Ultrastructural analysis of substance P-immunoreactive nerve fibers in myenteric ganglia of guinea pig small intestine

Abstract

Electron microscopic immunocytochemistry has been used to study the distribution and synaptic relationships of substance P (SP)-immunoreactive nerve fibers in ultrathin sections from whole-mount preparations of myenteric ganglia from guinea pig small intestine. At the light microscopic level, myenteric ganglia stained for ultrastructural study contained dense arrays of SP-immunoreactive nerve fibers around and between the neuronal and glial cell bodies. At the electron microscopic level, SP-containing nerve fiber profiles occurred throughout the neuropil of the myenteric ganglia. Both vesicle-containing and nonvesiculated nerve fiber profiles were immunoreactive. The positive vesiculated pro..