Cerebrospinal fluid somatostatin and neuropeptide Y. Concentrations in aging and in dementia of the Alzheimer type with and without extrapyramidal signs.

Cerebrospinal fluid somatostatin and neuropeptide Y concentrations were measured in 26 healthy normal subjects, 27 patients with dementia of the Alzheimer type (DAT), and seven patients with DAT with extrapyramidal signs (EDAT). In healthy normal subjects, there was no significant correlation between age and either somatostatin or neuropeptide Y concentration. However, the concentrations of both peptides correlated significantly with each other. In patients with DAT and EDAT, the concentrations of somatostatin (17.5 +/- 5.0 and 16.4 +/- 5.0 pg/mL, respectively) were significantly reduced relative to age-matched control subjects (23.1 +/- 8.2 pg/mL) but were unrelated to dementia severity and did not change significantly during the progression of the disease. Neuropeptide Y concentrations did not differ significantly between the age-matched control, DAT, and EDAT groups (38.2 +/- 12.8, 37.0 +/- 12.3, and 30.3 +/- 7.8 pg/mL, respectively). These results suggest that in DAT, dysfunction of cortical somatostatin but not neuropeptide Y transmitter systems is reflected by reduced cerebrospinal fluid concentrations.