Electrophysiological Investigation of Hydrostatic Pressure Mechanotransduction by Urothelial Cell Lines

The urothelium is the epithelial lining of the ureters, urinary bladder, and urethra. Recent discoveries have suggested that in addition to providing a barrier function to urine, the urothelium actively participates in sensory functions related to thermal, chemical, and mechanical stimuli, and releases chemical signals in response[1]. In addition to a sensitivity to cell membrane stretch caused by wall tension upon bladder filling, in vitro studies by our group have shown that urothelial cells may be sensitive to hydrostatic pressure directly without requiring membrane stretching [2]. Specifically, primary cultures of rat bladder urothelial cells exposed to 10 cmH₂O pressure on rigid substrates released significantly greater amounts of ATP compared to the baseline control without exposure to pressure. Moreover, this ATP response by rat urothelial cells to pressure was inhibited by pre-treatment of cells with ruthenium red, a non-specific antagonist of transient receptor potential (TRP) channels, suggesting a potential involvement of these channels in pressure mechanotransduction. Further understanding of the mechanisms, however, is needed to improve treatment of bladder dysfunction such as overactive bladder.