Response of urinary sodium excretion to elevated intravesical pressure.

This experimental study was designed to investigate the possibility of an interaction between elevated intravesical pressure and urinary sodium excretion. Fourteen male New Zealand rabbits were used. After performing a ureterocutaneous diversion, urinary sodium excretion was measured in two situations: with the bladder empty and with the bladder overdistended and an intravesical pressure of 60 cm H2O. There was a significant decrease in urinary sodium excretion at an elevated intravesical pressure. The urinary sodium excretion returned to normal after relief of the pressure. The results suggest the existence of a neurogenic pathway activated by the elevated intravesical pressure.