DURATION OF GLUTAMATE RELEASE AFTER ACUTE ISCHEMIC STROKE

Background and Purpose High levels of glutamate in plasma and cerebros pinal fluid (CSF) have been demonstrated in patients with acute ischem ic stroke. The duration of this excitatory amino acid release has not been studied, and therefore the window of opportunity of treatment wit h glutamate antagonists is unknown. The aim of this investigation was to study the duration of the glutamate increase in patients with stabl e and progressing ischemic stroke. Methods Glutamate in CSF was measur ed by high-performance liquid chromatography in 184 patients with an a cute cerebral infarction of less than 24 hours' duration and in 43 con trol subjects, Results Among the 120 patients with stable ischemic str oke, median glutamate levels were significantly lower-and within the r eference range of control subjects-in those patients studied 6 to 24 h ours from onset of symptoms than in patients studied in the first 6 ho urs (3 [range, 2 to 10] versus 5 mu mol/L [range, 2 to 17]; P < .0001) . In 64 patients with progressing ischemic stroke, glutamate concentra tions measured at any time interval during the first 24 hours from ons et were significantly higher than in the stable stroke and control gro ups. Conclusions The presence of glutamate increase in the CSF cannot be documented for greater than 6 hours in stable ischemic stroke. The sustained elevation of glutamate observed in progressing stroke sugges ts that the window to prevent neurological deterioration may be wider.