Endothelium-dependent relaxation differs in porcine pulmonary arteries from the left and right caudal lobes

Lynelle R Johnson, John R. Dodam, M. Harold Laughlin

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


We hypothesized that pulmonary arteries (PA) from identical branch orders within left and right caudal lung lobes would exhibit similar vasomotor responses. Arterial rings from caudal lung lobes of female swine were examined in vitro. Vascular smooth muscle contraction to KCl and norepinephrine did not differ. Vascular relaxation to endothelium-dependent (bradykinin, acetylcholine, A-23187) and -independent (sodium nitroprusside, zero-calcium Krebs solution) vasodilators was assessed. Right PA exhibited less maximal relaxation to acetylcholine (50%) than did left PA (69%; P < 0.001). Maximal relaxation to sodium nitroprusside did not differ, although right PA had a lower drug concentration resulting in half-maximal relaxation (6.26 x 10-8 M) than did left PA (9.57 x 10-8 M; P < 0.05). Nitric oxide synthase inhibition with an arginine analog (N(ω)-nitro-L-arginine methyl ester) depressed acetylcholine-induced relaxation but the left vs. right difference persisted. Indomethacin enhanced relaxation to acetylcholine and abolished the difference between left and right. We conclude that endothelium-dependent vasorelaxation is less in porcine fight than in left PA because of greater release of one or more constricting prostanoids in arteries from the right caudal lobe.

Original languageEnglish (US)
Pages (from-to)827-834
Number of pages8
JournalJournal of Applied Physiology
Issue number3
StatePublished - Mar 2000
Externally publishedYes


  • Arachidonic acid metabolites
  • Blood flow distribution
  • Endothelial cell function
  • Porcine
  • Pulmonary circulation

ASJC Scopus subject areas

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


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