title: Resistance exercise acutely enhances mesenteric artery insulin-induced relaxation in healthy rats.
abstract: OBJECTIVE
  We evaluated the mechanisms involved in insulin-induced vasodilatation after acute resistance exercise in healthy rats.
  
  
  METHODS
  Wistar rats were divided into 3 groups: control (CT), electrically stimulated (ES) and resistance exercise (RE). Immediately after acute RE (15 sets with 10 repetitions at 70% of maximal intensity), the animals were sacrificed and rings of mesenteric artery were mounted in an isometric system. After this, concentration-response curves to insulin were performed in control condition and in the presence of LY294002 (PI3K inhibitor), L-NAME (NOS inhibitor), L-NAME+TEA (K(+) channels inhibitor), LY294002+BQ123 (ET-A antagonist) or ouabain (Na(+)/K(+) ATPase inhibitor).
  
  
  RESULTS
  Acute RE increased insulin-induced vasorelaxation as compared to control (CT: Rmax=7.3 ± 0.4% and RE: Rmax=15.8 ± 0.8%; p<0.001). NOS inhibition reduced (p<0.001) this vasorelaxation from both groups (CT: Rmax=2.0 ± 0.3%, and RE: Rmax=-1.2 ± 0.1%), while PI3K inhibition abolished the vasorelaxation in CT (Rmax=-0.1±0.3%, p<0.001), and caused vasoconstriction in RE (Rmax=-6.5 ± 0.6%). That insulin-induced vasoconstriction on PI3K inhibition was abolished (p<0.001) by the ET-A antagonist (Rmax=2.9 ± 0.4%). Additionally, acute RE enhanced (p<0.001) the functional activity of the ouabain-sensitive Na(+)/K(+) ATPase activity (Rmax=10.7 ± 0.4%) and of the K(+) channels (Rmax=-6.1±0.5%; p<0.001) in the insulin-induced vasorelaxation as compared to CT.
  
  
  CONCLUSIONS
  Such results suggest that acute RE promotes enhanced insulin-induced vasodilatation, which could act as a fine tuning to vascular tone.
authors: Department of Physiology, Federal University of Sergipe, 49100-000, São Cristóvão, SE, Brazil.
authors: M T
authors: MT
authors: Fontes
authors: Department of Physiology, Federal University of Sergipe, 49100-000, São Cristóvão, SE, Brazil.
authors: T L B T
authors: TL
authors: Silva
authors: Department of Physiology, Federal University of Sergipe, 49100-000, São Cristóvão, SE, Brazil.
authors: M M
authors: MM
authors: Mota
authors: Department of Physiology, Federal University of Sergipe, 49100-000, São Cristóvão, SE, Brazil.
authors: A S
authors: AS
authors: Barreto
authors: Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, 05508-900, São Paulo, SP, Brazil.
authors: L V
authors: LV
authors: Rossoni
authors: Department of Physiology, Federal University of Sergipe, 49100-000, São Cristóvão, SE, Brazil. Electronic address: marcio@infonet.com.br.
authors: M R V
authors: MR
authors: Santos
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D004730:Endothelium, Vascular / Q000378:metabolism*; D007328:Insulin / Q000008:administration & dosage / Q000378:metabolism*; D008297:Male; D008638:Mesenteric Arteries / Q000378:metabolism*; D010805:Physical Conditioning, Animal / Q000379:methods / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D014661:Vasoconstriction / Q000502:physiology; D014664:Vasodilation / Q000502:physiology*
chemical_list: D007328:Insulin
keywords: Exercise; Insulin; Mesenteric; Vascular endothelium