Vasomotor reactions in the islets affecting the blood glucose levels.

1. The spiral nerve fiber and the nerve ganglion are demonstrated adjacent to the small pancreatic duct, artery and vein of the mouse in vivo. 2. Epinephrine and ephedrine, which are sympathomimetic amines, cause vasoconstriction of the afferent and efferent vessels of the islets of Langerhans and cause the interruption of circulation in the intrainsular capillary plexuses, which results in increased blood glucose levels. 3. Methacholine chloride, a parasympathomimetic drug, causes vasodilatation of the afferent and efferent vessels of the islets along with slower but continuous blood flow in the intrainsular capillary plexus, thus causes decreased blood glucose levels. 4. These changes in microcirculation of the islets of Langerhans in mice prove that one of the mechanisms of glucose homeostasis is mediated through autonomic nervous system by alteration of the vascular supply of the islets, which may be classified as neurovascular homeostatic regulator.