Orexin can increase neuronal excitability and induce epileptic activity. In this study, the effects of suvorexant (orexin receptor antagonist) on pentylenetetrazol (PTZ) and maximal electroshock (MES)-induced seizure were investigated. Mice were divided into 5 groups of six animals each including normal saline (10 ml/kg), diazepam (2 mg/kg) and suvorexant (50, 100 and 200 mg/kg) groups. In PTZ ...

There is significant variability in diet-induced obesity (DIO) among humans and rodents, which has been associated with differences in intrinsic spontaneous physical activity (SPA). The orexin neuropeptides positively modulate SPA through multiple brain sites, but the effects of DIO on orexin's activity are not well understood. In this study, we tested the hypothesis that DIO sensitivity is med...

A systematic review was conducted to categorize the types of cancerous tissues that express orexin receptors and also to examine the effect of in vitro administration of orexin A or B to corresponding cell samples. Comprehensive literature analyses of primary experimental studies were performed. The results of the review included an increased frequency of orexin receptor expression in many colo...

Although starvation-induced biochemical and metabolic changes are perceived by the hypothalamus, the adrenal gland plays a key role in the integration of metabolic activity and energy balance, implicating feeding as a major synchronizer of rhythms in the hypothalamic-pituitary-adrenal (HPA) axis. Given that orexins are involved in regulating food intake and activating the HPA axis, we hypothesi...

The absence of orexin results in narcolepsy-cataplexy. While the function of the central orexinergic system in sleep regulation has been well studied, the role of orexin in motor control is largely unknown. Here, we show that orexin-A acts via OX(1) and OX(2) receptors to directly depolarize neurons in the rat lateral vestibular nucleus (LVN), a subcortical motor center, and enhance their sensi...

Orexin-A and orexin-B are hypothalamic neuropeptides that play critical roles in the maintenance of wakefulness. Intracerebroventricular (ICV) administration of orexin-A has been shown to promote wakefulness and suppress both rapid eye movement (REM) sleep and non-REM (NREM) sleep through the orexin receptor-1 (OX(1)R) and orexin receptor-2 (OX(2)R). Here, we elucidated the differential roles o...

Orexins are found to participate in mediating stress-induced drug relapse. However, the neuroanatomical basis that orexin transmission modulates stress-induced drug seeking remains unknown. The nucleus accumbens shell (NAcSh), best known for its role in appetitive and negative motivation via dopamine receptors, is likely to be the potential important brain area where the orexin system mediates ...

Neurons in the lateral hypothalamus (LH) that contain hypocretin/orexin have been established as important promoters of arousal. Deficiencies in the hypocretin/orexin system lead to narcolepsy. The inhibition of hypocretin/orexin neurons by sleep-promoting neurotransmitters has been suggested as one part of the sleep regulation machinery. Adenosine has been identified as a sleep promoter and it...

NEW FINDINGS What is the central question of this study? Blockade of orexin receptors reduces blood pressure in spontaneously hypertensive rats (SHRs) but not in normotensive Wistar-Kyoto (WKY) rats, suggesting that upregulation of orexin signalling underlies the hypertensive phenotype of the SHR. However, it is not known what causes this upregulation. What is the main finding and its importanc...