title: Immunohistochemical demonstration of peptidergic nerve fibers associated with the central lacteal lymphatics in the duodenal villi of dogs.
abstract: Immunohistochemical demonstration was made of the peptidergic nerves distributed in the central lacteal lymphatics of the canine duodenal villi. The central lacteal-associating nerve fibers were predominantly immunoreactive for both substance P (SP) and calcitonin gene-related peptide (CGRP). Observation of doubly immunostained sections evidenced that both peptides were located in one and the same nerve fibers. The SP/CGRP-immunoreactive fibers were concentrated in the intermediate portion of the villus height. Ultrastructurally, the SP/CGRP-immunoreactive nerve fibers ran closely beneath the endothelial cells of the lacteal, some of them penetrating into the cytoplasm with knob-like swellings. The immunoreactive products were localized to large-cored vesicles in the sub- and intra-endothelial nerves. The occurrence of SP and CGRP in the nerve fibers distributed in the central lacteals which lack smooth muscles implies that these nerves may be sensory in nature. A mechanoreceptive function of the nerves is proposed on the basis of their peculiar knob-like projection into the lacteal endothelium.
authors.affiliation: Department of Anatomy, Tokyo Medical College, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Ichikawa
authors.forename: M
authors.initials: M
authors.lastname: Shiozawa
authors.forename: T
authors.initials: T
authors.lastname: Iwanaga
authors.forename: S
authors.initials: S
authors.lastname: Uchino
mesh_terms: D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis*; D004285:Dogs; D004386:Duodenum / Q000737:chemistry / Q000294:innervation*; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives / Q000032:analysis; D019004:Galanin; D019886:Gastrin-Releasing Peptide; D007150:Immunohistochemistry; D008208:Lymphatic System / Q000737:chemistry / Q000294:innervation*; D016253:Microscopy, Immunoelectron; D009412:Nerve Fibers / Q000737:chemistry; D009478:Neuropeptide Y / Q000032:analysis; D010455:Peptides / Q000032:analysis; D013373:Substance P / Q000032:analysis*; D014660:Vasoactive Intestinal Peptide / Q000032:analysis*
chemical_list: D009478:Neuropeptide Y; D010455:Peptides; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D004744:Enkephalin, Methionine; D019886:Gastrin-Releasing Peptide; C033453:enkephalin-Met, Arg(6)-Gly(7)-Leu(8)-; D019004:Galanin; D015740:Calcitonin Gene-Related Peptide