Pulmonary vascular α1-adrenoreceptor activity in conscious dogs after left lung autotransplantation

K. Nishiwaki, D. P. Nyhan, R. S. Stuart, P. M. Desai, W. P. Peterson, P. Rock, C. G. Pribble, P. A. Murray

Research output: Contribution to journalArticlepeer-review

Abstract

We investigated the extent to which sympathetic α1-adrenoreceptor activation is involved in chronic pulmonary vascular regulation in conscious dogs after left lung autotransplantation (LLA). Continuous left pulmonary vascular pressure-flow plots were generated in conscious dogs 3-4 wk post- LLA and in identically instrumented conscious dogs not subjected to LLA (sham-operated controls). LLA resulted in a marked upward shift in the baseline left pulmonary vascular pressure-flow relationship compared with the control group (P < 0.01), i.e., LLA caused a chronic increase in pulmonary vascular resistance. The sympathetic α1-adrenoreceptor antagonist prazosin partially reversed (P < 0.01) the LLA-induced increase in pulmonary vascular resistance. Circulating concentrations of norepinephrine and epinephrine at 2 and 4 wk post-LLA were not significantly different from values measured in control dogs. However, the dose-response relationship to the exogenous administration of the sympathetic α1-adrenoreceptor agonist phenylephrine was shifted (P < 0.05) to the left post-LLA compared with control, which indicates an increase in pulmonary vascular reactivity to α1- adrenoreceptor activation. This effect was not due to a generalized increase in pulmonary vascular reactivity to vasoconstrictor stimuli because the dose- response relationship to the thromboxane analogue U-46619 was not significantly altered post LLA compared with control. Thus LLA results in a chronic increase in pulmonary vascular resistance in conscious dogs. A component of the increase in pulmonary vascular resistance resulting from LLA is mediated by an enhanced reactivity to sympathetic α1-adrenoreceptor activation.

Original languageEnglish (US)
Pages (from-to)733-741
Number of pages9
JournalJournal of applied physiology
Volume74
Issue number2
StatePublished - 1993

Keywords

  • U- 46619
  • catecholamines
  • chronic instrumentation
  • epinephrine
  • hypertension
  • norepinephrine
  • phenylephrine
  • prazosin
  • pressure-flow plots
  • pulmonary circulation
  • sympathetic

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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