In vitro contractile responses of vasa deferentia from spontaneously diabetic BB rats

1. The effects of diabetes of 6 months' duration on autonomic function of the vas deferens were examined in spontaneously diabetic BB rats and diabetes-resistant BB rats. 2. Diabetes caused significant decreases in rat and testes weights, but had no effects on the weights of vasa deferentia compared to diabetes-resistant controls. 3. The contractile responses of vasa deferentia to nerve stimulation and to carbachol were increased compared to controls. However, the contractile responses of vasa deferentia from diabetic BB rats to ATP, phenylephrine, and 120 mM KCl were unaltered. 4. The increased responses to carbachol were associated with increases in the muscarinic receptor density, but no changes were detected in the number of dihydropyridine binding sites. 5. The data indicate that, in contrast to vasa deferentia from streptozotocin-diabetic rats which exhibit decreases in responsiveness to nerve stimulation and a non-specific supersensitivity to contractile agents, vasa deferentia from diabetic BB rats have no changes in sensitivity, and increased contractile responses to only nerve stimulation and carbachol. These differences in urogenital sensitivity to diabetes may be related to the insulin treatment which diabetic BB rats require to keep them alive.