EPIDERMAL GROWTH-FACTOR ENHANCES SPONTANEOUS SLEEP IN RABBITS

Several growth factors are implicated in sleep regulation. Epidermal g rowth factor (EGF) is found in the brain, and it influences the produc tion of several sleep-promoting substances. We determined, therefore, whether administration of exogenous EGF affected spontaneous sleep in rabbits. Twenty-five rabbits were implanted with electroencephalograph ic electrodes, a brain thermistor, and an intracerebroventricular guid e cannula. Three doses of EGF (0.5, 5, and 25 mu g) were used. The ani mals were injected intracerebroventricularly with saline as control an d one dose of EGF on 2 separate days. Five and twenty-five micrograms of EGF enhanced non-rapid eye movement sleep and increased brain tempe rature. The 25-mu g dose of EGF also inhibited rapid eye movement slee p across the 23-h postinjection recording period. Results are consiste nt with the hypothesis that EGF, like other growth factors, could be i nvolved in sleep regulation.