The orexin A and orexin B receptors (also known as hypocretin 1 and 2) are found in the perifornical area/latero-posterior hypothalamus, and projections from this area cover much of the brain. These receptors have been implicated in various neurophysiological and neuropsychological disorders such as narcolepsy, insomnia, drug addiction, anxiety, and migraine headaches. The orexin-B-SAP conjugate consists of the rat/mouse orexin-B peptide conjugated to saporin. Orexin-B binds to the hypocretin (HCRT)-2 receptor with approximately 5-times greater affinity than to the HCRT-1 receptor.
Orexin-B-SAP is a bonded toxin between orexin-B and the ribosome-inactivating protein, saporin. It eliminates cells expressing the HCRT-2 receptor.