Force development in muscle strips of the disused and nondistended rat urinary bladder

In rats the flow of urine was diverted from the bladder over a period of 7-10 days. Active length-tension curves of muscle strips of such disused bladders did not differ from those of controls, provided lengths were related to optimum length for force development. When, however, lengths were related to length in situ the active length-tension curves were shifted to the left. The muscle strips of the disused bladders showed a higher degree of stiffness than those of controls. The present findings are related to previous ones made on disused but distended bladders showing changes in the opposite direction. Taken together they demonstrate the importance of filling and periodic emptying for the preservation of normal length-tension relations in the bladder