We have previously shown that hypercapnic chemoreflex in prepro-orexin knockout mice (ORX-KO) is attenuated during wake but not sleep periods. In that study, however, hypercapnic stimulation had been chronically applied for 6 h because of technical difficulty in changing the composition of the inspired gas mixture without distorting the animal's vigilance states. In the present study we examine...

The neuropeptide orexin (hypocretin) increases energy expenditure partially through increasing spontaneous physical activity. The ability of exogenous orexin to alter body weight has never been established, however. We sought to determine whether orexin-A microinjected into the paraventricular nucleus of the hypothalamus (PVN) induced weight loss in rats. Chronic guide cannulae were implanted i...

Orexins, hypothalamic neuropeptides initially involved in the control of food intake and sleep-wake cycle, have recently emerged as pleiotropic regulators of different biological systems, including the reproductive axis. Besides central actions, peripheral expression and functions of orexins have been reported, and prepro-orexin and orexin type-1 receptor mRNAs have been detected in the testis....

Orexins (hypocretins) play a crucial role in arousal, feeding, and endocrine function. We previously reported that orexin-B activated respiratory neurons in the isolated brainstem-spinal cords of neonatal rats. We herein determined whether orexin-B antagonized respiratory depression induced by sevoflurane, propofol, or remifentanil. We recorded C4 nerve bursts as an index of inspiratory activit...

Orexin-A is an excitatory neuropeptide that mainly located in the lateral hypothalamus(LHA). Orexin-A can regulates multiple physiological activity that include arousal, wakefulness and appetite. We aim to discuss the effects of orexin-A on the glucose sensitive neurons in the hypothalamus, in order to make further investigation of potential mechanisms in the appetite system. Cerebral stereotax...

Wen-Dan Decoction (WDD), a formula of traditional Chinese medicine, has been clinically used for treating insomnia for approximately 800 years. However, the therapeutic mechanisms of WDD remain unclear. Orexin-A plays a key role in the sleep-wake cycle, while leptin function is opposite to orexin-A. Thus, orexin-A and leptin may be important factors in sleep disorders. In this study, 48 rats we...

Core body temperature (Tb) is influenced by many physiological factors, including behavioral state, locomotor activity, and biological rhythms. To determine the relative roles of these factors, we examined Tb in orexin knockout (KO) mice, which have a narcolepsy-like phenotype with severe sleep-wake fragmentation. Because orexin is released during wakefulness and is thought to promote heat prod...

The presence and distribution of cells positive to orexin A (OXA) and to orexin type 2 receptor (OX2R) were investigated in the gastrointestinal tract of neonatal dogs by means of immunohistochemical techniques. The orexin A-positive cells were identified with some of the endocrine cells in the stomach and in the duodenum; they were both of the open and closed type and were lacking in the large...

Orexin-A is a neuropeptide which has been suggested to be involved in sleep and arousal mechanisms. Orexin-A, for example, stimulates arousal when administrated intracerebroventricularly to rats. We attempted to identify specific neural sites of orexin-A and orexin-B action. Orexin-A and orexin-B were microinjected into the medial parvocellular subdivision of the paraventricular nucleus (PVN) i...