Changes of Contractility of the Vas Deferens to Field Stimulation in Diabetic Rats

Lee, Dong Hwan; Cho, Dae Haeng; Suh, Hong Jin; Yoon, Jai Young

Abstract

Diabetes is known to induce autonomic dysfunction and most experiments have been focused on the smooth muscle dysfunctions of the urinary bladder and corpus cavernosum in the genitourinary tract. The contractile response of the vas deferens is also decreased in diabetic rats and this effect may cause impairment of sperm transportation. However, few studies have been investigated the changes of contractility of the vas deferens in diabetic animals and little attention has been given to the differences between the contractilities of the prostatic and epididymal ends of the vas deferens in diabetic rats. In this study, the whole vas deferens was divided into two portions, prostatic and epididymal ends, and we examined the contractility of both segments to field stimulation at various frequencies from 4 to 64 Hz for 30 sec with pulses of 1 msec duration at 80 V in organ bath containing modified Tyrode's solution. Both initial twitch and the last contraction after 30 sec elicited by field stimulation were compared to clarify which component was more susceptible to field stimulation in control and diabetic rats. In the prostatic end, initial twitch was more impaired than the last contraction, which is believed that in diabetic rats, ATP(adenosine triphosphate) is more affected than NA(noradrenaline). In contrast, in the epididymal and the last contraction was more impaired than the initial twitch. In 64 Hz, initial twitch and the secondary contractions were not distinguished in the epididymal end of control rats, but in diabetic rats both phases were distinct. This means that the release of NA to field stimulation in the epididymal end is delayed in diabetic rats.