The Starling mechanism of the urinary bladder contractile function and the influence of hyperglycemia on diabetic rats

Abstract

Diabetic cystopathy is one of the common complications of diabetes. Bladder dysfunction in diabetes is attributable to diabetic neuropathy that induces sensory and autonomic nerve dysfunction. Materials and Methods In the present study, the contractile mechanism of the bladder was evaluated both with and without electrical stimulation in normal rats, streptozotocin (STZ)-induced diabetic rats, and diabetic rats with insulin treatment. Results Both the normal and diabetic rats had optimal capacity of bladder and optimal length of detrusor muscle strips. The peak values of the volume–pressure curves of the bladder and length–tension curves of detrusor muscle strips as well as the enhanced values after electrical stimulation in 6- and 10-week diabetic groups were lower than in the 6- and 10-week normal groups and insulin-treated groups. However, there was no significant difference in peak and enhanced values between normal rats and diabetic rats treated with insulin, indicating that voiding function was improved after insulin treatment. Conclusions The contractile function of rat's bladder including normal rats, diabetic rats, and diabetic rats treated with insulin is similar to the ‘Starling mechanism.’ It can be impaired by hyperglycemia, and insulin treatment is helpful to restore this function.