Autonomic nervous system pulmonary vasoregulation after hypoperfusion in conscious dogs

P. W. Clougherty, D. P. Nyhan, B. B. Chen, H. M. Goll, P. A. Murray

Research output: Contribution to journalArticlepeer-review

Abstract

We investigated the role of the autonomic nervous system (ANS) in the pulmonary vascular response to increasing cardiac index after a period of hypoperfusion (defined as reperfusion) in conscious dogs. Base-line and reperfusion pulmonary vascular pressure-cardiac index (P/Q̇) plots were generated by stepwise constriction and release, respectively, of an inferior vena caval occluder to vary Q̇. Surprisingly, after 10-15 min of hypoperfusion (Q̇ decreased from 139 ± 9 to 46 ± 3 ml·min-1·kg-1), the pulmonary vascular pressure gradient (pulmonary arterial pressure-pulmonary capillary wedge pressure) was unchanged over a broad range of Q̇ during reperfusion compared with base line when the ANS was intact. In contrast, pulmonary vasoconstriction was observed during reperfusion after combined sympathetic β-adrenergic and cholinergic receptor block, after β-block alone, but not after cholinergic block alone. The pulmonary vasoconstriction during reperfusion was entirely abolished by combined sympathetic α- and β-block. Although sympathetic α-block alone caused pulmonary vasodilation compared with the intact, base-line P/Q̇ relationship, no further vasodilation was observed during reperfusion. Thus the ANS actively regulates the pulmonary circulation during reperfusion in conscious dogs. With the ANS intact, sympathetic β-adrenergic vasodilation offsets α-adrenergic vasoconstriction and prevents pulmonary vasoconstriction during reperfusion.

Original languageEnglish (US)
Pages (from-to)23/5
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume254
Issue number5
StatePublished - 1988

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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