Related Experiment Video
Updated: Dec 23, 2025
Polygraphic Recording Procedure for Measuring Sleep in Mice
Published on: January 25, 2016
Pharmacological characterization of a novel potent, selective, and orally active orexin 2 receptor antagonist,
Shunsuke Maehara1, Natsuko Yuge1, Chika Higashi1
1Biology Laboratory, Discovery Research, Mochida Pharmaceutical Co., Ltd., Gotemba, Japan.
Aims:
Recently, we identified a novel orexin 2 (OX2 ) receptor antagonist, SDM-878 (2-(3-(2-(1H-pyrazol-1-yl)nicotinoyl)-3,8-diazabicyclo[3.2.1]octan-8-yl)-3-methoxyisonicotinonitrile). The purpose of the present study is to characterize the in vitro and in vivo pharmacological effects of SDM-878.
Methods:
The in vitro potency and selectivity of SDM-878 were examined in CHO cells that exhibit stable expression of human orexin 1 (OX1 ), human orexin 2 (OX2 ), rat OX1 , and rat OX2 receptors. Then, the plasma half-life, oral bioavailability, and brain penetration of SDM-878 were examined in rats. The in vivo effect of SDM-878 in rats was tested using electroencephalography (EEG). The target engagement of SDM-878 in the rat brain was examined using the antagonistic effect against hyperlocomotion caused by the intracerebroventricular administration of the OX2 receptor agonist, ADL-OXB ([Ala11 , d-Leu15 ]-orexin B).
Results:
SDM-878 showed potent inhibitory activities for human and rat OX2 receptors with IC values of 10.6 and 8.8 nM, respectively, and approximately 1000-fold selectivity against the OX1 receptor. In rat studies, SDM-878 exhibited a relatively short half-life in plasma, oral bioavailability, and good brain penetration. These data indicate that SDM-878 is a potent, selective, orally active, and brain-penetrable OX2 receptor antagonist. In behavioral studies using rats, SDM-878 (100 mg/kg) antagonized hyperlocomotion caused by intracerebroventricular administration of ADL-OXB. SDM-878 exhibited a potent sleep-promoting effect at the same dose (100 mg/kg) in a rat EEG study.
Conclusion:
Our results suggest that SDM-878 is likely to be a good pharmacological tool for investigating the role of the OX2 receptor and may have therapeutic potential for the treatment of insomnia.
More Related Videos
08:37Identification of Orexin and Endocannabinoid Receptors in Adult Zebrafish Using Immunoperoxidase and Immunofluorescence Methods
Published on: June 25, 2019
09:09Preparation and Delivery of Protein Microcrystals in Lipidic Cubic Phase for Serial Femtosecond Crystallography
Published on: September 20, 2016
Related Concept Videos
01:17Sedatives and Hypnotics Drugs: Miscellaneous Agents
Melatonin congeners like ramelteon (Rozerem) and tasimelteon (Hetlioz) selectively bind to melatonin receptors (MT1 and MT2) and thus mimic the actions of melatonin, a hormone that regulates sleep-wake cycles. Tasimelteon is primarily used for non-24-hour sleep-wake disorder, common in blind patients. They are also used to treat conditions like insomnia...
01:22Opioid Receptors: Overview
01:25Drug-Receptor Interaction: Agonist
Agonists can bind to receptors in different ways. Some agonists bind directly to the receptor's active site, mimicking the endogenous...
01:28Drug-Receptor Interaction: Antagonist
Antagonists can be classified as competitive or noncompetitive based on their...
01:25Adrenergic Agonists: Indirect-Acting Agents
One mechanism involves depleting stored catecholamines by displacing them from synaptic vesicles. These agents, known as "displacers," are transported into vesicles at the expense of noradrenaline. Examples include amphetamine and tyramine, which lack a catechol moiety, resulting in prolonged action, improved oral...
01:16Adrenergic Agonists: Chemistry and Structure-Activity Relationship
Aromatic ring substitutions: Substituting the aromatic ring with –OH groups at positions 3 and 4 yields catecholamines (e.g., epinephrine), which have a high affinity for adrenoceptors. Hydrogen bonding between –OH groups and receptors enhances adrenergic activity.
Separation of...