Clinical evaluation of extracellular amino acids in severe head trauma by intracerebral in vivo microdialysis.

The underlying mechanisms of neuronal dysfunction in head injury are multifactorial and not fully understood. Recent experimental evidence indicates that excitatory amino acids--for example, glutamate--may play a key part in secondary neuronal damage after head injury. A patient with severe head trauma was monitored for extracellular amino acids by intracerebral in vivo microdialysis. Very high concentrations of glutamate, glycine, and gamma-aminobutyric acid were recorded in the microdialysate specimens collected over three hours. In vivo microdialysis in head injury may prove to be a useful tool in understanding the pathogenesis of cell death in head trauma.