Psychological stress and bladder function

Introduction and Hypothesis: Stress greatly influences the development of bladder symptoms,1 but the mechanisms involved are little understood. This study investigates the hypothesis that psychological stress in mice induces bladder dysfunction via altered contractile mechanisms.

Methods: Female mice were placed on a pedestal surrounded by water for 1 hour/day for 10 days, to induce water avoidance stress (WAS). Controls were not exposed to stress. 24‐hours after the final stress exposure, or following 10 days recovery, animals were euthanised, a blood sample taken for a corticosterone assay and whole bladders were isolated, catheterised and intravesical pressure recorded.

Results: Plasma corticosterone levels and voiding frequency were increased in the WAS group compared to controls (Figure 1). Bladders from stressed mice showed greater contractility in response to carbachol (P < 0.05) and to the purinergic agonist ATP (1 mM, P < 0.05) compared to controls. Voiding frequency was reduced following 10‐days stress‐free recovery (Figure 1B). This was accompanied by an increase in bladder compliance (Figure 1C), which had been unchanged during the stress protocol.

Conclusions: Repeated exposure to environmental stress produces a hormonal stress response and an overactive bladder phenotype. A stress‐free recovery period reduced voiding frequency, but this was due to compensation via increased bladder compliance, rather than a reversal of the stress‐induced changes.