Neuropeptides in cerebrospinal fluid in normal-pressure hydrocephalus and dementia.

Delta-sleep-inducing peptide (DSIP), vasoactive intestinal peptide (VIP), peptide YY (PYY) and somatostatin (SOM) were assayed with specific radioimmunological methods in cerebrospinal fluid (CSF) of healthy volunteers, 12 patients with Alzheimer's disease (AD), 11 patients with multi-infarct dementia (MID) and 10 patients with normal-pressure hydrocephalus (NPH). Patients with NPH were reinvestigated 3 months after a ventriculoperitoneal shunt operation. DSIP, PYY and SOM levels in CSF were decreased in patients with NPH compared to controls. The CSF concentration of SOM was also significantly reduced in patients with AD. No correlations were found between the degree of dementia in any of the illnesses and the CSF concentrations of the peptides. The concentration of DSIP, VIP and SOM increased significantly in parallel to the clinical improvement after the shunt operation in NPH patients.