| Bioactivity | EMPA is a high-affinity, reversible and selective orexin OX2 receptor antagonist. [3H]EMPA binds to human and rat OX2-HEK293 membranes with KD values of 1.1 and 1.4 nM respectively[1]. | |||||||||
| Invitro | EMPA competitively antagonizes orexin-A-and orexin-B-evoked accumulation of [3H]inositol phosphates (IP) at hOX2 receptors with pA2 values of 8.6 and 8.8 respectively[1]. EMPA displaces the [3H]EMPA binding from cell membranes containing human and rat OX2 receptors, with Ki values of 1.10±0.24 nM and 1.45±0.13 nM, respectively[1]. EMPA shows an IC50=5.75 µM, Ki=2.63 µM, and IC50=12.8 µM, Ki=5.8 µM in the binding assay at human and mouse V1a receptors, respectively[1].In CHO(dHFr-) cells stably expressing hOX2 receptors, EMPA inhibits orexin-A-or orexin-B-evoked [Ca2+]i response with IC50s of 8.8±1.7 nM and 7.9±1.7 nM, respectively[1]. | |||||||||
| In Vivo | EMPA (1-300 mg/kg; i.p.) dose-dependently reverses this [Ala11,D-Leu15]orexin-B-induced hyperlocomotion without itself significantly affecting locomotor activity (LMA) in male NMRI mice[1].EMPA (3-30 mg/kg; i.p.) induces a significant and dose-dependent reduction in the baseline LMA in france and male Wistar rats. EMPA (3-30 mg/kg; i.p.) demonstrates a clear dose-dependent inhibition of spontaneous activity as compared with vehicle-treated animals[1]. Animal Model: | |||||||||
| Name | EMPA | |||||||||
| CAS | 680590-49-2 | |||||||||
| Formula | C23H26N4O4S | |||||||||
| Molar Mass | 454.54 | |||||||||
| Appearance | Solid | |||||||||
| Transport | Room temperature in continental US; may vary elsewhere. | |||||||||
| Storage |
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| Reference | [1]. P Malherbe, et al. Biochemical and behavioural characterization of EMPA, a novel high-affinity, selective antagonist for the OX2 receptor. Br J Pharmacol. 2009 Apr; 156(8): 1326-1341. |