Orexin receptors R1 (OX1R) and OX2R mediate the action of the neuropeptides orexin A and orexin B. TCX-OX2-29 is an antagonist of OX2R (pKi = 7.5) that exhibits >250-fold selectivity for hOX2R compared with hOX1R (IC50s = 40 nM and >10,000 nM, respectively). It blocks the inhibitory action of orexin A on forskolin-induced cAMP formation.
