Figure 2.

The use of herpes simplex virus (HSV) to treat interstitial cystitis. HSV gene transfer to the bladder and bladder afferent nerves of preproenkephalin (PPE), a precursor of enkephalin. HSV-PPE injected into the bladder wall will be taken up and transported up the afferent nerve that innervates the bladder. Because the HSV has a replication defect, there is no risk of clinical herpes infection. Enkephalin is released only in the nerve pathway that innervates the bladder to block pain by suppressing synaptic transmission via local spinal reflex or via the ascending central nervous system at the pontine micturition center (PMC) pathways.