Experimental diabetes in the rat: alterations in the vesical function.

Vesical function has been studied in vivo in alloxan-diabetic rats. Rhythmic contractions evoked as a micturition reflex by a controlled distension of the bladder were recorded in urethane-anesthetized animals. These rhythmic contractions are essentially induced by the parasympathetic and inhibited by the sympathetic outflow. The study has been performed on male Sprague-Dawley rats. They were treated at the age of two months with vehicle (control group) or alloxan (100 mg/kg s.c.). Such treatment caused hyperglycemia (greater than 250 mg/dl) and glycosuria in most of the animals. In control animals, analyzed between 5 and 8 months of age, the contractions evoked by vesical distension appeared at a threshold volume between 0.5 and 1 ml, and they had a regular rate. In a first series of experiments, diabetic animals 3 months after treatment showed the evoked response at an average threshold volume of about 1.7 ml. while in animals with 6 months of experimental diabetes the average threshold volume was about 3.2 ml. The rate of contractions in diabetic animals became more and more irregular as the duration of diabetes increased. These marked functional alterations were associated with the evidence of bladder enlargement. In a second series of experiments, bovine brain gangliosides (10 mg/kg i.p./day) or saline were given to diabetic rats between the 30th and the 90th day after alloxan. Ganglioside administration significantly reduced bladder enlargement and the threshold volume for micturition reflex and improved the rate of bladder contractions. It is suggested that alterations of the autonomic nervous system can be expressed as functional vesical dysfunction in experimental diabetes.