title: Ultrastructural identification of substance P cells and processes in the rat myenteric plexus.
abstract: Substance P containing perikarya and processes were identified by electron microscopic immunocytochemistry in the rat small intestine. The labelled perikarya possessed a cytoplasm of high electron density rich in organelles most of which contained numerous 80 to 130 nm large granulated vesicles. Labelled processes were found in pre- and postsynaptic positions. The presynaptic terminals contained 80 to 130 nm granular vesicles and 30 to 40 nm clear vesicles. These findings provide a morphological basis for the assumption that the peptide substance P may act as a transmitter and exerts postsynaptic effect on other intrinsic neurons and that the labelled cell bodies are links to a local neuronal circuit in the small intestine.
mesh_terms: D000818:Animals; D007124:Immunoenzyme Techniques; D008854:Microscopy, Electron; D009197:Myenteric Plexus / Q000033:anatomy & histology* / Q000378:metabolism; D009474:Neurons / Q000648:ultrastructure; D009940:Organoids / Q000648:ultrastructure; D051381:Rats; D011919:Rats, Inbred Strains; D013373:Substance P / Q000378:metabolism*; D013569:Synapses / Q000648:ultrastructure; D013572:Synaptic Vesicles / Q000648:ultrastructure
chemical_list: D013373:Substance P