This article reviews current knowledge on the mechanisms involved in t
he maturation of bronchial contractility in animal models and humans.
Extrapolation of animal data to humans is risky. Results of an in vitr
o study in human neonates are reported. beta(2)-adrenoceptor agonists
and cholinergic agents were effective in relieving early bronchospasm
in mechanically-ventilated premature infants. Controlled studies are n
eeded to determine whether these medications affect the subsequent occ
urrence of bronchial hyperreactivity in these patients.