRC.	Capacities, Functional Residual,Capacity, Functional Residual,Functional Residual Capacities,Residual Capacities, Functional,Residual Capacity, Functional
D000344	Afferent Pathways	Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.	Afferent Pathway,Pathway, Afferent,Pathways, Afferent
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001261	Pulmonary Atelectasis	Absence of air in the entire or part of a lung, such as an incompletely inflated neonate lung or a collapsed adult lung. Pulmonary atelectasis can be caused by airway obstruction, lung compression, fibrotic contraction, or other factors.	Atelectasis, Congestive,Lung Collapse,Atelectasis,Compression Atelectasis,Compression Pulmonary Atelectasis,Congestive Atelectasis,Congestive Pulmonary Atelectasis,Contraction Pulmonary Atelectasis,Postoperative Pulmonary Atelectasis,Resorption Atelectasis,Resorption Pulmonary Atelectasis,Atelectases,Atelectases, Compression,Atelectases, Compression Pulmonary,Atelectases, Congestive,Atelectases, Congestive Pulmonary,Atelectases, Contraction Pulmonary,Atelectases, Postoperative Pulmonary,Atelectases, Pulmonary,Atelectases, Resorption,Atelectases, Resorption Pulmonary,Atelectasis, Compression,Atelectasis, Compression Pulmonary,Atelectasis, Congestive Pulmonary,Atelectasis, Contraction Pulmonary,Atelectasis, Postoperative Pulmonary,Atelectasis, Pulmonary,Atelectasis, Resorption,Atelectasis, Resorption Pulmonary,Collapse, Lung,Compression Atelectases,Compression Pulmonary Atelectases,Congestive Atelectases,Congestive Pulmonary Atelectases,Contraction Pulmonary Atelectases,Postoperative Pulmonary Atelectases,Pulmonary Atelectases,Pulmonary Atelectases, Compression,Pulmonary Atelectases, Congestive,Pulmonary Atelectases, Contraction,Pulmonary Atelectases, Postoperative,Pulmonary Atelectases, Resorption,Pulmonary Atelectasis, Compression,Pulmonary Atelectasis, Congestive,Pulmonary Atelectasis, Contraction,Pulmonary Atelectasis, Postoperative,Pulmonary Atelectasis, Resorption,Resorption Atelectases,Resorption Pulmonary Atelectases
D015656	Respiratory Mechanics	The physical or mechanical action of the LUNGS; DIAPHRAGM; RIBS; and CHEST WALL during respiration. It includes airflow, lung volume, neural and reflex controls, mechanoreceptors, breathing patterns, etc.	Breathing Mechanics,Breathing Mechanic,Mechanic, Breathing,Mechanic, Respiratory,Mechanics, Breathing,Mechanics, Respiratory,Respiratory Mechanic