Reflex cardiorespiratory responses to pulmonary vascular congestion

W. B. Wead, S. S. Cassidy, Richard J Coast, H. K. Hagler, R. C. Reynolds

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The purpose of these studies was to determine the reflex responses of the cardiovascular system and central inspiratory activity caused by pulmonary vascular congestion. We used a canine preparation in which the left lung was isolated in situ and could be exposed to a variety of stimuli, including distension of the pulmonary capillaries with blood, without direct mechanical or chemical alterations on the circulation. We found that lung expansion to 30 cmH2O and stimulation of nerve endings of the left lung with capsaicin caused pronounced transient reflex bradycardia (-30 to -50 beats/min) and hypotension (-25 to -40 mmHg) and caused reflex cessation of inspiratory activity. Pressurizing the left pulmonary vessels by injecting blood in volumes sufficient to raise pulmonary transcapillary pressures to 30 mmHg caused no changes in heart rate, systemic arterial pressure, or inspiratory muscle activity. These results lead us to conclude that pulmonary vascular congestion does not stimulate pulmonary C-fibers or any other nerve endings to such a degree as to cause detectable changes in blood pressure, heart rate, or central inspiratory activity. Morphometric analysis revealed distended capillaries engorged with blood, but the alveolar wall surface area was not increased which raises the possibility that expansion of the alveolar membrane may be needed to mechanically initiate the C-fiber reflex.

Original languageEnglish (US)
Pages (from-to)870-879
Number of pages10
JournalJournal of Applied Physiology
Volume62
Issue number3
StatePublished - 1987
Externally publishedYes

Fingerprint

Blood Vessels
Reflex
Lung
Unmyelinated Nerve Fibers
Nerve Endings
Heart Rate
Capsaicin
Bradycardia
Cardiovascular System
Blood Volume
Hypotension
Canidae
Arterial Pressure
Blood Pressure
Pressure
Muscles
Membranes

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Wead, W. B., Cassidy, S. S., Coast, R. J., Hagler, H. K., & Reynolds, R. C. (1987). Reflex cardiorespiratory responses to pulmonary vascular congestion. Journal of Applied Physiology, 62(3), 870-879.

Reflex cardiorespiratory responses to pulmonary vascular congestion. / Wead, W. B.; Cassidy, S. S.; Coast, Richard J; Hagler, H. K.; Reynolds, R. C.

In: Journal of Applied Physiology, Vol. 62, No. 3, 1987, p. 870-879.

Research output: Contribution to journalArticle

Wead, WB, Cassidy, SS, Coast, RJ, Hagler, HK & Reynolds, RC 1987, 'Reflex cardiorespiratory responses to pulmonary vascular congestion', Journal of Applied Physiology, vol. 62, no. 3, pp. 870-879.
Wead, W. B. ; Cassidy, S. S. ; Coast, Richard J ; Hagler, H. K. ; Reynolds, R. C. / Reflex cardiorespiratory responses to pulmonary vascular congestion. In: Journal of Applied Physiology. 1987 ; Vol. 62, No. 3. pp. 870-879.
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