Excitatory neuropeptide at orexin receptors (Ki values are 20 and 38 nM for OX1 and OX2 receptors respectively).
Orexin-A is synthesized by a cluster of neurons in the lateral hypothalamus and perifornical area. Orexin A is composed of 33 amino acids.
Uses and applications
The peptide is involved in a variety of physiological functions. E.g. feeding behavior, sleep/wake rhythms, thermoregulation, energy metabolism and cardiovascular activity. More recently orexins have been suggested to have a role in emotional regulation, energetic homeostasis, reward mechanisms, drug addiction, arousal system, sleep and wakefulness.
Excitatory neuropeptide at orexin OX1/OX2 receptors