Aminoguanidine ameliorates and L-arginine worsens brain damage from intraluminal middle cerebral artery occlusion. Academic Article uri icon

Overview

abstract

  • BACKGROUND AND PURPOSE: We studied whether the inducible nitric oxide synthase (iNOS) inhibitor aminoguanidine reduces focal cerebral ischemic damage in a relatively noninvasive stroke model in which the rat middle cerebral artery (MCA) is occluded using an intravascular filament. METHODS: In rats anesthetized with halothane, a nylon filament was advanced into the internal carotid artery until its tip occluded the origin of the MCA. The filament was left in place for 2 hours and then withdrawn. Twenty-four hours later, rats received intraperitoneal injections of aminoguanidine (100 mg/kg BID; n = 7), aminoguanidine+L-arginine (300 mg/kg QID; n = 7), L-arginine alone (n = 6), D-arginine alone (n = 6), or vehicle (n = 10). Drugs were administered for 3 consecutive days. Infarct volume was determined by image analysis in thionin-stained brain sections 4 days after ischemia. iNOS mRNA was detected with the use of reverse transcription polymerase chain reaction. RESULTS: Cerebral ischemia led to iNOS mRNA expression in the affected brain 48 hours after induction of ischemia. Administration of aminoguanidine reduced neocortical infarct volume by 26% (P < .05 versus vehicle, ANOVA and Tukey's test), a reduction that was antagonized by coadministration of L-arginine (P > .05 versus vehicle). Administration of L-arginine alone, but not D-arginine, enlarged the infarct by 29% (P < .05). Aminoguanidine or L-arginine did not influence the increase in water content in the postischemic brain, indicating that the effect on infarct volume is not related to modulation of ischemic edema. CONCLUSIONS: These results demonstrate that cerebral ischemia is also associated with iNOS expression in a minimally invasive model of transient MCA occlusion and that iNOS inhibition reduces focal ischemic damage. The findings support the hypothesis that nitric oxide produced by iNOS contributes to ischemic brain damage and that inhibition of iNOS may be a valuable tool in the management of cerebral ischemia.

publication date

  • February 1, 1996

Research

keywords

  • Arginine
  • Arterial Occlusive Diseases
  • Brain
  • Brain Damage, Chronic
  • Cerebral Arterial Diseases
  • Enzyme Inhibitors
  • Guanidines
  • Ischemic Attack, Transient
  • Nitric Oxide Synthase

Identity

Scopus Document Identifier

  • 0029670958

Digital Object Identifier (DOI)

  • 10.1161/01.str.27.2.317

PubMed ID

  • 8571430

Additional Document Info

volume

  • 27

issue

  • 2