Inhibition of nitric oxide synthesis does not reduce infarct volume in a rat model of focal cerebral ischaemia.

The effect of the nitric oxide (NO) synthesis inhibitor Ng-nitro-L-arginine methylester (L-NAME) on ischaemic brain damage was determined in a rat model of focal cerebral ischaemia. Ischaemia was induced by permanent occlusion of the left middle cerebral artery (MCA) and infarction assessed 4 h post-occlusion by quantitative histopathology. L-NAME (30 mg/kg s.c.), administered 30 min pre- and 30 min post-MCA occlusion, did not significantly alter the volume of ischaemic damage in the cerebral hemisphere, neocortex or caudate nucleus compared with saline controls. This result provides no support for the view that NO generation is a key component in the post-ischaemic cascade leading to acute neuronal death.