title: The importance of EDHF in endothelium-dependent relaxation increases distally in mesenteric arteries depending upon the contracting agent.
abstract: OBJECTIVE
  The importance of endothelium-derived hyperpolarizing factor (EDHF) in endothelium-dependent relaxation (EDR) is influenced by multiple factors, including vascular territory and caliber, pre-existing tone and its determining factors.
  
  
  METHODS
  Using isometric myography we noticed that in rat mesenteric resistance arteries (RMA2; 2nd order branches) EDHF-mediated relaxation is increased when precontraction is induced by prostaglandin F2 (PGF) compared to phenylephrine (PHE) and we investigated the participation of certain K channels. Here we extend the study on more proximal vascular fragments; from mesenteric arcade and from 1st order branches.
  
  
  RESULTS
  The EDHF component of EDR is stronger distally only when precontraction is induced by PHE. Moreover, morphometric analysis shows a strong inverse correlation between the magnitude of EDHF response and arterial caliber.
  
  
  CONCLUSIONS
  Other authors have shown that EDHF increases in relative importance distally, but we show that this change in EDR profile depends upon the contracting agent used, with implications regarding the physiological relevance of accumulated data refering to EDHF and nitric oxide as mediators of EDR in resistance arteries.
authors.affiliation: Department of Physiology, "Gr. T. Popa" University of Medicine and Pharmacy, Iaşi, Romania.
authors.forename: Loredana
authors.initials: L
authors.lastname: Hurjui
authors.forename: Ionela Lăcrămioara
authors.initials: IL
authors.lastname: Serban
authors.forename: Cristina
authors.initials: C
authors.lastname: Oprişa
authors.forename: Elena Simona
authors.initials: ES
authors.lastname: Tucaliuc
authors.forename: M M
authors.initials: MM
authors.lastname: Hogaş
authors.forename: D
authors.initials: D
authors.lastname: Tucaliuc
authors.forename: I
authors.initials: I
authors.lastname: Hurjui
authors.forename: Veronica
authors.initials: V
authors.lastname: Luca
authors.forename: D N
authors.initials: DN
authors.lastname: Serban
mesh_terms: D000818:Animals; D001685:Biological Factors / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000187:drug effects*; D045462:Endothelium-Dependent Relaxing Factors / Q000378:metabolism*; D066298:In Vitro Techniques; D008638:Mesenteric Arteries / Q000187:drug effects*; D009213:Myography; D009569:Nitric Oxide / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology*; D011453:Prostaglandins / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D001685:Biological Factors; D045462:Endothelium-Dependent Relaxing Factors; D011453:Prostaglandins; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; C067410:endothelium-dependent hyperpolarization factor; D010656:Phenylephrine; D009569:Nitric Oxide