Intraspinal pressure influences CSF disposition of tryptophan and 5-HIAA

Cerebrospinal fluid (CSF) concentrations of monoamine compounds are influen ced by factors such as age, gender, height, body weight, tapping time, and atmospheric pressure. We have now examined the role of intraspinal pressure . Thirteen male volunteers underwent lumbar puncture in the right decubitus position without preceding strict bed rest. The intraspinal pressure was r ecorded, and monoamine precursors, transmitters, and metabolites were analy zed in two consecutively collected CSF fractions. Tryptophan in 12 ml of CS F and the 5-hydroxyindoleacetic acid concentration ratio [fraction II (7-12 ml CSF)/fraction I (0-6 ml CSF)] correlated with the intraspinal pressure. Hypothetically, the intraspinal pressure may be a confounding factor for a correct interpretation of CSF tryptophan and 5-hydroxyindoleacetic acid co ncentrations, and this is an issue that has to be addressed in future CSF s tudies. Copyright (C) 2001 S. Karger AG, Basel.