Intravesical Ions, Osmolality and pH Influence the Volume Pressure Response in the Normal Rat Bladder, and This Is More Pronounced after DMSO Exposure

Abstract

The influence of intravesical ions, osmolality, pH value, and active transurothelial NaCl-transport inhibition (furosemide) on the rat bladder volume-pressure response was studied according to the concept of a permeable urothelium and according to direct effects of osmolality and K+ on in vitro muscle preparations. Bladder capacity was decreased by K+, hyperosmolality and pH 5, whereas it was increased by hypoosmolality, electrolyte-free media, furosemide and pH 8. The effects were pronounced after dimethyl sulfoxide (DMSO) exposure. Furosemide showed less effect. In diseased bladders with increased permeabiity, frequent voiding and painful urge sensations are due to an enhanced urine access to nerve and muscle cells of the detrusor. Frequent voiding reduces the urinary contact time within the bladder, thereby protecting from urine recirculation and from renal insufficiency. The bladder may not be exclusively under CNS control. As far as the present study is concerned, CO2, water, and normal saline do not seem to be appropriate urodynamic test media for providing the standard situation of bladder filling.