Role of Butyrylcholinesterase in Canine Tracheal Smooth Muscle Function.

摘要

The role of butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE) in regulating acetylcholine (ACh) lifetime was investigated by use of selective cholinesterase (ChE) inhibitors. Addition of tetraisopropylpyrophosphoramide (iso-OMPA) led to a 98% inhibition of BuChE activity with little or no effect on AChE activity. This inhibition was accompanied by a 26% increase in the amplitude and a 43% prolongation in the half-relaxation time of contractions elicited by electric field stimulation (EFS). Coapplication of BW 284C51 (a selective AChE inhibitor) and 1 micromole iso-OMPA resulted in increases of 2-fold in the amplitude and 10-fold in the half-relaxation time of EFS-induced contractions. These alternations were accompanied by small but sustained baseline contractures that were antagonized completely by incubation with exogenous BuChE.