Role of cysteinyl-leukotrienes and histamine in mediating intrinsic tone in isolated human bronchi

James L. Ellis, Bradley J. Undem

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78 Scopus citations


The intrinsic isometric tone of human isolated intralobar bronchi was evaluated in vitro. Human bronchi (inner diameter, 3 to 12 mm) were obtained from patients undergoing lung resection and from organ donors. The organ donor tissue was studied approximately 24 h after resection, during which time it was shipped to the laboratory in RPMI 1640 medium at 4° C. The bronchi obtained from patients with cancer was placed in the same medium and studied within 4 h of resection. All tissues were suspended in 10-ml organ baths containing oxygenated Krebs' solution at 37° C, at an initial load of 2 g. Tissues were washed every 15 min until they exhibited a stable tension (usually 60 min). Under these conditions the amount of active tension in the bronchi studied on the day of resection averaged 65 ± 9% of the maximal response to BaCl2 (30 mM), whereas after overnight incubation it averaged 31 ± 6%. Neither indomethacin nor atropine influenced the intrinsic tone in these tissues. By contrast, the LTD4 antagonists SKF 104353 and ICI 198615 and the histamine H-1 antagonists pyrilamine and chlorpheniramine effectively relaxed the bronchi. The 5' lipoxygenase inhibitor zileuton also produced a small fall in tension. Studies in which pyrilamine was combined with the leukotriene receptor antagonists indicated an additive effect. These results indicate that human bronchial smooth muscle exhibits a high degree of intrinsic tone, averaging more than 50% of available tone in fresh tissues studied in vitro under isometric conditions. The results suggest that this tone is due to the continual production and release of histamine and cysteinyl-leukotrienes.

Original languageEnglish (US)
Pages (from-to)118-122
Number of pages5
JournalAmerican journal of respiratory and critical care medicine
Issue number1
StatePublished - Jan 1994

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine


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