Age-related changes in the response of the rat urinary bladder to neurotransmitters

The effect of age on the contractile response of the rat urinary bladder to various neurotransmitters was studied using in vitro detrusor strips isolated from female Wistar rats. The contractile responses to 8 neurotransmitters were determined for rat urinary bladders isolated from 3 age groups: 24, 16, and 6 months old. The results can be summarized as follows: 1) There was no age-dependent change in the maximum response to KCl. 2) The contractile response to norepinephrine, adenosine 5'-triphosphate (ATP), and serotonin increased with age. 3) The relaxation response to isoproterenol was significantly less in 24-month-old rats than in the other 2 age groups. 4) There were no age related changes in the responses to acetylcholine, prostaglandin F2 alpha, and angiotensin II. 5) Vasoactive intestinal polypeptide (VIP) failed to induce any response in the rat bladders of any group. 6) There were no significant differences in the ED50s for the 5 neurotransmitters among the 3 age groups. In summary, significant differences in the response to adrenergic, purinergic, and serotonergic stimulation were found as a function of age, whereas no age related changes in the response to cholinergic or generalized depolarization with KCl were found.