Degradation of acetylcholine in human airways: role of butyrylcholinesterase.
1. Neostigmine and BW284C51 induced concentration-dependent contractions in human isolated bronchial preparations whereas tetraisopropylpyrophosphoramide (iso-OMPA) was inactive on airway resting tone. 2. Neostigmine (0.1 microM) or iso-OMPA (100 microM) increased acetylcholine sensitivity in human isolated bronchial preparations but did not alter methacholine or carbachol concentration-effect curves. 3. In the presence of iso-OMPA (10 microM) the bronchial rings were more sensitive to neostigmine. The pD2 values were, control: 6.05 +/- 0.15 and treated: 6.91 +/- 0.14. 4. Neostigmine or iso-OMPA retarded the degradation of acetylcholine when this substrate was exogenously added to human isolated airways. A marked reduction of acetylcholine degradation was observed in the presence of both inhibitors. Exogenous butyrylcholine degradation was prevented by iso-OMPA (10 microM) but not by neostigmine (0.1 microM). 5. These results suggest the presence of butyrylcholinesterase activity in human bronchial muscle and this enzyme may co-regulate the degradation of acetylcholine in this tissue.
Norel
X
X
CNRS URA 1159, Centre Chirurgical Marie-Lannelongue, France.
Angrisani
M
M
Labat
C
C
Gorenne
I
I
Dulmet
E
E
Rossi
F
F
Brink
C
C
D000109:Acetylcholine / Q000378:metabolism*; D000110:Acetylcholinesterase / Q000378:metabolism; D002093:Benzenaminium, 4,4'-(3-oxo-1,5-pentanediyl)bis(N,N-dimethyl-N-2-propenyl-), Dibromide / Q000494:pharmacology; D001980:Bronchi / Q000201:enzymology / Q000378:metabolism; D002091:Butyrylcholinesterase / Q000378:metabolism*; D002794:Choline / Q000378:metabolism; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D002801:Cholinesterase Reactivators / Q000494:pharmacology; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D009388:Neostigmine / Q000494:pharmacology; D012137:Respiratory System / Q000201:enzymology*; D013770:Tetraisopropylpyrophosphamide / Q000494:pharmacology
D002800:Cholinesterase Inhibitors; D002801:Cholinesterase Reactivators; D009388:Neostigmine; D002093:Benzenaminium, 4,4'-(3-oxo-1,5-pentanediyl)bis(N,N-dimethyl-N-2-propenyl-), Dibromide; D013770:Tetraisopropylpyrophosphamide; D000110:Acetylcholinesterase; D002091:Butyrylcholinesterase; D002794:Choline; D000109:Acetylcholine