title: Arginine vasopressin V1-antagonist and atrial natriuretic peptide reduce hemorrhagic brain edema in rats.
abstract: OBJECTIVE
  Injection of arginine vasopressin into the cerebral ventricles in animals with brain injury increased brain water, whereas injection of atrial natriuretic peptide reduced water content. Therefore, to determine the role of endogenous arginine vasopressin in brain edema, we attempted to inhibit edema from a hemorrhagic lesion with an arginine vasopressin V1 receptor antagonist or atrial natriuretic peptide.
  
  
  METHODS
  Adult Sprague-Dawley rats with hemorrhages induced by 0.4 IU bacterial collagenase were treated with 75 ng (n = 9) or 8 micrograms (n = 9) of the vasopressin V1 receptor antagonist d(CH2)5Tyr(Me)Arg, 3.2 micrograms (n = 4) atrial natriuretic peptide injected intracerebrally, or 5 micrograms/kg per hour (n = 7) atrial natriuretic peptide intraperitoneally. They were compared with control groups injected with 0.4 IU collagenase only. Brain water and electrolytes were measured 24 hours later. Brain uptake of [14C]sucrose was measured 30 minutes after lesions were induced by 0.4 IU collagenase alone (n = 5) or after collagenase injection and 50 micrograms/kg per hour (n = 5) atrial natriuretic peptide injected intravenously.
  
  
  RESULTS
  The arginine vasopressin V1 receptor antagonist and atrial natriuretic peptide significantly (p < 0.05) reduced water and sodium contents in the posterior edematous regions. Brain uptake of [14C]sucrose was significantly reduced by intravenous atrial natriuretic peptide.
  
  
  CONCLUSIONS
  Antagonists to arginine vasopressin V1 receptors and atrial natriuretic peptide both significantly reduce hemorrhagic brain edema, and atrial natriuretic peptide appears to protect the blood-brain barrier.
authors.affiliation: Neurology Service, Veterans Affairs Medical Center, Albuquerque, N.M.
authors.forename: G A
authors.initials: GA
authors.lastname: Rosenberg
authors.forename: O
authors.initials: O
authors.lastname: Scremin
authors.forename: E
authors.initials: E
authors.lastname: Estrada
authors.forename: W T
authors.initials: WT
authors.lastname: Kyner
mesh_terms: D057911:Angiotensin Receptor Antagonists; D000818:Animals; D001127:Arginine Vasopressin / Q000031:analogs & derivatives* / Q000494:pharmacology; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D001812:Blood-Brain Barrier / Q000187:drug effects; D001834:Body Water / Q000378:metabolism; D001929:Brain Edema / Q000209:etiology / Q000378:metabolism*; D002543:Cerebral Hemorrhage / Q000139:chemically induced / Q000150:complications*; D017364:Collagenases; D051381:Rats; D017207:Rats, Sprague-Dawley; D017483:Receptors, Vasopressin; D012964:Sodium / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism; D014667:Vasopressins / Q000037:antagonists & inhibitors
chemical_list: D057911:Angiotensin Receptor Antagonists; D017483:Receptors, Vasopressin; D014667:Vasopressins; D001127:Arginine Vasopressin; D013395:Sucrose; C025043:vasopressin, 1-(1-mercaptocyclohexaneacetic acid)-2-(O- methyl-L-tyrosine)-8-L-arginine-; D009320:Atrial Natriuretic Factor; D012964:Sodium; D017364:Collagenases