Reduced visceromotor response to bladder distension in mGluR5 knockout mice compared to wild type littermates. A. Representative VMR tracings from a WT and mGluR5 KO mice. As the intravesicular pressure is increased (20-80 mmHg), the EMG activity of the abdominal muscle (VMR) is also increased. The total amount of activity (area under the curve) during the 20 second distention is calculated to determine the evoked response at each pressure. B. mGluR5 KO (n = 18) mice have a significantly blunted VMR when compared to WT littermates (n = 15) +/- SEM,* p < 0.05, **p < 0.01, ***p < 0.001. 2-way ANOVA with Bonferroni post-hoc test. There were no obvious histological differences observed between mGluR5 KO mice (1D) and their WT littermates (1C). In both, the urothelium (above dashed line) has normal layers of superficial facet cells (arrows), intermediate cells (black arrowhead) and basal cells (white arrowhead).