The effects of electrical and chemical stimulation and electrolytic lesion of lateral hypothalamic area (LHA) on gastric ischemia-reperfusion injury (GI-RI) were investigated in rats whose celiac arteries were clamped for 30 min and reperfused for 60 min by removal of the clamp. The results are as follows. (1) Electrical stimulation of LHA could aggravate GI-RI in an intensity-dependent manner by using 0.2, 0.4 or 0.6 mA current respectively. Microinjection of L-glutamic acid into LHA resulted in a similar effect to that of electrical stimulation of LHA on GI-RI. After electrolytic lesion of bilateral LHA, the area of gastric mucosal injury induced by gastric ischemia-reperfusion (GI-R) was smaller than that by electrical stimulation of LHA plus GI-R. (2) Dorsal vagal complex (DVC) lesion or vagotomy could eliminate the effect of electrical stimulation of LHA on GI-RI. (3) Electrical stimulation of LHA increased the content of malondialdehyde (MDA) but decreased the activity of superoxide dismutase (SOD) of ischemia-reperfusion (I-R) gastric mucosa. (4) Electrical stimulation of LHA plus gastric I-R increased gastric juice volume and total acid output, but there were no significant changes in acidity, pepsin activity and gastric barrier mucus. These results indicate that the LHA is an area in the CNS exerting aggravate effects on GI-RI. The DVC and vagus may be involved in the regulative effects of LHA on GI-RI. These effects are associated with increases in gastric mucosal MDA content, gastric juice volume, and total acid output, and a decrease in SOD activity.Acidity, pepsin activity and gastric barrier mucus do not seem to play an important role.
Animals ; Electric Stimulation ; Gastric Mucosa ; blood supply ; metabolism ; pathology ; Hypothalamic Area, Lateral ; metabolism ; Male ; Malondialdehyde ; metabolism ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; metabolism ; pathology ; Superoxide Dismutase ; metabolism

In the present study, rat model of gastric ischemia-reperfusion (GI-R) injury was established by clamping the celiac artery for 30 min followed by 1 h of reperfusion. Subsequently, the regulatory effect of electrical stimulation of cerebellar fastigial nucleus (FN) on GI-R injury and its neural mechanisms were investigated in Sprague-Dawley rats. The results are as follows. Electrical stimulation of the cerebellar FN not only obviously attenuated the GI-R injury in an intensity-dependent manner, but also decreased the apoptosis rate of gastric mucosal cells. Chemical lesion of FN eliminated the protective effect of electrical stimulation of FN on GI-R injury. Electrical stimulation of cerebellar FN decreased both the frequency and amplitude of the discharges of greater splanchnic nerve, but it could not change the discharge of greater splanchnic nerve following the lesion of the lateral hypothalamic area (LHA). After bilateral section of the greater splanchnic nerves, electrical stimulation of the FN also attenuated the GI-R injury. Chemical lesion of the LHA reversed the protective effect of electrical stimulation of FN on GI-R injury. Electrical stimulation of FN increased the activity of superoxide dismutase (SOD), but decreased the content of malondialdehyde (MDA) in gastric mucosa under GI-R. These results indicate that the cerebellar FN may regulate GI-R injury. Therefore, the cerebellar FN is an important brain site protecting the stomach against GI-R. The LHA and greater splanchnic nerves participate in the regulatory effects of cerebellar FN stimulation on GI-R injury. In addition, antioxidation may also be involved in the protection mechanism of cerebellar FN stimulation.
Animals ; Apoptosis ; Cerebellar Nuclei ; physiology ; Electric Stimulation ; Gastric Mucosa ; cytology ; metabolism ; Hypothalamic Area, Lateral ; physiopathology ; Malondialdehyde ; metabolism ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; physiopathology ; Superoxide Dismutase ; metabolism

This study was aimed to investigate the changes of orexin-A (OXA) and neuropeptide Y (NPY) expression in the hypothalamus of the fasted and high-fat diet fed rats. For the experiments, the male Sprague-Dawley (SD) rats were used as the model of high-fat diet-induced obesity. The mean loss of body weight (MLBW) did not show the linear pattern during the fasting; from 24 h to 84 h of fastings, the MLBW was not significantly changed. The numbers of OXA-immunoreactive (IR) neurons were decreased at 84 h of fasting compared with those in other five fasting subgroups. The NPY immunoreactivities in the arcuate nucleus (ARC) and the suprachiasmatic nucleus (SCN) observed at 84 h of fasting were higher than that observed at 24 h of fasting. The number of OXA-IR neurons of the LHA (lateral hypothalamic area) in the high-fat (HF) diet fed group was more increased than that of the same area in the normal-fat (NF) diet fed group. The NPY immunoreactivities of the ARC and the SCN were higher in HF group than those observed in the same areas of NF group. Based on these results, it is noteworthy that the decrease of the body weight during the fast was not proportionate to the time-course, implicating a possible adaptation of the body for survival against starvation. The HF diet might activate the OXA and the NPY in the LHA to enhance food intake.
Adaptation, Physiological/physiology ; Animals ; Arcuate Nucleus/metabolism ; Dietary Fats ; Eating ; Fasting/*physiology ; Hypothalamic Area, Lateral/metabolism ; Hypothalamus/*metabolism ; Immunohistochemistry/veterinary ; Intracellular Signaling Peptides and Proteins/*metabolism ; Male ; Neuropeptide Y/*metabolism ; Neuropeptides/*metabolism ; Obesity ; Rats ; Rats, Sprague-Dawley/physiology ; Suprachiasmatic Nucleus/metabolism

Histaminergic neurons solely originate from the tuberomammillary nucleus (TMN) in the posterior hypothalamus and send widespread projections to the whole brain. Experiments in rats show that histamine release in the central nervous system is positively correlated with wakefulness and the histamine released is 4 times higher during wake episodes than during sleep episodes. Endogeneous prostaglandin E2 and orexin activate histaminergic neurons in the TMN to release histamine and promote wakefulness. Conversely, prostaglandin D2 and adenosine inhibit histamine release by increasing GABA release in the TMN to induce sleep. This paper reviews the effects and mechanisms of action of the histaminergic system on sleep-wake regulation, and briefly discusses the possibility of developing novel sedative-hypnotics and wakefulness-promoting drugs related to the histaminergic system.
Adenosine ; physiology ; Animals ; Dinoprostone ; physiology ; Histamine ; metabolism ; physiology ; Hypothalamic Area, Lateral ; physiology ; Intracellular Signaling Peptides and Proteins ; physiology ; Neurons ; physiology ; Neuropeptides ; physiology ; Orexins ; Prostaglandin D2 ; physiology ; Sleep ; physiology ; Wakefulness ; physiology ; gamma-Aminobutyric Acid ; metabolism