Greater airway narrowing in immature than in mature rabbits during methacholine challenge

X. Shen, V. Bhargava, G. R. Wodicka, C. M. Doerschuk, S. J. Gunst, R. S. Tepper

Research output: Contribution to journalArticle

35 Scopus citations

Abstract

It has been demonstrated that methacholine (MCh) challenge produces a greater increase in lung resistance in immature than in mature rabbits (R. S. Tepper, X. Shen, E. Bakan, and S. J. Gunst. J. Appl. Physiol. 79: 1190- 1198, 1995). To determine whether this maturational difference in the response to MCh was primarily related to changes in airway resistance (Raw) or changes in tissue resistance, we assessed airway narrowing in 1-, 2-, and 6-mo-old rabbits during intravenous MCh challenge (0.01-5.0 mg/kg). Airway narrowing was determined from measurements of Raw in vivo and from morphometric measurements on lung sections obtained after rapidly freezing the lung after the MCh challenge. The fold increase in Raw was significantly greater for 1- and 2-mo-old animals than for 6-mo-old animals. Similarly, the degree of airway narrowing assessed morphometrically was significantly greater for 1- and 2-mo-old animals than for 6-mo-old animals. The fold increase in Raw was highly correlated with the degree of airway narrowing assessed morphometrically (r2 = 0.82, P < 0.001). We conclude that the maturational difference in the effect of MCh on lung resistance is primarily caused by greater airway narrowing in the immature rabbits.

Original languageEnglish (US)
Pages (from-to)2637-2643
Number of pages7
JournalJournal of Applied Physiology
Volume81
Issue number6
DOIs
StatePublished - Dec 1996

Keywords

  • airway morphometry
  • airway reactivity
  • maturation

ASJC Scopus subject areas

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

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