Learned food cues can drive feeding in the absence of hunger, and orexin/hypocretin signaling is necessary for this type of overeating. The current study examined whether orexin also mediates cue-food learning during the acquisition and extinction of these associations. In Experiment 1, rats underwent two sessions of Pavlovian appetitive conditioning, consisting of tone-food presentations. Prio...

The rostral ventromedial medulla (RVM) acts a key role in the descending inhibitory pain modulation. Neuropeptide orexin-A (ORXA) is confined to thousands of neurons in the lateral hypothalamus (LH). While RVM gets the orexinergic projections, the orexin receptors are also expressed in this structure. The aim of this study was to specify the cellular effects of ORXA on RVM neurons in vitro by u...

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 ...

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 ...

Orexinergic system may play an important role in the regulation of anesthesia-arousal. However, which region or which pathway mediated the effect of orexins was still unclear. In current study, we investigated whether activation of orexin signals in basal forebrain (BF) may alter electroencephalographic activity, induction and emergence time to sevoflurane anesthesia in rats. Either orexin-A or...

In humans, nonexercise activity thermogenesis (NEAT) increases with positive energy balance. The mediator of the interaction between positive energy balance and physical activity is unknown. In this study, we address the hypothesis that orexin A acts in the hypothalamic paraventricular nucleus (PVN) to increase nonfeeding-associated physical activity. PVN-cannulated rats were injected with eith...