Figure 5.

Interfering with the NO–cGMP pathway. A, B, Stimulus–response functions of mucosal receptors to mucosal stroking with calibrated von Frey hairs. The responses are before (●) and after (○) exposure to sildenafil (A) (○, 10 nm; ■, 30 nm; □, 100 nm) and ODQ (B) (○, 1 μm; ■, 3 μm; □, 10 μm). ***Significant difference from control curve using a two-way ANOVA (p < 0.001). C, Original recording of a mucosal receptor response to stroking with a 50 mg von Frey hair before (i) and after (ii, 10 nm; iii, 30 nm; iv, 100 nm) exposure to sildenafil.