Fig 2.

Effect of muscarinic antagonists on depolarization of isolated guinea pig vagus nerve. A and B, Concentration response data testing tiotropium and ipratropium against capsaicin (1 μmol/L)–induced depolarization. C, Effect of tiotropium (1 nmol/L) against a range of TRPV1 agonists (capsaicin, 1 μmol/L; RTX, 3 nmol/L PGE₂, 10 μmol/L). D, Glycopyrrolate (10 nmol/L) and atropine (1 μmol/L) were tested against capsaicin responses. E and F, Tiotropium (1 nmol/L) and ipratropium (10 nmol/L) were profiled against acrolein (TRPA1 agonist, 300 μmol/L)–induced depolarization, with HC-030031 (TRPA1 antagonist, 10 μmol/L) as a positive control (Fig 2, E), and tiotropium was also profiled against GSK1016790a (TRPV4 agonist, 300 nmol/L)–induced depolarization, with HC-067047 (TRPV4 antagonist, 10 μmol/L) as a positive control (Fig 2, F). Data are shown as means ± SEMs of the percentage inhibition of tussive agent–induced depolarization (n = 4-6).