orexin A

Orexin A is a **neuropeptide** also known as hypocretin-1. It is one of two forms of orexin (the other being orexin B) produced by neurons in the hypothalamus. Orexin A regulates arousal, wakefulness, appetite, and energy expenditure. It acts primarily by binding to **orexin receptors OX1 and OX2** on neurons, promoting wakefulness and maintaining stable periods of alertness. Orexin A also plays a role in regulating feeding behavior, energy homeostasis, mood (with higher levels associated with positive mood states), and lipid metabolism by increasing glucose uptake, enhancing lipogenesis, inhibiting lipolysis, and stimulating adiponectin secretion. Dysfunction or loss of orexin A signaling is implicated in sleep disorders such as narcolepsy, while exogenous administration can increase wakefulness and food intake in animal models[2][6]. Orexin A is an endogenous peptide, not a marketed pharmaceutical product, though its receptor system is being targeted in drug development.

Other names

hypocretin-1hypocretin1hypocretin 1OXA