Influence of aging on the rat urinary bladder function.

We studied in vitro the change in bladder function with aging. The responses of muscle strips made from the rat bladder body to eight neurotransmitters and to four inorganic ions were examined. Six-month-old rats were used as controls and 16- and 24-month-old rats as aged rats. The results of this study are summarized as follows: (1) The contractile responses of the aged rat bladder to norepinephrine, adenosine triphosphate, and serotonin were significantly greater than those of young rat bladder. This may contribute to the development of an unstable bladder in elderly people. (2) In the aged rat bladder magnitude and speed of the response to calcium were significantly weaker which may account for the impaired detrusor contractility frequently observed in elderly persons. (3) There was no significant age-related difference in the response to other agents (acetylcholine, prostaglandin F2 alpha, angiotensin II, vasoactive intestinal polypeptide, KCl, BaCl2, and MgCl2).