TRPV1 and chronic cystitis: The transient receptor potential (TRP) channel TRPV1 is upregulated in the bladders of patients with OAB and IC/PBS (Liu and Kuo, 2007), whilst both TRPV1 and TRPA1 have consistently been implicated in mediating normal and cystitis-induced mechanical sensitivity in rodents by modulating neuronal activation thresholds and enhancing bladder afferent responses to P2X receptor activation (Daly et al., 2007; Wang et al., 2008; DeBerry et al., 2014, 2015b; Yoshiyama et al., 2015; Grundy et al., 2018b).