CHOLINESTERASE ACTIVITY IN PIG AIRWAYS AND EPITHELIAL-CELLS

Acetylcholinesterase (AChE, EC 3.1.1.7) and butyrylcholinesterase (BCh E, EC 3.1.1.8) activities were detected in bronchial and bronchial epi thelial cell homogenates of the pig. In the bronchial homogenates, the maximal upstroke velocity (V-max) of AChE and the maximal velocity af ter second substrate fixation (V-ss) of BChE were 5.70 +/- 0.46 and 7. 87 +/- 0.81 mU/mg protein, respectively. In the epithelial cell homoge nates, a smaller amount of cholinesterase (ChE) was found: V-max was 0 .62 +/- 0.29 and V-ss, was 1.56 +/- 0.33 mU/mg protein for AChE and BC hE, respectively. AChE activity was increased by 21 +/- 58 in the bron chial homogenates and by 54 +/- 14% in the epithelial cell homogenates , when intact bronchial segments were incubated with a cyclooxygenase inhibitor, indomethacin (INDO). These results suggest that prostanoids may be involved in the regulation of AChE activity in pig airways.