Microdialysis amino acid analysis in a patient with severe head injury (illustrative case history 1) showing baseline values, values during ischaemic insult, and ratio (ischaemia value/baseline value) (CMA70 microdialysis catheter 10 mm membrane perfused with Ringer's solution at 0.3 μl/min). Valine and histidine were not available in this patient. Controversy surrounds the inhibitory role of glycine and taurine
| Amino acid type | Amino acid name | Base line value (μM) | Ischaemia value (μM) | Post-ischaemia value (μM) | Ratio (ischaemia value/baseline value) >1 increase <1 decrease |
|---|---|---|---|---|---|
| Excitatory | Glutamate | 6.77 | 228.1 | 42.8 | 33.7 |
| Aspartate | 2.32 | 32.6 | 10.8 | 14.1 | |
| Inhibitory | GABA | 0.06 | 35.7 | 0.08 | 595 |
| Glycine | 16.3 | 56.0 | 40.8 | 3.4 | |
| Taurine | 8.6 | 18.7 | 13.0 | 2.2 | |
| Non-transmitter | Alanine | 10.0 | 18.7 | 13.0 | 1.9 |
| Arginine | 34.6 | 184.5 | 135.9 | 5.3 | |
| Asparagine | 5.20 | 15 | 11.9 | 2.9 | |
| Citrulline | 1.59 | 6.9 | 4.67 | 4.3 | |
| Glutamine | 1738 | 931.5 | 1264 | 0.5 | |
| Methionine | 36.8 | 191.1 | 59.9 | 5.2 | |
| Phenylalanine | 22.8 | 78.5 | 45.6 | 3.4 | |
| Serine | 36.1 | 86.4 | 43.4 | 2.4 | |
| Threonine | 24.0 | 99.3 | 87.5 | 4.1 | |
| Tryptophan | 0.69 | 2 | 0.97 | 2.9 | |
| Tyrosine | 12.3 | 40.3 | 33.1 | 3.3 |