Colony-stimulating factors in rapid eye movement sleep and non-rapid eye movement sleep regulation

Although several cytokines are known to be somnogenic, no study has been conducted to examine whether colony-stimulating factors (CSF) affect sleep. Therefore, we studied the effects of granulocyte-macrophage CSF (GM-CSF) and macrophage CSF (M-CSF) on sleep in rats and their possible mechanism of action. At the dose of 10 pmol, GM-CSF or M-CSF significantly increased both non-rapid eye movement and rapid eye movement (REM) sleep or REM sleep only when infused intracerebroventricularly during the dark period. When injected locally in the hypothalamus, GM-CSF and M-CSF increased nitric oxide (NO) production. Thus, NOergic neural signals in the hypothalamus may take part in the somnogenic action of CSF.