Fig E6.

Effect of tiotropium on capsaicin-induced contraction of guinea pig trachea. The tracheal tissue was inserted into 10-mL tissue baths with gassed Krebs-Henseleit solution kept at 37°C. The tissue was placed under 1 g of tension and left to settle for 1 hour, with the Krebs-Henseleit solution being replaced occasionally. The tissue was exposed to a supramaximal concentration of acetylcholine (1 mmol/L) and then washed; this was repeated twice more. The tissues were then incubated with vehicle or tiotropium for 30 minutes, after which cumulative response curves were measured to MCh (A) or capsaicin (B), and levels of tension in the tissue were recorded and expressed as a percentage of the average acetylcholine (ACh) response (n = 4).