OPRL1 and interstitial cystitis: Anand found that OPRL1-positive nerve fibre content in the urothelium of the bladder was significantly increased in patients with hyperactivity and bladder pain syndrome, and capsaicin responses of rat dorsal root ganglion (DRG) neurons in the presence of N/OFQ were dose-dependently inhibited, indicating that activating OPRL1 represents a potential clinical pain management strategy54.