Chronic exercise training improves ACh-induced vasorelaxation in pulmonary arteries of pigs

Lynelle R Johnson, Janet L. Parker, M. Harold Laughlin

Research output: Contribution to journalArticle

27 Scopus citations

Abstract

We hypothesized that exercise training would lead to enhanced endothelium-dependent vasodilation in porcine pulmonary arteries. Pulmonary artery rings (2- to 3-mm OD) were obtained from female Yucatan miniature swine with surgically induced coronary artery occlusion (ameroid occluder). Exercise training was performed for 16 wk, and vasomotor responses were studied by using standard isometric techniques. Contractile responses to 80 mM KCl, isosmotic KCl (10-100 mM), and norepinephrine (10-8 to 10-4 M) did not differ between sedentary (Sed) and exercise-trained (Ex) pigs. Relaxation was assessed to endothelium-dependent and endothelium-independent vasodilators after norepinephrine contraction. Pulmonary arteries of Ex pigs exhibited greater maximal relaxation to ACh (61.9 ± 3.5%) than did those of Sed pigs (52.3 ± 3.9%; P < 0.05). Endothelium-independent relaxation to sodium nitroprusside did not differ. Inhibition of nitric oxide synthase significantly decreased acetylcholine-induced relaxation, with greater inhibition in arteries from Ex pigs (P < 0.05). Inhibition of cyclooxygenase enhanced relaxation to acetylcholine in arteries from Sed pigs. We conclude that exercise training enhances endothelium-dependent (ACh-mediated) vasorelaxation in pulmonary arteries by mechanisms of increased reliance on nitric oxide and reduced production of a prostanoid constrictor.

Original languageEnglish (US)
Pages (from-to)443-451
Number of pages9
JournalJournal of Applied Physiology
Volume88
Issue number2
StatePublished - Feb 2000
Externally publishedYes

Keywords

  • Endothelium dependent
  • Nitric oxide synthase
  • Porcine
  • Prostanoids
  • Pulmonary circulation

ASJC Scopus subject areas

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

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