Separate origins for the dynorphin and enkephalin immunoreactive fibers in the inferior mesenteric ganglion of the guinea pig

Abstract

By different denervation procedures the origin of dynorphin‐(1–17) and enkephalin immunoreactive fibers in the guinea pig inferior mesenteric ganglion was investigated. It was found that the dynorphin‐(1–17)‐positive fibers reached the ganglion predominantly via the colonic nerves and to a lesser extent via the hypogastric and intermesenteric nerves whereas the enkephalin‐positive fibers reached the ganglion via the lumbar splanchnic nerves. These findings show that the dynorphin‐(1–17) and enkephalin systems are separate in this ganglion.