Figure 7.

Chloride‐dependence of the I _sc response evoked by propionylcholine (500 μM at the serosal side, A) or butyrylcholine (500 μM at the serosal side, B) across colonic mucosal preparations. For each experimental series the response to propionylcholine or butyrylcholine was tested after chloride substitution by gluconate (on the mucosal and serosal side; ‐Chloride) or in the presence of bumetanide (100 μM at the serosal side), respectively, and compared with the response under control conditions (open bars). Values are given as increase in I _sc (ΔI _sc) above baseline just before administration of the respective choline ester and are means ± SEM; n = 6 for all series except the control response to the bumetanide series for propionylcholine (n = 5) or the series with butyrylcholine in the presence of bumetanide (n = 7). * P < 0.05 versus response evoked by propionylcholine or butyrylcholine in the respective control series.