title: [Vasorelaxant effects of procyanidins on rabbit pulmonic ring in vitro].
abstract: OBJECTIVE
  To study the vasorelaxant effect of procyanidin (PC) extracted from grape seeds on rabbit thoracic pulmonic rings in vitro.
  
  
  METHODS
  Rabbits thoracic pulmonic rings were isolated, pre-contracted with noradrenalin (NA) and their responses to different concentrations of PC were investigated. The effects of endothelium and different signaling pathway inhibitors on PC-induced relaxation, including nitric oxide synthase inhibitor N(omega)-nitro-L-arginine (L-NNA), methylene blue (MB), prostaglandin synthase inhibitor indomethacin (Indo) and blockage of the adrenergic beta-receptor propranolol (Prop), were also assessed.
  
  
  RESULTS
  PC change the resting tension of rabbit's pulmonic rings but caused an obvious dose-dependent relaxation in 1 x 10(-6) mol x L(-) NA precontracted pulmonic rings (r = 0.69, P < 0.01). The relaxant effect of PC was significantly reduced by removal of endothelium or by treatment with either 1 x 10(-4) mol x L(-1) L-NNA or 1 x 10(-5) mol L(-1) MB, but not by treatment with prostaglandin synthase inhibitor or blockage of the adrenergic beta-receptor. In addition, PC (20 mg x L(-1)) dropped the dose-effect curves of NA, KCl and respectively on pulmonic rings denuded endothelium. PC can also inhibit the vasoconstriction caused by NA in the first phase, but has no impact on the constriction induced by CaCl2 in the second phase.
  
  
  CONCLUSIONS
  PC has an endothelium-dependent vasorelaxation on isolated rabbit's pulmonic rings, which is possibly mediated by nitric oxide (NO) pathways and blockage of receptor operated and voltage dependent calcium channels.
authors.affiliation: Department of Physiology, North Sichuan Medical College, Nanchong 637007, China.
authors.forename: Tuanxiao
authors.initials: T
authors.lastname: Zhang
authors.forename: Caiqin
authors.initials: C
authors.lastname: Niu
authors.forename: Haitao
authors.initials: H
authors.lastname: Lan
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.forename: Huae
authors.initials: H
authors.lastname: Jing
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D006331:Heart Diseases / Q000188:drug therapy / Q000503:physiopathology*; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D044945:Proanthocyanidins / Q000494:pharmacology*; D011651:Pulmonary Artery / Q000187:drug effects* / Q000503:physiopathology; D011817:Rabbits; D011897:Random Allocation; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D044945:Proanthocyanidins; D014665:Vasodilator Agents