EMPA

• CAT Number: R042203
• CAS Number: 680590-49-2
• Molecular Formula: C23H26N4O4S
• Molecular Weight: 454.54
• Purity: ≥95%
• Synonyms: N-ethyl-2-[(6-methoxypyridin-3-yl)-(2-methylphenyl)sulfonylamino]-N-(pyridin-3-ylmethyl)acetamide
• InChI: InChI=1S/C23H26N4O4S/c1-4-26(16-19-9-7-13-24-14-19)23(28)17-27(20-11-12-22(31-3)25-15-20)32(29,30)21-10-6-5-8-18(21)2/h5-15H,4,16-17H2,1-3H3
• InChIKey: KJPHTXTWFHVJIG-UHFFFAOYSA-N
• SMILES: CCN(CC1=CN=CC=C1)C(=O)CN(C2=CN=C(C=C2)OC)S(=O)(=O)C3=CC=CC=C3C

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].
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].
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].

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.