Orexin-A

Orexin-A is a hypothalamic neuropeptide that belongs to the Orexin family (Orexin-A and Orexin-B) (1). Orexin neuropeptides -A and -B or Orexins are also known as Hypocretins. Orexin-A and –B are derived from the same precursor peptide (prepro-orexin) by proteolytic processing whose gene is located at human chromosome 17q21 (2). Orexins are produced by a small group of neurons located in the later hypothalamic and perifornical areas, with widespread projections to the entire neuroaxis (3). Orexinergic neurons of the lateral hypothalamus act as glucose sensors. Orexin signals hunger when blood glucose levels are low. Orexins also play a significant role in the regulation of sleep-wakefulness and body fluids and, in homeostatic regulation of energy metabolism, autonomic function and hormonal balance (4). Orexins mediate their effects by binding to two G-Protein-Coupled Receptors (OXR1 and OXR2). Orexin-A binds to both OXR1 and OXR2 with high affinity (5).

Orexin binding to its associated receptor activates the hypoxia-inducible factor 1 (HIF-1) transcription factor in the hypothalamus which results in increased glucose uptake and higher glycolytic activity. Mice lacking orexins or their cognate receptors eat less compared with matched littermates that do not lack them and, display a sleep disorder that is similar to human narcolepsy (6). Therefore, orexins are absent and/or greatly diminished in the brain and cerebrospinal fluid of most narcoleptic patients. Orexin-A is expressed in subthalamic nucleus, heart, lung, liver, kidney, pancreas, placenta and skeletal muscle. It is approximately a 16kDa protein (131 amino acids).

The ORXN-selective antibodies were generated against purified Orexin-A (ORXN) protein. ORXN-antibodies are affinity purified over immobilized antigen based chromatography, and the purified immunoglobulins are stabilized in antibody stabilization buffer. FabGennix Int. Inc., will also provide limited quantities of antigenic blocking protein for ORXN -101AP antibody. Antibodies to ORXN (ORXN -101AP) will label ~16kDa protein in Western blot positive control samples for ORXN and several other tissues. FabGennix Inc. will also conjugate antibodies with secondary enzymes (alk-Pase or HRP) or fluorescent probes upon request at nominal cost.

For research use only, not for diagnostic or therapeutic use.