TRPV1 and overactive bladder: Nociceptin, a OP4 receptor agonist, modulates the micturition reflex by inhibiting the activity of TRPV1-expressing neurons at the periphery.[29] A study states that the intravesical infusion of nociceptin increases the urinary bladder capacity in patients with bladder overactivity, but not in normal subjects.[30] Thus, nociceptin and its derivatives may be clinically useful in UI.