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Description: Highly potent and selective OX2 antagonist; brain penetrant
Chemical Name: N-Ethyl-2-[(6-methoxy-3-pyridinyl)[(2-methylphenyl)sulfonyl]amino]-N-(3-pyridinylmethyl)-acetamide
Purity: ≥98% (HPLC)
Citations (4)
Literature (1)

Biological Activity for EMPA

EMPA is a highly potent, selective OX2 receptor antagonist (IC50 values are 2.3 nM and 1900 nM for OX2 and OX1 respectively). Displays negligible or no inhibition of a panel of 80 receptors. Blocks orexin-B- and orexin-A-invoked calcium mobilization in hOX2-expressing CHO cells (IC50 values are 7.9 nM and 8.8 nM respectively); reverses orexin-B-induced hyperlocomotion in mice. Brain penetrant.

Technical Data for EMPA

M. Wt 454.54
Formula C23H26N4O4S
Storage Store at -20°C
Purity ≥98% (HPLC)
CAS Number 680590-49-2
PubChem ID 9981404
Smiles O=C(CN(C2=CN=C(OC)C=C2)S(C3=C(C)C=CC=C3)(=O)=O)N(CC)CC1=CN=CC=C1

The technical data provided above is for guidance only. For batch specific data refer to the Certificate of Analysis.

Tocris products are intended for laboratory research use only, unless stated otherwise.

Solubility Data for EMPA

Solvent Max Conc. mg/mL Max Conc. mM
DMSO 45.45 100
ethanol 22.73 50

Preparing Stock Solutions for EMPA

The following data is based on the product molecular weight 454.54. Batch specific molecular weights may vary from batch to batch due to the degree of hydration, which will affect the solvent volumes required to prepare stock solutions.

Select a batch to recalculate based on the batch molecular weight:
Concentration / Solvent Volume / Mass 1 mg 5 mg 10 mg
1 mM 2.2 mL 11 mL 22 mL
5 mM 0.44 mL 2.2 mL 4.4 mL
10 mM 0.22 mL 1.1 mL 2.2 mL
50 mM 0.04 mL 0.22 mL 0.44 mL

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Product Datasheets for EMPA

Certificate of Analysis / Product Datasheet
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References for EMPA

References are publications that support the biological activity of the product.

Malherbe et al (2009) Biochemical and behavioural characterization of EMPA, a novel high-affinity, selective antagonist for the OX2 receptor. Br.J.Pharmacol. 156 1326 PMID: 19751316

Mochizuki et al (2011) Orexin receptor 2 expression in the posterior hypothalamus rescues sleepiness in narcoleptic mice. Proc.Natl.Acad.Sci.U.S.A 108 4471 PMID: 21368172

Malherbe et al (2010) Mapping the binding pocket of dual antagonist almorexant to human orexin 1 and orexin 2 receptors: comparison with the selective OX1 antagonist SB-674042 and the selective OX2 antagonist N-ethyl-2-[(6-methoxy-pyridin-3-yl)-(toluene- Mol.Pharmacol. 78 81 PMID: 20404073

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Keywords: EMPA, EMPA supplier, supplier, orexin, 2, receptor, OX2, antagonists, inhibits, potent, selective, hyperlocomotion, brain, penetrant, Receptor, 4558, Tocris Bioscience

4 Citations for EMPA

Citations are publications that use Tocris products. Selected citations for EMPA include:

Ralph J et al (2020) Orexin signaling in GABAergic lateral habenula neurons modulates aggressive behavior in male mice. Nat Neurosci 23 638-650 PMID: 32284606

Beig et al (2015) Both Ox1R and Ox2R orexin receptors contribute to the cardiorespiratory response evoked from the perifornical hypothalamus. Clin.Exp.Pharmacol.Physiol. 42 1059 PMID: 26174505

Jennifer J et al (2021) Orexin receptor antagonists reverse aberrant dopamine neuron activity and related behaviors in a rodent model of stress-induced psychosis. Transl Psychiatry 11 114 PMID: 33558469

Guerreiro et al (2015) The sleep-modulating peptide orexin-B protects midbrain DA neurons from degeneration, alone or in cooperation with nicotine. Mol.Pharmacol. 87 525 PMID: 25552485

Do you know of a great paper that uses EMPA from Tocris? Please let us know.

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Literature in this Area

Tocris offers the following scientific literature in this area to showcase our products. We invite you to request* your copy today!

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Peptides Involved in Appetite Modulation Scientific Review

Peptides Involved in Appetite Modulation Scientific Review

Written by Sonia Tucci, Lynsay Kobelis and Tim Kirkham, this review provides a synopsis of the increasing number of peptides that have been implicated in appetite regulation and energy homeostasis; putative roles of the major peptides are outlined and compounds available from Tocris are listed.