CSF neurotransmitter metabolites in comatose head injury patients during changes in their clinical state

The main metabolites of noradrenaline, serotonin, and dopamine, methoxyhydroxyphenylglycol (MHPG), 5-hydroxyindole-acetic acid (5HIAA), and homovanillic acid (HVA), respectively, were assessed in CSF samples of patients in coma after severe head injury, the first days after the accident and again after an improvement (13 patients) or deterioration (7 patients) in their clinical state, evaluated by the score on the Glasgow Coma Scale. Improvement was accompanied by significant decreases in HVA and 5HIAA. In the patients who deteriorated, the levels of the three metabolites remained high. The results show that the increased turnover of CNS neurotransmitters in severe head injury normalizes during recovery. The use of noradrenaline, dopamine, and serotonin antagonists in brain injury experimental models may clarify the role of the increased biogenic amine turnover in the processes that lead to recovery. We propose relevant pharmacological intervention influencing neurotransmission in severe head injury.