[Physiopathology of neurotransmitter metabolites in the cerebrospinal fluid in brain tumors].

The results in the group of III ventricle tumors, that is a decrease in the ventricular concentration of 5-HIAA in CSF, show that the hypothalamic metabolism of 5-HT is of importance for the concentration of 5-HIAA in the CSF. The results in posterior fossa tumors and in non communicating hydrocephalus (non tumor patients) for 5-HIAA and HVA confirm that the reabsorption of the metabolites from CSF occurs mainly in the caudal region of the ventricular system: the data in communicating hydrocephalus demonstrate that the intracranial hypertension can interfere by itself with the out transport mechanism of the metabolites from CSF. The results in normotensive idiopathic hydrocephalus sustain the hypothesis of a disturbance in 5-HT metabolism: it seems possible to separate this group from patients with secondary hydrocephalus in which the intracranial hypertension is only clinically compensated. The results in lumbar determinations demonstrate that in intracranial hypertension there is an impairment of the reabsorption of 5-HIAA also in the lumbar subarachnoid spaces. The concentration of 5-HIAA can depend mainly on the spinal cord metabolism, while lumbar HVA derives from the brain metabolism.