Figure 4.

Optogenetic stimulation of ChR2+ bladder afferents revealed population-specific effects on bladder contractile activity. (A,B) Representative traces of ΔIVP in response to 1, 2 and 5 s light stimulation (blue bars) of peripheral bladder afferent terminals in Trpv1^Cre;Ai32 and Scn10a^Cre;Ai32 mice when bladders were drained prior to light stimulation (empty) and following saline distension to 80% of micturition threshold (MT; saline). (C,D) Graphs show the percentage of stimulation trials in Trpv1^Cre;Ai32 and Scn10a^Cre;Ai32 mice in which low amplitude (>1.0 but <7.5 mmHg) or high amplitude (≥7.5 mmHg) bladder contractions, or no change in intravesical pressure (IVP), were recorded in response to light stimulation during empty and saline conditions (*P < 0.05, Chi-square; n = 5 per group). (E) ΔIVP when the bladder was drained prior to light stimulation (empty) was dependent on stimulus duration (*P < 0.05) but not mouse line (P = 0.08), with a significant interaction (^#P < 0.05). There was also an effect of stimulus duration (*P < 0.05) when the bladder was pre-distended (saline), but no effect of mouse line (P > 0.05) and no interaction (P > 0.05). Two way ANOVAs with repeated measures, n = 5 per group.