Blockade of the Proximal Pancreatic C Fiber Enhances Insulin Sensitivity in Rats

Numerous reports have been published on the putative mechanisms of development of insulin resistance in diabetes mellitus. However, no unified view has been established yet, especially in regard to involvement of the nervous system in the regulation of insulin sensitivity. In this study, we investigated the involvement of the autonomic nervous system in cellular glucose uptake by blocking Group C nerve fibers (C fibers) in the rat pancreas with capsaicin. When the junction of the proximal pancreatic duct and common bile duct was treated with capsaicin, glucose uptake was enhanced, probably due to increased insulin sensitivity. This suggests that capsaicin may partially block the vagal nerve fibers innervating the pancreas, resulting in enhanced insulin sensitivity. In other words, our finding suggests that pancreatic autonomic nerves may be involved in the regulation of insulin sensitivity and that partial blockade of these nerves may improve insulin sensitivity.