Orexin B amide (human) (trifluoroacetate salt) (Synonyms: Hypocretin 2, OXB)

Orexin B amide is a hypothalamic neuropeptide that regulates feeding behavior, wakefulness, and behavior under situations of high motivational relevance.¹ It is an agonist of orexin (OX) receptors with IC₅₀ values of 420 and 36 nM for human recombinant OX₁ and OX₂ receptors, respectively, expressed in CHO cells.² It induces transient increases in intracellular calcium in CHO cells stably expressing OX₁ and OX₂ (EC₅₀s = 2,500 and 60 nM, respectively) and in primary rat ventral tegmental area (VTA) dopaminergic neurons.^2,3 Orexin B amide stimulates arachidonic acid release from CHO cells expressing human recombinant OX₁ (EC₅₀ = 4.17 nM).⁴ It also stimulates food intake in freely feeding mice and goldfish when administered at intracerebroventricular doses of 30 nmol and 10 ng/g, respectively.^2,5

1.Mahler, S.V., Moorman, D.E., Smith, R.J., et al.Motivational activation: A unifying hypothesis of orexin/hypocretin functionNat. Neurosci.17(10)1298-1303(2014) 2.Sakurai, T., Amemiya, A., Ishii, M., et al.Orexins and orexin receptors: A family of hypothalamic neuropeptides and G protein-coupled receptors that regulate feeding behaviorCell92(4)573-585(1998) 3.Nakamura, T., Uramura, K., Nambu, T., et al.Orexin-induced hyperlocomotion and stereotypy are mediated by the dopaminergic systemBrain Res.873(1)181-187(2000) 4.Turunen, P.M., Ekholm, M.E., Somerharju, P., et al.Arachidonic acid release mediated by OX1 orexin receptorsBr. J. Pharmacol.159(1)212-221(2010) 5.Volkoff, H., Bjorklund, J.M., and Peter, R.E.Stimulation of feeding behavior and food consumption in the goldfish, Carassius auratus, by orexin-A and orexin-BBrain Res.846(2)204-209(1999)