Hypocretins, also known as orexins, are hypothalamic peptides that have been implicated in a variety of behaviors, e.g. food-seeking and feeding, arousal and sleep, reaction to stress. Disturbances in the central hypocretin neurotransmission are believed to underlie narcolepsy. It has also been postulated that hypocretins play an important role in the regulation of hypothalamus-pituitary-adrenal (HPA) axis, energy homeostasis, acquisition and learning of reward system-stimulating signals.

Interleukin 1 (IL-1) is one of the major proinflammatory cytokines responsible for the regulation of immune and inflammatory response. In this paper we present up-to date information concerning the mechanisms of intracellular signal transduction induced by this cytokine. Interleukin 1 effects on target cells are mediated via membrane receptors. One of them (type I) is responsible for interleukin 1 intracellular signaling, whereas the other (type II) is a natural regulator of the cytokine activity.