Fig. 5. Effects of Cl^– channel blockers on the HA response in X-organ neurons. (A,B) Superimposed current traces obtained after, during and before the superfusion of Cl^– channel blockers. Neither picrotoxin nor strychnine at 100 µmol l^–1 modified the HA-evoked current. (C) The cholinergic antagonist, d-tubocurarine (dTC; 20 µmol l^–1) blocked the HA-evoked current reversibly. (D) Average current–voltage curves (5 observations per point); solid circles, control conditions; open circles, blockage exerted by dTC. (E) Inhibition curve. Each point represents the average value for five observations. The solid line corresponds to a non-linear regression giving an adjusted IC₅₀=21±2 µmol l^–1.