title: Role of butyrylcholinesterase in canine tracheal smooth muscle function.
abstract: The role of butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE) in in regulating acetylcholine (ACh) lifetime was investigated by use of selective cholinesterase (ChE) inhibitors. Addition of 1 microM 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 microM iso-OMPA resulted in increases of 2-fold in the amplitude and 10-fold in the half-relaxation time of EFS-induced contractions. These alterations were accompanied by small but sustained baseline contractures that were antagonized completely by incubation with exogenous BuChE (2.5 U/ml). The results suggest that BuChE serves to coregulate the lifetime of ACh in canine tracheal smooth muscle.
authors.affiliation: Pathophysiology Division, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010-5425.
authors.forename: M
authors.initials: M
authors.lastname: Adler
authors.forename: M G
authors.initials: MG
authors.lastname: Filbert
mesh_terms: D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D002091:Butyrylcholinesterase / Q000502:physiology*; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D002802:Cholinesterases / Q000502:physiology*; D004285:Dogs; D006868:Hydrolysis; D007700:Kinetics; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D013379:Substrate Specificity; D014132:Trachea / Q000187:drug effects / Q000201:enzymology*
chemical_list: D002800:Cholinesterase Inhibitors; D002091:Butyrylcholinesterase; D002802:Cholinesterases; D000109:Acetylcholine