title: Ontogeny of apelin and its receptor in the rodent gastrointestinal tract.
abstract: Apelin is the endogenous ligand for the APJ receptor and both apelin and APJ are expressed in the gastrointestinal (GI) tract. The aim of this study was to define ontogeny of apelin and APJ in the developing rodent GI tract by measuring expression levels and characterizing abundance and cellular localization at an embryonic stage (E18.5 or E21), two postnatal stages (P4, P16) and in the adult. Apelin and APJ mRNA levels were measured by real time RT-PCR, apelin and APJ-containing cells were identified by immunohistochemical (IHC) staining. Gastric, duodenal and colonic apelin and APJ mRNA levels were highest at birth and declined postnatally. In the postnatal rat stomach, few apelin peptide-containing cells were identified, the density of gastric apelin-containing cells increased progressively after weaning and into adulthood. A robust APJ immunostaining was observed postnatally in the epithelium, intestinal goblet cells and in smooth muscle cells. In the adult rat, APJ immunostaining in the surface epithelium and goblet cells decreased markedly. During the early postnatal period, in an apelin-deficient mouse, APJ expression and immunostaining in the gut were reduced suggesting that apelin regulates APJ. Together, our data support a role for the apelin-APJ system in the regulation of smooth muscle, epithelial and goblet cell function in the GI tract.
authors: Department of Surgery, University of Texas Medical Branch, 301 University Boulevard, Galveston, Texas 77555, USA.
authors: Guiyun
authors: G
authors: Wang
authors: Ramendra
authors: R
authors: Kundu
authors: Song
authors: S
authors: Han
authors: Xiang
authors: X
authors: Qi
authors: Ella W
authors: EW
authors: Englander
authors: Thomas
authors: T
authors: Quertermous
authors: George H
authors: GH
authors: Greeley
mesh_terms: D054392:Adipokines; D000818:Animals; D000073861:Apelin; D000075244:Apelin Receptors; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D041981:Gastrointestinal Tract / Q000378:metabolism*; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D051381:Rats; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D054392:Adipokines; D000073861:Apelin; D000075244:Apelin Receptors; C402826:Apln protein, mouse; C498579:Apln protein, rat; C491285:Aplnr protein, mouse; C491284:Aplnr protein, rat; D002352:Carrier Proteins; D036341:Intercellular Signaling Peptides and Proteins; D043562:Receptors, G-Protein-Coupled