Ks. Lindeman et Ca. Hirshman, CORTICOSTEROID WITHDRAWAL RESTORES RESPONSES TO CALCIUM CHELATORS ANDENHANCES CHOLINERGIC RESPONSIVENESS, The American review of respiratory disease, 148(6), 1993, pp. 1581-1585
To investigate the importance of the inflammatory response in acute pe
ripheral airway constriction, we measured peripheral airway responses
to calcium chelators and acetylcholine in anesthetized Basenji-Greyhou
nd (BG) dogs before, during, and after chronic corticosteroid treatmen
t. A wedged bronchoscope technique was used to measure peripheral airw
ay resistance before and after aerosol challenge with 4% Na,EDTA or ac
etylcholine (10 mu g/ml) in contralateral lungs. After the initial mea
surements, five BG dogs received long-term treatment with methylpredni
solone (2 mg/kg/d, subcutaneously), and five dogs were not treated and
served as controls. Four weeks of methylprednisolone treatment almost
totally abolished responses to Na(2)EDTA, but responses to acetylchol
ine did not change significantly. After discontinuing corticosteroid t
herapy, responses to Na(2)EDTA returned to levels found before cortico
steroid treatment; responses to acetylcholine were significantly enhan
ced. We conclude that chronic corticosteroid treatment reduces acute r
esponse to calcium chelators and that withdrawal of corticosteroid the
rapy is associated with enhanced cholinergic responsiveness.