Function
The orexin neuropeptides, Orexin-A and Orexin-B, can excite neurons in the brain and affect multiple systems, including the acetylcholine, dopamine, histamine, and norepinephrine systems [1][2][3]. These orexin neuropeptides bind to two subtypes of orexin receptors, Orexin receptor 1 and Orexin receptor 2, both of which are G protein-coupled receptors (GPCRs) [4]. The GPCRs can sense a molecule outside the cell and send a signal through transduction in order to cause the cells to respond [5]. Thus, binding of the two can control wakefulness in humans. In studies, Orexin-B has shown to be more selective in binding, choosing to bind to Orexin receptor type 2 a majority of the time. Orexin-A has shown an equal selectivity at both types of receptors [1].
See also
Disease
Defects in orexin signaling are responsible for the human diseases of narcolepsy and insomnia[6].
Relevance
Belsomra or Suvorexant is a dual orexin receptor antagonist, and has the ability to block both Orexin receptors 1 and 2, thus inhibiting the neuropeptides from binding. By blocking this interaction, sleep can occur [7].
Structural highlights
The through a constricted solvent-accessible channel. A [8].
See also:
