CYTOKINE PRODUCTION DURING SLEEP AND WAKEFULNESS AND ITS RELATIONSHIPTO CORTISOL IN HEALTHY HUMANS

A growing body of evidence indicates that cytokines, especially interl eukin-1beta, are involved in the regulation of sleep and wakefulness. The aim of the present pilot study was to investigate the relationship between interleukin-1beta (IL-1beta) and gamma-interferon (gamma-IFN) production and the regulation of sleep and wakefulness. Four healthy male volunteers were investigated. After one adaptation night, beginni ng at 8 a.m. in the morning, the EEG was recorded by means of a mobile long-term EEG and blood samples were drawn every 45 min for the analy sis of IL-1beta, gamma-IFN and cortisol for 24 h. For the analysis of cytokines whole blood cultures were established. After 48 h of incubat ion in the presence of endotoxin Salmonella typhimurium, IL-1beta and gamma-IFN levels were measured in the culture supernatants using speci fic immunodetection assays. Methods of stochastic time series analysis were adopted to evaluate the biochemical data. Our results show the c apability of cultered blood cells to produce cytokines upon endotoxin challenge to be at a maximum around the time of sleep onset and during the first hours of sleep, declining during the night to a minimum lev el in the morning hours. The opposite was observed for cortisol. The a nalysis of autocorrelation functions gives evidence of a 24-hour rhyth m of cortisol and cytokines. The results indicate that the cytokines I L-1beta and gamma-IFN may play a role in sleep regulation.