Orexin A human, rat, mouse has high affinity for OX1R, with 38 nM IC 50 and 34 nM EC 50 values in the the [Ca 2﹢ ]i transient assay.
Orexin A human, rat, mouse (3-30 mg/kg; i.v.; 5 min pre-test) significantly increases the latency to response at 10 and 30 mg/kg i.v. when given 5 min pre-test from 24.8±2.0 s in vehicle-treated mice to 35.0±3.7 s and 45.7±4.5 s, respectively. Orexin A human, rat, mouse (3, 10 and 30 mg/kg; i.v.) was given immediately before phenylp-quinone (PPQ) and increases the latency to the first PPQ-induced constriction from 357.4±35.2 s in vehicle-treated mice to 500.3±31.2 s at 10 mg/kg and 594.5±5.5 s at 30 mg/kg.