oreksiinijärjestelmä
The oreksiinijärjestelmä, or orexin system, is a neuropeptide signaling pathway in the mammalian brain that plays a central role in regulating wakefulness, appetite, and energy balance. Orexins, also called hypocretins, are produced by neurons in the lateral and dorsomedial hypothalamus and are released into the cerebrospinal fluid and synaptic clefts. The peptides exist as two isoforms, orexin‑A (hypocretin‑1) and orexin‑B (hypocretin‑2), which bind to two G‑protein‑coupled receptors, OX1R and OX2R. These receptors are widely distributed in the central nervous system and in peripheral tissues, enabling orexins to influence a variety of physiological processes.
Functionally, the oreksiinijärjestelmä enhances arousal and vigilance through stimulation of cortical and subcortical arousal centers, including
In clinical research, orexin receptor antagonists have been developed as treatments for insomnia, exploiting the ability