title: Ultrastructural localisation of substance P, vasoactive intestinal peptide and somatostatin immunoreactivities in the submucous plexus of guinea pig ileum.
abstract: The submucous neurons, especially those related to the lymphatic vessels, together with their associated synapses, were studied ultrastructurally with respect to their immunoreactivities for 3 types of neuropeptides, namely substance P (SP), vasoactive intestinal peptide (VIP) and somatostatin (SOM). With the antibodies directed against the 3 types of neuropeptides, a variable number of submucous neurons including those contacting the lymphatic vessels were immunostained. Based on the immunoreactivities and synaptic relations with the submucous neurons contacting the lymphatic vessels, at least 4 types of synaptic relations with the submucous neurons contacting the lymphatic vessels, at least 4 types of synaptic configurations were observed: immunopositive terminals with positive neurons, immunopositive terminals with negative neurons, immunonegative terminals with positive neurons and immunonegative terminals with negative neurons. All 4 types of synaptic configurations were observed in SP and VIP-immunostained specimens, with the exception of type 3 which was not encountered in samples immunoreacted for SOM. When the proportions of all 4 types of peptidergic immunopositive terminals contacting the lymphatic vessel-associated neurons were totalled, the value exceeded 100%, suggesting the coexistence of 2 or more neuropeptides in the same terminals. Furthermore, some immunoreactive axon terminals made direct synaptic contacts with positive neurons suggesting the formation of the so-called 'peptide neuron chain'. It is speculated from this study that the submucous neurons receive multiple peptidergic inputs. The various synaptic contacts would imply a complicated reflex pathway in the submucous plexus.
authors.affiliation: Department of Anatomy, National University of Singapore.
authors.forename: X Y
authors.initials: XY
authors.lastname: Wang
authors.forename: W C
authors.initials: WC
authors.lastname: Wong
authors.forename: E A
authors.initials: EA
authors.lastname: Ling
mesh_terms: D000818:Animals; D006168:Guinea Pigs / Q000033:anatomy & histology / Q000378:metabolism*; D007082:Ileum / Q000294:innervation*; D007124:Immunoenzyme Techniques; D008297:Male; D008854:Microscopy, Electron; D009479:Neuropeptides / Q000032:analysis* / Q000276:immunology; D017729:Presynaptic Terminals / Q000737:chemistry / Q000648:ultrastructure; D013004:Somatostatin / Q000032:analysis; D013368:Submucous Plexus / Q000737:chemistry* / Q000648:ultrastructure*; D013373:Substance P / Q000032:analysis; D014660:Vasoactive Intestinal Peptide / Q000032:analysis
chemical_list: D009479:Neuropeptides; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D013004:Somatostatin