The effect of urine volume and nitric oxide on basal bladder blood flow: Response to catheterization and drainage

Preliminary studies demonstrated that catheterization and drainage of the u rinary bladder resulted in a significant increase in blood flow to the blad der. The objectives of this study were to determine 1) the relationship bet ween urine volume and basal blood flow to the bladder smooth muscle and muc osa, 2) the effect of acute catheterization and drainage on bladder mucosal and smooth muscle blood now, and 3) whether nitric oxide was involved in r egulation of basal blood now or the increase in blood flow observed after c atheterization and bladder drainage. Twenty-four rabbits were separated int o two groups: group 1 (14 rabbits) and group 2 (10 rabbits) treated with L- NAME (NOS inhibitor) 30 minutes before blood now measurement. Blood flow wa s measured in all animals using a fluorescent microsphere technique before and immediately after catheterization and drainage of the bladder. The resu lts demonstrated that 1) blood flow to the muscle and mucosa were independe nt of urine volume at the time of catheterization and drainage; 2) catheter ization and drainage significantly increased blood now to both the bladder smooth muscle and bladder mucosa, but not to the kidney; 3) L-NAME signific antly reduced basal blood now to the kidney, but not to the bladder smooth muscle or mucosa: and 4) L-NAME completely prevented the catheterization- a nd drainage-induced increases in blood flow to the bladder body mucosa and muscle. This study demonstrates that basal blood flow to the bladder smooth muscle and mucose during filling is independent of NO control: although bl adder blood flow may be increased significantly by NO synthesis and release during bladder emptying, and thus may be an important regulator of blood f low during and immediately Following micturition. Neurourol. Urodynam. 20:1 15-124, 2001. (C) Wiley-Liss, Inc.