Related Experiment Videos
Non-adrenergic, non-cholinergic function in the human airway
T W Mackay1, G Hulks, N J Douglas
1Department of Medicine (RIE), University of Edinburgh, Royal Infirmary, U.K.
Respiratory Medicine
|August 6, 1998
Summary
Circadian variations in non-adrenergic, non-cholinergic (NANC) function impact airway calibre in mild asthma. Beta-adrenergic activity may inhibit NANC bronchodilation in healthy airways.
Area of Science:
- Respiratory Physiology
- Pulmonary Medicine
- Neuroimmunology
Background:
- Nocturnal asthma suggests altered non-adrenergic, non-cholinergic (NANC) function.
- Understanding NANC system's role in circadian airway variation is crucial for asthma management.
Purpose of the Study:
- To investigate the NANC system's role in circadian airway caliber changes in mild and nocturnal asthma.
- To explore the interaction between beta-adrenergic activity and NANC function in human airways.
Main Methods:
- Measured airway oscillatory resistance (Ros) after capsaicin inhalation in mild asthmatics, nocturnal asthmatics, and normal subjects at different times and with various blockade protocols.
- Utilized atropinic and beta-adrenergic blockade to isolate NANC pathway activity.
- Assessed changes in airway resistance (Ros) to quantify bronchodilation/constriction responses.
Main Results:
- Mild asthmatics exhibited circadian variation in airway resistance changes post-capsaicin, unlike nocturnal asthmatics.
- Normal subjects showed enhanced bronchodilation after combined atropine and propranolol blockade, indicating beta-adrenergic inhibition of NANC function.
- Nocturnal asthmatics did not display significant differences in capsaicin response between 0400 and 1600 hours.
Conclusions:
- Confirms circadian variation in NANC function in mild asthmatics.
- Suggests an interaction where beta-adrenergic activity inhibits NANC-mediated bronchodilation in normal human airways.
- Highlights potential NANC system dysregulation in nocturnal asthma pathophysiology.