Orexin B (human)

Product Name:Orexin B (human)

CAS No:205640-91-1

Purity:95%

Molar Mass:2899.36

Chemical Formula:C123H212N44O35S

Storage:Store at -20 degrees Celsius

Sequence:RSGPPGLQGRLQRLLQASGNHAAGILTM

Target:OX2R

Application:

Orexin B (human) is a neuropeptide involved in the regulation of wakefulness, appetite, and energy balance. It is one of two peptides produced from the prepro-orexin precursor, the other being Orexin A. Orexin B primarily binds to the orexin receptor 2 (OX2R), playing a key role in promoting arousal and sustaining wakefulness. This peptide is critical in maintaining the sleep-wake cycle and is closely associated with sleep disorders such as narcolepsy, where orexin signaling is disrupted. Research on Orexin B focuses on its functions in sleep regulation, appetite control, and its potential implications in treating sleep disorders and metabolic conditions.

Current Research:

Orexin B, also known as hypocretin-2, is a 28-amino acid neuropeptide derived from the prepro-orexin precursor. It is primarily produced in the lateral hypothalamus and plays an integral role in maintaining wakefulness, regulating energy homeostasis, and modulating various physiological processes. Orexin B interacts with two G protein-coupled receptors: orexin receptor 1 (OX1R) and orexin receptor 2 (OX2R), with higher affinity for OX2R.

Structure
Sequence: NH₂-LPLKYPGRRRLMYPDATDRQKWKMLK-CONH₂
Stability: The linear structure of Orexin B, without disulfide bridges, provides flexibility for receptor binding and functional activity.
Mechanism of Action
Orexin B binds primarily to OX2R and, to a lesser extent, OX1R, activating intracellular signaling pathways such as calcium influx, MAPK phosphorylation, and cyclic AMP (cAMP) production. These signaling events influence neuronal activity and coordinate arousal, energy balance, and autonomic functions.

Physiological Functions
Sleep-Wake Regulation:

Orexin B plays a critical role in promoting wakefulness and stabilizing sleep states. Dysfunction in the orexin system is linked to narcolepsy, particularly with cataplexy, due to loss of orexin neurons.
Energy Homeostasis:

It modulates feeding behavior, metabolism, and energy expenditure, contributing to the regulation of body weight and metabolic balance.
Autonomic Regulation:

Orexin B influences cardiovascular and thermoregulatory responses, coordinating autonomic nervous system activity.
Stress and Emotion:

The peptide is involved in modulating stress responses and emotional behaviors by interacting with the hypothalamic-pituitary-adrenal (HPA) axis.
Reward and Addiction:

Orexin B is implicated in reward-seeking behaviors and plays a role in addiction by affecting mesolimbic dopamine pathways.
Research Applications
Sleep Disorders:

Orexin B is used to study the pathophysiology of narcolepsy and other sleep-related conditions.
It serves as a target for developing orexin receptor agonists or antagonists to regulate sleep-wake cycles.
Obesity and Metabolism:

Its role in appetite regulation and energy expenditure makes it a focus of research on obesity and metabolic syndrome.
Stress and Behavior:

Orexin B is studied for its role in stress-induced behaviors and mood disorders.
Addiction Studies:

Research explores its involvement in reward circuits, providing insights into potential treatments for substance abuse disorders.
Neurodegenerative Diseases:

Orexin B's influence on neuronal excitability makes it relevant in research on conditions such as Alzheimer’s and Parkinson’s disease.
Handling and Storage
Form: Typically supplied as a lyophilized powder.
Storage: Store at -20°C in a desiccated environment to maintain stability.
Reconstitution: Reconstitute in sterile water or an appropriate buffer for experimental use.
Conclusion
Orexin B is a vital neuropeptide with diverse roles in sleep regulation, energy homeostasis, and stress modulation. Its specificity for OX2R and involvement in various physiological processes make it a critical target in research on sleep disorders, metabolic health, and neuropsychiatric conditions.

Reference:

Digby, J. E., Chen, J., Tang, J. Y., Lehnert, H., Matthews, R. N., & Randeva, H. S. (2006). Orexin receptor expression in human adipose tissue: effects of orexin-A and orexin-B. Journal of Endocrinology, 191(1), 129-136.