title: Sympathetic innervation of human mesenteric artery and vein.
abstract: BACKGROUND
  Innervation of blood vessels shows inter-species variability. There are few studies on the innervation of human vessels; thus, healthy mesenteric vessels were studied to identify the expression of immunomarkers and the morphology of sympathetic innervation as the basis for a study of mesenteric vessels in inflammatory bowel disease.
  
  
  RESULTS
  Electron microscopy studies examined the relationships of nerves to smooth muscle cells. In veins, nerves were distributed throughout the medial smooth muscle coat, often in close apposition (50 nm) to smooth muscle cells. In arteries, nerves were located at the adventitial-medial border, few closer than 2,000 nm to smooth muscle cells, often with interposing connective tissue and Schwann cell processes. There was a significantly greater nerve density in veins than in arteries (227 vs. 41 mm(2); p = 0.03). Immunohistochemical studies revealed the presence of sympathetic and sensory-motor nerves in arteries and veins.
  
  
  CONCLUSIONS
  It is suggested that in humans with an upright stance, the mesenteric venous system plays a particularly important role in controlling mesenteric capacitance, which is reflected by their dense innervation. It is speculated that transmitters released from perivascular nerves supplying the human mesenteric arteries may play a long-term (trophic) role in addition to short-term signalling roles.
authors.affiliation: Autonomic Neuroscience Centre, Department of Surgery, Royal Free and University College Medical School, London, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Birch
authors.forename: Mark
authors.initials: M
authors.lastname: Turmaine
authors.forename: Paul B
authors.initials: PB
authors.lastname: Boulos
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Burnstock
mesh_terms: D006801:Humans; D007150:Immunohistochemistry; D008638:Mesenteric Arteries / Q000166:cytology / Q000294:innervation*; D008642:Mesenteric Veins / Q000166:cytology / Q000294:innervation*; D008854:Microscopy, Electron; D009131:Muscle, Smooth, Vascular / Q000294:innervation; D032389:Myocytes, Smooth Muscle / Q000166:cytology; D013564:Sympathetic Nervous System / Q000033:anatomy & histology*