Extracellular glial fibrillary acidic protein and amino acids in brain regions of patients with subarachnoid hemorrhage--correlation with level of consciousness and site of bleeding

The extracellular fluid of two cortical regions was investigated in eight patients who underwent surgery for subarachnoid hemorrhage within 7-96 h after the rupture of an arterial aneurysm. Microdialysis samples, collected from the cortex of the ipsilateral gyrus rectus and temporal lobe for 52-127 h, were analyzed with respect to amino acids and the glial fibrillary acidic protein. In agreement with a previous study, an inverse relation was observed between total amino acid concentration and the level of consciousness. We also found that the concentration of glial fibrillary acidic protein was higher close to the bleeding site. Furthermorel we observed specific changes in the concentration of the protein and certain amino acids which coincided with clinical events such as increased intracranial pressure, vasospasm, ischemia and infarction. Finally, the concentrations of taurine may corroborate its function as an osmoequivalent. [Neural Res 1997; 19: 361-368]