title: Acute increases in intraluminal pressure improve vasodilator responses in aged soleus muscle feed arteries.
abstract: OBJECTIVE
  We tested the hypothesis that exposure to an acute increase in intraluminal pressure, to mimic pressure associated with a bout of exercise, improves nitric oxide (NO)-mediated endothelium-dependent dilation in aged soleus muscle feed arteries (SFA) and that improved endothelial function would persist after a 2 h recovery period.
  
  
  METHODS
  SFA from young (4-month) and old (24-month) Fischer 344 rats were cannulated and pressurized at 90 (P90) or 130 (P130) cmH2O for 60 min. At the end of the treatment period, pressure in the P130 SFA was lowered to 90 cmH2O for examination of endothelium-dependent [flow or acetylcholine (ACh)] and endothelium-independent [sodium nitroprusside (SNP)] vasodilation. To determine the role of NO, vasodilator responses were assessed in the presence of N (ω)-nitro-L-arginine (L-NNA). To determine whether the effects of pressure persisted following a recovery period at normal pressure, SFA were pressurized to 130 cmH2O for 60 min and subsequently lowered to 90 cmH2O for 2 h before assessing function.
  
  
  RESULTS
  ACh- and flow-induced dilations were impaired in old SFA. Treatment with increased pressure for 60 min improved ACh- and flow-induced dilations in old SFA. SNP-induced dilation was improved in old and young SFA. The beneficial effect of pressure treatment on ACh- and flow-induced dilation in old SFA was blocked by L-NNA and was not present following a 2 h recovery period.
  
  
  CONCLUSIONS
  These results indicate that an acute increase in intraluminal pressure improves NO-mediated endothelium-dependent dilation in aged SFA; however, the beneficial effect does not persist after 2 h.
authors.affiliation: Department of Health and Kinesiology, Texas A&M University, MS 4243, College Station, TX, 77843-4243, USA, johnwseawright@hlkn.tamu.edu.
authors.forename: John W
authors.initials: JW
authors.lastname: Seawright
authors.forename: Meredith J
authors.initials: MJ
authors.lastname: Luttrell
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Woodman
mesh_terms: D000367:Age Factors; D000818:Animals; D001158:Arteries / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D004730:Endothelium, Vascular / Q000378:metabolism / Q000502:physiology; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000254:growth & development; D009131:Muscle, Smooth, Vascular / Q000378:metabolism / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism*; D005082:Physical Exertion; D011312:Pressure; D051381:Rats; D011916:Rats, Inbred F344; D014664:Vasodilation
chemical_list: D009569:Nitric Oxide