Orexin receptor type 1 (Ox1R or OX₁), also known as hypocretin receptor type 1 (HcrtR1), is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

that in humans is encoded by the HCRTR1

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

Function

The orexin 1 receptor (OX₁), is a

G-protein coupled receptor G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptors, and G protein-linked receptors (GPLR), form a large group of protein family, evolution ...

that is heavily expressed in projections from the

lateral hypothalamus The lateral hypothalamus (LH), also called the lateral hypothalamic area (LHA), contains the primary orexinergic nucleus within the hypothalamus that widely projects throughout the nervous system; this system of neurons mediates an array of cognit ...

and is involved in the regulation of feeding behaviour. OX₁ selectively binds the

orexin-A Orexin-A, also known as hypocretin-1, is a naturally occurring neuropeptide and orexin isoform. The orexinergic nucleus in the lateral hypothalamus is the primary orexin projection system in the brain. Structure Orexin-A is a peptide composed of 33 ...

neuropeptide. It shares 64% identity with OX₂.

Ligands

Agonists

Orexin-A Orexin-A, also known as hypocretin-1, is a naturally occurring neuropeptide and orexin isoform. The orexinergic nucleus in the lateral hypothalamus is the primary orexin projection system in the brain. Structure Orexin-A is a peptide composed of 33 ...

Antagonists

RTIOX-276 RTIOX-276 is an orexin antagonist. RTIOX-276 binds selectively to the orexin 1 receptor (KE = 8.5nM) and lacks significant affinity for the orexin 2 receptor (KE = > 10,000nM). RTIOX-276 may have therapeutic utility for the treatment of cocain ...

- Selective OX₁ antagonist *

ACT-335827 ACT-335827 is an orally available, selective orexin 1 receptor antagonist with anxiolytic effects in animals. Unlike other orexin receptor antagonists, ACT-335827 lacks sedative effects and was found to have no impact on sleep architecture ...

- Selective OX₁ antagonist *

Almorexant Almorexant, also known by its development code ACT-078573, is an orexin antagonist, acting as a competitive antagonist of the OX1 and OX2 orexin receptors, which was being developed by the pharmaceutical companies Actelion and GSK for the trea ...

- Dual OX₁ and OX₂

antagonist An antagonist is a character in a story who is presented as the chief foe of the protagonist. Etymology The English word antagonist comes from the Greek ἀνταγωνιστής – ''antagonistēs'', "opponent, competitor, villain, enemy, riv ...

Lemborexant Lemborexant, sold under the brand name Dayvigo, is an orexin antagonist medication which is used in the treatment of insomnia. It is indicated specifically for the treatment of insomnia characterized by difficulties with sleep onset and/or maint ...

- Dual OX₁ and OX₂

Nemorexant Daridorexant, sold under the brand name Quviviq, is an orexin antagonist medication which is used for the treatment of insomnia. Daridorexant is taken by mouth. Side effects of daridorexant include headache, somnolence, and fatigue. The medic ...

- Dual OX₁ and OX₂ antagonist *

SB-334,867 SB-334867 is an orexin antagonist. It was the first non-peptide antagonist developed that is selective for the orexin receptor subtype OX1, with around 50x selectivity for OX1 over OX2 receptors. It has been shown to produce sedative and anorec ...

- Selective OX₁ antagonist *

SB-408,124 SB-408124 is a drug which is a non-peptide antagonist selective for the orexin receptor subtype OX1, with around 70x selectivity for OX1 over OX2 receptors, and improved oral bioavailability compared to the older OX1 antagonist SB-334867 SB-3 ...

- Selective OX₁ antagonist *

SB-649,868 SB-649868 is a dual orexin receptor antagonist that was being developed by GlaxoSmithKline as a treatment for insomnia. A phase I clinical trial evaluated doses up to 80 mg, resulting in significant improvement in sleep latency without a ...

- Dual OX₁ and OX₂

Suvorexant Suvorexant, sold under the brand name Belsomra, is an orexin antagonist medication which is used in the treatment of insomnia. It is indicated specifically for the treatment of insomnia characterized by difficulties with sleep onset and/or mainte ...

- Dual OX₁ and OX₂

Function

Ligands

Agonists

Antagonists

See also

References

External links

Further reading