title: Contribution of nitric oxide synthase (NOS) activity in blood-brain barrier disruption and edema after acute ischemia/reperfusion in aortic coarctation-induced hypertensive rats.
abstract: Nitric oxide synthase (NOS) activity is increased during hypertension and cerebral ischemia. NOS inactivation reduces stroke-induced cerebral injuries, but little is known about its role in blood-brain barrier (BBB) disruption and cerebral edema formation during stroke in acute hypertension. Here, we investigated the role of NOS inhibition in progression of edema formation and BBB disruptions provoked by ischemia/reperfusion injuries in acute hypertensive rats.
  
  
  
  Rats were made acutely hypertensive by aortic coarctation. After 7 days, the rats were randomly selected for the recording of carotid artery pressure, or regional cerebral blood flow (rCBF) using laser Doppler. Ishcemia induced by 60-min middle cerebral artery occlusion (MCAO), followed by 12-h reperfusion. A single i.p. dose of L-NAME (1 mg/kg) was injected before MCAO. After evaluation of neurological disabilities, rats were slaughtered under deep anesthesia to assess cerebral infarction volume, edema, or BBB disruption.
  
  
  
  A 75-85% reduction in rCBF was occurred during MCAO which returned to pre-occluded levels during reperfusion. Profound neurological disabilities were evidenced after MCAO alongside with severe cerebral infarctions (628 ± 98 mm3), considerable edema (4.05 ± 0.52%) and extensive BBB disruptions (Evans blue extravasation, 8.46 ± 2.03 mug/g). L-NAME drastically improved neurological disabilities, diminished cerebral infarction (264 ± 46 mm3), reduced edema (1.49 ± 0.47%) and BBB disruption (2.93 ± 0.66 mug/g).
  
  
  
  The harmful actions of NOS activity on cerebral microvascular integrity are intensified by ischemia/reperfusion injuries during acute hypertension. NOS inactivation by L-NAME preserved this integrity and diminished cerebral edema.
authors: Dept. of Physiology, Shiraz University of Medical Sciences, Iran.
authors: Mohammad Taghi
authors: MT
authors: Mohammadi
authors: Dept. of Physiology, Shiraz University of Medical Sciences, Iran.
authors: Seyed Mostafa
authors: SM
authors: Shid Moosavi
authors: Dept. of Physiology, Shiraz University of Medical Sciences, Iran.
authors: Gholam Abbas
authors: GA
authors: Dehghani
mesh_terms: D000818:Animals; D001017:Aortic Coarctation / Q000150:complications* / Q000503:physiopathology; D001794:Blood Pressure / Q000187:drug effects; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology* / Q000503:physiopathology; D001929:Brain Edema / Q000150:complications / Q000201:enzymology* / Q000503:physiopathology; D002544:Cerebral Infarction / Q000150:complications / Q000473:pathology / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000187:drug effects; D006973:Hypertension / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D020244:Infarction, Middle Cerebral Artery / Q000150:complications / Q000473:pathology / Q000503:physiopathology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000008:administration & dosage / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010539:Permeability / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000150:complications* / Q000473:pathology / Q000503:physiopathology
chemical_list: D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester