ee-581 and suvorexant

Orexins/hypocretins are key neuropeptides responsible for regulating central arousal and reward circuits. Two receptors respond to orexin signaling, orexin 1 receptor (OX(1)R) and orexin 2 receptor (OX(2)R) with partially overlapping nervous system distributions. Genetic studies suggest orexin receptor antagonists could be therapeutic for insomnia and other disorders with disruptions of sleep and wake. Suvorexant (MK-4305) is a potent, selective, and orally bioavailable antagonist of OX(1)R and OX(2)R currently under clinical investigation as a novel therapy for insomnia. Examination of Suvorexant in radioligand binding assays using tissue from transgenic rats expressing the human OX(2)R found nearly full receptor occupancy (>90%) at plasma exposures of 1.1 μM. Dosed orally Suvorexant significantly and dose-dependently reduced locomotor activity and promoted sleep in rats (10, 30, and 100 mg/kg), dogs (1 and 3 mg/kg), and rhesus monkeys (10 mg/kg). Consistent cross-species sleep/wake architecture changes produced by Suvorexant highlight a unique opportunity to develop dual orexin antagonists as a novel therapy for insomnia.

Topics: Animals; Area Under Curve; Azepines; Azides; CHO Cells; Cricetinae; Cricetulus; Dose-Response Relationship, Drug; Electrocardiography; Electromyography; Humans; Macaca mulatta; Motor Activity; Octreotide; Orexin Receptors; Protein Binding; Rats; Reaction Time; Receptors, G-Protein-Coupled; Receptors, Neuropeptide; Sleep; Transfection; Triazoles