In vivo and in vitro beta 2-adrenergic receptor responsiveness in young and elderly asthmatics.
This pilot study was undertaken to characterize age-related alterations in airway and metabolic beta 2-adrenergic receptor response using terbutaline as a probe. A single dose of terbutaline 0.007 mg/kg was administered subcutaneously to 10 young (range 20-35 yrs) and 10 elderly (range 60-73 yrs) men and women with asthma. beta-Receptor function was assessed by serial pulmonary function tests, heart rate, blood pressure, plasma potassium, glucose, insulin, and catecholamine levels, and in vitro 3', 5'-cyclic adenosine monophosphate (cAMP) production of pure T lymphocytes. The trend was for lung beta 2-receptor response (bronchodilation) and T lymphocyte cAMP production to be lower in elderly than in young asthmatics, but differences did not reach statistical significance. Elderly subjects' beta 1-adrenergic receptor responsiveness (systolic blood pressure) was also dampened. These data suggest that T lymphocyte stimulation does reflect pulmonary beta 2-receptor response. Whether elderly asthmatics require and tolerate higher dosages of parenteral terbutaline than younger asthmatics deserves further study.
Hamelin
B A
BA
College of Pharmacy, University of Kentucky, Lexington 40536-0082.
Blouin
R A
RA
Wolf
K M
KM
Clifton
G D
GD
Chandler
M H
MH
D000328:Adult; D000367:Age Factors; D000368:Aged; D001249:Asthma / Q000503:physiopathology*; D001774:Blood Chemical Analysis; D001794:Blood Pressure / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*; D012129:Respiratory Function Tests; D013601:T-Lymphocytes / Q000187:drug effects*; D013726:Terbutaline / Q000008:administration & dosage / Q000494:pharmacology*
D011943:Receptors, Adrenergic, beta; D013726:Terbutaline