[ala11, d-leu15]-orexin-b

**[ala11, d-leu15]-orexin-b** is a synthetic peptide and a highly potent, selective agonist of the orexin 2 receptor (OX2R, also known as hypocretin receptor 2)[1][3][5][7]. It has greater than 400-fold selectivity for OX2R over orexin 1 receptor (OX1R) (human EC50 0.13 nM for OX2R vs. 52 nM for OX1R)[1][3][5][7]. The compound induces calcium mobilization and inhibits forskolin-, PACAP-, or VIP-induced cAMP formation in primary neuronal cells[1]. It has been shown to increase mean arterial pressure, heart rate, and phrenic nerve activity in preclinical rat studies via intracranial administration[1]. The peptide sequence is derived from native orexin-B with specific substitutions (Ala at position 11 and D-Leu at position 15), conferring its selectivity profile[5][7]. The molecule is used in research for probing orexin receptor pharmacology, mechanisms of orexinergic signaling, and may have utility as a tool for exploring disorders of arousal and sleep[7]. It is not approved for therapeutic or diagnostic use in humans[1][5].

Other names

[Ala11,D-Leu15]-orexin B (acetate)[Ala11,D-Leu15]-OXB[Ala(11), D-Leu(15)]orexin-B