Indole levels in human lumbar and ventricular cerebrospinal fluid and the effect of L-tryptophan administration

Levels of tryptophan (TRP), 5-hydroxytryptophan (5-HTP), 5-hydroxytryptamine (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) in human lumbar and ventricular cerebrospinal fluid (CSF) were measured by reversed phase liquid chromatography (HPLC) with electrochemical detection. The levels of TRP ranged from 1593 to 4865 nmol/l in ventricular (VF) and from 1257 to 2557 nmol/l in lumbar CSF. The level of 5-HTP varied from 1.1 to 68.9 nmol/l in VF and from 5.3 to 10.8 nmol/l in lumbar CSF; no previous reports of 5-HTP levels in CSF exist. The serotonin level was 1.9-27.3 nmol/l in VF and 5.7-12.0 nmol/l in lumbar CSF. The levels of 5-HIAA were considerably higher in VF than in lumbar fluid with respective means of 498 +/- 52.4 nmol/l and 112 +/- 15.6 nmol/l (P less than 0.001). An oral dose of 2 g L-tryptophan significantly increased all indole levels except that of 5-HT, both in patients with progressive myoclonus epilepsy and in controls.