Effects of Beta-2 Adrenergic Agonists on Contracture of Airway Smooth Muscle Induced by Inhibition of Cholinesterase

摘要

The effect of beta-2 adrenoreceptor agonists on nerve agent-induced bronchoconstriction has been investigated in isolated canine trachealis and in human bronchi. Isoproterenol and salbutamol elicited relaxation of soman-induced contractures in canine tracheal smooth muscle. The relaxation was transitory. Return to the previous level of contracture occurred within 10 min. Human bronchi exposed to DFP developed large contractures similar to those seen in canine trachealis exposed to soman. Isoproterenol relaxed both the cholinergic and noncholinergic components of the contraction. Relaxation of DFP induced contractures in human bronchi by isoproterenol was also short lived. DFP-exposed human bronchi returned to the pre-isoproterenol level of tension within 10 min. Atropine produced sustained relaxation in both canine and human smooth muscle strips. Keywords: Cholinesterase inhibitor; Muscle relaxants. (AW)