Journal of Applied Physiology, Vol 65, Issue 1 200-204, Copyright © 1988 by American Physiological Society
Relationships among airway reactivity, pupillary alpha-adrenergic and cholinergic responsiveness, and age
P. B. Davis and P. J. Byard
Department of Pediatrics, Case Western Reserve University School of Medicine, Rainbow Babies and Children's Hospital, Cleveland, Ohio 44106.
Healthy adult volunteers (n = 122), who denied personal history of lung
disease or family history of cystic fibrosis or asthma, took no interfering
medications, and had forced expiratory volume in 1 s greater than or equal
to 80% predicted, underwent methacholine challenge and pupillary reactivity
testing. Pupil diameter measured in dark and light test conditions declined
with age (Pearson's r = -0.54 and -0.36). Pupillary alpha-adrenergic
responsiveness (expressed as the concentration of phenylephrine required to
dilate the pupil 1 mm) was significantly correlated with age. Older
subjects required lower concentrations for dilation and therefore were more
sensitive to phenylephrine. Pupillary cholinergic responsiveness (the
concentration of carbachol required for 1-mm constriction) was not
significantly correlated with age. Therefore the significantly smaller
baseline pupil size in the elderly cannot be explained by failure of
alpha-adrenergic receptor responses or by increased pupillary cholinergic
responsiveness. We found no significant correlation of methacholine
bronchial reactivity with age. In addition, there was no relation between
airway reactivity and pupillary alpha-adrenergic or cholinergic
responsiveness in this sample of healthy adults. These findings, taken with
others in the literature, suggest that the contribution of alpha-adrenergic
and cholinergic responsiveness to nonspecific airway reactivity in healthy
persons is small, if it exists at all, and that there is no significant
change in airway reactivity with age in healthy adults.
