Premium
Integrated autonomic control of bronchial blood flow and third generation airway dimensions during exercise
Author(s) -
White Saxon William,
McLeod Damian,
Quail Anthony,
Cottee David,
Pitsillides Koullis,
Seah Peng,
Parsons Gibbe,
McIlveen Stephen,
Gunther Robert
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.807.8
Subject(s) - sonomicrometry , zoology , chemistry , medicine , blood flow , treadmill , endocrinology , anesthesia , hemodynamics , biology
Neural mechanisms controlling 3 rd generation airway blood flow and dimensions were studied in 8 sheep trained to run on a treadmill during moderate exercise O 2 uptake 20 ml.kg −1 .min −1 for 2 min, 10 min recovery. We measured rapid changes in bronchial blood flow and conductance (Q br , C br ), circumference (Circ br ) and wall thickness (Th br ), using pulsed‐Doppler flowmetry, transit‐time sonomicrometry, and single crystal sonomicrometry, respectively. At exercise onset P a rose to 111% (P< 0.05) of resting and HR from 85 b/min to 164 b/min (P< 0.001) before returning in recovery at 5 min. Q br fell immediately to 91% and to 90% at 1.5 min (P< 0.05), and early in recovery to 84% (P< 0.05) before returning to pre‐exercise levels. C br followed a similar pattern (P< 0.05). Circ br fell immediately to 96% (P< 0.001) where it remained for the duration of exercise, and Th br increased and was sustained during exercise before returning to control levels in recovery. Cholinoceptor block by i.v. methscopolamine bromide modified these responses. P a rose to 109% of resting (P< 0.01), and HR rose from 120 b/min to 168 b/min (P< 0.001). A minor Q br and C br fall was not significant, and only an immediate transient fall in Circ br was evident (P< 0.01). Thus raised vagal activity dominates the exercise‐induced bronchovascular and airway wall constriction in 3 rd generation airways during and after exercise. Funding: Hunter Medical Research Institute