A Model for the Contribution of Lung Receptors to the Control of Breathing: Positive and Negative Feed-Backs
Experiments in dogs in which pulmonary and systemic circulations were controlled separately have shown that minute ventilation (̇VE) increased when the CO2 content of pulmonary arterial blood was increased, while systemic arterial PCO2 was kept constant. Similarly, ̇VE also increased when pulmonary blood flow was increased at constant PCO2. These responses were abolished after bilateral vagal transection10, 20. We present two positive feed-backs which may account for the increases in ̇VE observed in these experiments. Further, a negative feed-back is presented controlling the CO2 related off-switch of inspiration.
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- 10.Green, F.G. and M.I. Sheldon, Ventilatory changes associated with changes in pulmonary blood flow in dogs. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 54: 997–1002 (1983).Google Scholar
- 11.Grinten, C.P.M. van der, W.R. de Vries, S.C.M. Luijendijk, Vagal modification of inspiratory activity during pressure breathing in cats. Europ. Respir. J. 2 Suppl 5: 311S (1989).Google Scholar
- 13.Grinten C.P.M. van der, E. Schoute, W.R. de Vries, S.C.M. Luijendijk, Conventional versus slug CO2 loading and the control of breathing in anaesthetized cats. J. Physiology 445: 487–498 (1992).Google Scholar
- 15.Hering, E., Die Selbststeuerung der Athmung durch den Nervus vagus. Sitzungsber. Akad. Wiss. Wien 57: 672–677 (1868).Google Scholar
- 16.Luijendijk, S.C.M., Within-breath PCO2 levels in the airways and at the pulmonary stretch receptor sites. J. Appl. Physiol.: Respirat., Environ. Exercise Physiol. 55: 1333–1340 (1983).Google Scholar
- 19.Pack, A.I., R.G. DeLaney and A.P. Fishman, Augmentation of phrenic neural activity by increased rates of lung inflation. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 50: 149–161 (1981).Google Scholar
- 20.Sheldon M.I. and F.G. Green, Evidence for pulmonary CO2 chemosensitivity: effects on ventilation. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 52: 1192–1197 (1982).Google Scholar