Fig. 4

Role of enteric submucosal neurons in serosal 100 nM trypsin-induced Cl⁻ secretion. Tetrodotoxin (TTX, 300 nM), 3-tropanyl-3,5-dichlorobenzoate (20 μM), SB-204070 (10 μM), atropine (10 μM), hexamethonium (10 μM), L-703,606 (10 μM) and pyrilamine (10 μM) were each added to the serosal side, and procaine (50 μM) was added either to the mucosal or serosal side 20 min before adding trypsin (100 nM) to the serosal side. The peak values for the increases in I _sc (ΔI _sc) induced by trypsin were determined, and are expressed as a percentage of the control response obtained in the adjacent tissue. Each data value is presented as the mean ± SE, with n = 3 for 3-tropanyl-3,5-dichlorobenzoate + SB-204070 (10 μM), n = 6 for mucosal procaine and pyrilamine, and n = 5 for the other compounds. *0.01 < P < 0.05, **0.001 < P < 0.01, and ***P < 0.001, compared with the control response by a paired t test