introduction: previous studies have shown that stimulation of lateral hypothalamus (lh) produces antinociception. orexin-a (oxa) receptor is strongly expressed in the nucleus locus coeruleus (lc) and orexinergic fibers densely project from lh to lc. in this study, we assessed the role of lc and its oxa receptors in antinociceptive response induced by lh chemical stimulation in the rat. methods:...

Hypocretinergic (orexinergic) neurons in the lateral hypothalamus project to motor columns in the lumbar spinal cord. Consequently, we sought to determine whether the hypocretinergic system modulates the electrical activity of motoneurons. Using in vivo intracellular recording techniques, we examined the response of spinal motoneurons in the cat to electrical stimulation of the lateral hypothal...

An injection of orexin A or B into the cisterna magna or the rostral ventrolateral medulla (RVLM), where bulbospinal vasomotor neurons are located, elevated arterial pressure (AP) and heart rate (HR). We examined how orexins affected RVLM neurons to regulate cardiovascular functions by using in vitro recordings of neuronal activity of the RVLM and in vivo measurement of cardiovascular functions...

Fructose accounts for 10% of daily calories in the American diet. Fructose, but not glucose, given intracerebroventricularly stimulates homeostatic feeding mechanisms within the hypothalamus; however, little is known about how fructose affects hedonic feeding centers. Repeated ingestion of sucrose, a disaccharide of fructose and glucose, increases neuronal activity in hedonic centers, the nucle...

The pathophysiology underlying the pulsating quality of the pain of a migraine attack is not fully understood, although trigeminal vascular afferents containing the sensory neuropeptide calcitonin gene-related peptide (CGRP) must have a role. Antimigraine drugs, such as triptans, serotonin 5-hydroxytryptamine(1B/1D) receptor agonists, reproducibly block neurogenic vasodilation associated with C...

Chronic daily administration of nicotine and other drugs of abuse has been found to entrain pre- and post-drug circadian locomotor activity episodes that oscillate on a 24-h schedule and persist for several days after administration ceases. This drug-entrainable oscillator system could conceivably lead to circadian rhythms of drug seeking and drug use in human drug addicts. The present study (1...

A decrease in orexin-A (OX-A) levels has been reported to be associated with depression. It is also well known that stress and depression can disrupt neurogenesis in the dentate gyrus of the hippocampus; however, it is unclear how OX-A is involved in depression and/or neurogenesis. In the present study, we investigated the effect of i.c.v. administration of OX-A on the forced swimming test (FST...

introduction: it is known that acute and chronic stress induce hormonal and neuronal changes which affecting both pain threshold and nociceptive behaviours. orexin plays an important role in modulation of pain and stress. considering pain modulation during stress and the role of orexin in pain and stress, orexin might be involved in pain modulation during stress.we evaluated the involvement of ...

The orexin/hypocretin system has recently been implicated in reward-processing and addiction. We examined the involvement of the orexin system in cue-induced reinstatement of extinguished cocaine-seeking by administering the orexin 1 receptor antagonist SB-334867 (SB) or the orexin 2 receptor antagonist 4-pyridylmethyl (S)-tert-leucyl 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline (4PT) prior to ...

Consequences of prenatal alcohol exposure (AE) include motor hyperactivity, disrupted sleep and cognitive deficits. Hypothalamic orexin (ORX)-synthesizing neurons are important for the maintenance of vigilance and regulation of motor activity but their hyperactivity may contribute to anxiety disorders. Using a rat model, we tested whether ORX plays a role in behavioral consequences of prenatal ...