STRESS-INDUCED BLADDER MAST-CELL ACTIVATION - IMPLICATIONS FOR INTERSTITIAL CYSTITIS

Purpose: To investigate whether acute psychological stress may activat e bladder mast cells which appear to play a significant role in the pa thophysiology of interstitial cystitis, a syndrome that occurs primari ly in females and is characterized by urinary urgency, frequency and s uprapubic pain, all of which often worsen with stress. Materials and M ethods: Non-traumatic immobilization stress was used as a model of acu te emotional stress by placing a rat in a plexiglass immobilizer, afte r first bringing each rat in the laboratory daily for 4 days to reduce the stress of handling. The rat was then anesthetized, decapitated an d the bladder removed and fixed for light and electron microscopy. Res ults: This type of stress resulted in activation of over 70% of bladde r mast cells within 30 minutes, as evidenced by light and electron mic roscopy. Pretreatment of the animals with intraperitoneal administrati on of polyclonal antiserum to corticotropin releasing hormone had no e ffect on bladder mast cell activation and no nerve fibers positive for this hormone were identified in the bladder. Stress-induced bladder m ast cell activation was, however, substantially reduced in animals tre ated neonatally with capsaicin suggesting that sensory neuropeptides, such as substance P, of which increased positive nerve fibers have bee n localized close to bladder mast cells, are involved in this response . Conclusions: This is the first time that psychological stress is sho wn to activate bladder mast cells, apparently via the action of at lea st some sensory neuropeptides. These findings have implications for th e pathophysiology and possible therapy of interstitial cystitis.