| Abstract: | To investigate the function of the bladder-urethra as a continuous unit we set up an in vitro whole bladder-urethra model (rabbit). We were able to measure the intravesical pressure at which saline infused into the bladder emptied via the urethra (“opening pressure”). Methoxamine added to the bath caused a significant increase in opening pressure, whereas phentolamine caused a significant decrease in opening pressure compared to controls. Atropine had no effect on opening pressure in the absence or presence of methoxamine. Thus, it appears that the in vitro bladder-urethra unit has intrinsic alpha-adrenergic tone that is of sufficient force to maintain an intravesical pressure of 7.0 cm H2O, and that this tone is not influenced by antagonism with the anticholinergic agent atropine. |
