title: Role of GABAB receptor and L-Arg in GABA-induced vasorelaxation in non-diabetic and streptozotocin-induced diabetic rat vessels.
abstract: Hypertension is considered an independent risk factor for cardiovascular mortality in diabetic patients. The present study was designed to determine the role of gamma amino butyric acid B (GABAB) receptor and L-arginine (L-Arg) in GABA-induced vasorelaxation in normal and streptozotocin-induced diabetic rat vessels.
  
  
  
  Diabetes was induced by a single i.p. injection of streptozotocin (STZ, 60 mg/kg). Eight weeks later, superior mesenteric arteries of all groups were isolated and perfused according to the McGregor method.
  
  
  
  Baseline perfusion pressure of STZ diabetic rats was significantly higher than non-diabetic rats in both intact and denuded endothelium. In the presence of faclofen, a selective GABAB receptor blocker, GABA-induced relaxation in intact and denuded endothelium mesenteric beds of STZ diabetic rats was suppressed, but this response in non-diabetic rats was not suppressed. Our results showed that in the presence of L-Arg, a nitric oxide precursor, GABA induced vasorelaxation in both diabetic and non-diabetic vessels.
  
  
  
  From the results of this study, it may be concluded that the vasorelaxatory effect of GABA in diabetic vessel is mediated by the GABAB receptor and nitric oxide, but it seems that in non-diabetic vessel GABAB receptor does not play any role in GABA-induced vasorelaxation, but nitric oxide induced GABA relaxation in non-diabetic vessel.
authors: Dept. of Physiology, Faculty of Medicine, Molecular Medicine Research Center, Hormozgan University of Medical Science, Bandar Abbas, Iran.
authors: Fatemah
authors: F
authors: Kharazmi
authors: Dept. of Physiology, Faculty of Medicine, Molecular Medicine Research Center, Hormozgan University of Medical Science, Bandar Abbas, Iran.
authors: Nepton
authors: N
authors: Soltani
authors: Dept. of Physiology, Faculty of Medicine, Molecular Medicine Research Center, Hormozgan University of Medical Science, Bandar Abbas, Iran.
authors: Sana
authors: S
authors: Rezaei
authors: Dept. of Physiology, Faculty of Medicine, Tehran University
   of Medical Science, Tehran, Iran.
authors: Mansoor
authors: M
authors: Keshavarz
authors: Dept. of Physiology, Faculty of Medicine, Tehran University
   of Medical Science, Tehran, Iran.
authors: Leila
authors: L
authors: Farsi
mesh_terms: D000818:Animals; D001120:Arginine / Q000378:metabolism; D001794:Blood Pressure / Q000502:physiology*; D003921:Diabetes Mellitus, Experimental / Q000473:pathology*; D058788:GABA-B Receptor Antagonists / Q000494:pharmacology; D006973:Hypertension / Q000473:pathology; D008297:Male; D017538:Mesenteric Artery, Superior / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000378:metabolism*; D018080:Receptors, GABA-B / Q000378:metabolism*; D013311:Streptozocin; D014664:Vasodilation / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D058788:GABA-B Receptor Antagonists; D011963:Receptors, GABA-A; D018080:Receptors, GABA-B; D009569:Nitric Oxide; D005680:gamma-Aminobutyric Acid; D013311:Streptozocin; D001120:Arginine
keywords: Gamma amino butyric acid; Diabetes; GABAB receptor