The localization and number of oxytocin- and vasopressin-immunoreactive neurons (OXY-IR & VP-IR) and their fibers in the hypothalamic areas (supraoptic nucleus, paraventricular nucleus, lateral hypothalamic area and median eminence) of the hypophysectomized rat were compared with normal rats at 6 months of survival after surgery at the light microscopic level. The number of VP-IR neurons was markedly decreased in the supraoptic nucleus (SON) and paraventricular nucleus (PVN) in the hypophysectomized rats as compared to normal rats. Moreover, The number of VP-IR fibers was decresed in the SON, PVN, lateral hypothalamic area (LHA) and median eminence in the hypophysectomized rats. The number of OXY-IR neurons and thier fibers were also decreased in the SON and PVN in the hypophysectomized rats. The present results demonstrate that hypophysectomy induces a significant decrease in the number of OXY- and VPIR neurons and fibers within hypothalamic areas (SON, PVN, and LHA at 6 months of post-hypophysectomy) are decreased.
Animals ; Hypophysectomy ; Hypothalamic Area, Lateral ; Immunohistochemistry ; Median Eminence ; Neurons* ; Oxytocin* ; Paraventricular Hypothalamic Nucleus ; Rats* ; Supraoptic Nucleus ; Vasopressins

Brain natriuretic peptide (BNP) is a neuropeptide, isolated from porcine brain that is homologous with atriopeptin. Magnocellular neurosecretory cells located in the paraventricular nucleus and supraoptic nucleus synthesize and secrete neurohormones. The purpose of this study was to investigate distribution of BNP immunoreactivity throughout the rat hypothalamus from the day of birth to 30 days and adult using immunoperoxidase and immunofluorescent staining. The first BNP immunoreactive neurons appeared in the paraventricular and supraoptic nucleus at P10. In adult, BNP immunoreactivity was widely distributed throughout regions of the hypothalamus including dorsomedial hypothalamic nucleus, ventromedial hypothalamic nucleus, arcuate nucleus and internal layer of median eminence. The intensity of BNP immunoreactivity was weak in almost all hypothalamic nuclei except the paraventricular and supraoptic nuclei. BNP immunoreactivity was first observed in the lateral hypothalamic area at P15. In retrochiasmatic supraoptic nucleus, BNP immunoreactivity was first observed at P20 and remarkably distributed in adult. In the present study, distinct localization of BNP immunoreactivity was in the hypothalamic cell bodies and fibers. Although the role of BNP in the brain is yet to be determined, these results indicate that BNP in the neurons of hypothalamus play important role in the regulation of a variety of neurosecretory functions as a neuromodulator during postnatal development of the hypothalamus.
Adult ; Animals ; Arcuate Nucleus ; Brain* ; Dorsomedial Hypothalamic Nucleus ; Humans ; Hypothalamic Area, Lateral ; Hypothalamus* ; Immunohistochemistry ; Median Eminence ; Natriuretic Peptide, Brain ; Neurons* ; Neuropeptides ; Neurotransmitter Agents ; Paraventricular Hypothalamic Nucleus ; Parturition ; Rats* ; Supraoptic Nucleus ; Ventromedial Hypothalamic Nucleus

Brain natriuretic peptide (BNP) is a neuropeptide, isolated from porcine brain that is homologous with atriopeptin. Magnocellular neurosecretory cells located in the paraventricular nucleus and supraoptic nucleus synthesize and secrete neurohormones. The purpose of this study was to investigate distribution of BNP immunoreactivity throughout the rat hypothalamus from the day of birth to 30 days and adult using immunoperoxidase and immunofluorescent staining. The first BNP immunoreactive neurons appeared in the paraventricular and supraoptic nucleus at P10. In adult, BNP immunoreactivity was widely distributed throughout regions of the hypothalamus including dorsomedial hypothalamic nucleus, ventromedial hypothalamic nucleus, arcuate nucleus and internal layer of median eminence. The intensity of BNP immunoreactivity was weak in almost all hypothalamic nuclei except the paraventricular and supraoptic nuclei. BNP immunoreactivity was first observed in the lateral hypothalamic area at P15. In retrochiasmatic supraoptic nucleus, BNP immunoreactivity was first observed at P20 and remarkably distributed in adult. In the present study, distinct localization of BNP immunoreactivity was in the hypothalamic cell bodies and fibers. Although the role of BNP in the brain is yet to be determined, these results indicate that BNP in the neurons of hypothalamus play important role in the regulation of a variety of neurosecretory functions as a neuromodulator during postnatal development of the hypothalamus.
Adult ; Animals ; Arcuate Nucleus ; Brain* ; Dorsomedial Hypothalamic Nucleus ; Humans ; Hypothalamic Area, Lateral ; Hypothalamus* ; Immunohistochemistry ; Median Eminence ; Natriuretic Peptide, Brain ; Neurons* ; Neuropeptides ; Neurotransmitter Agents ; Paraventricular Hypothalamic Nucleus ; Parturition ; Rats* ; Supraoptic Nucleus ; Ventromedial Hypothalamic Nucleus

Chronic stress induces changes in neuronal functions in specific brain regions regulating sociability and mood-related behaviors. Recently we reported that stress-induced persistent upregulation of the neuropeptides orexin and melanin-concentrating hormone (MCH) in the basolateral amygdala (BLA) and the resulting activation of orexin receptors or MCH receptors within the BLA produced deficits in sociability and mood-related behaviors. In the present study, we investigated the neural targets that were innervated by BLA neurons containing orexin receptors or MCH receptors. The viral vector system AAV2-CaMKII-ChR2-eYFP was injected into the BLA to trace the axonal tracts of BLA neurons. This axon labeling analysis led us to identify the prelimbic and infralimbic cortices, nucleus accumbens (NAc), dorsal striatum, paraventricular nucleus (PVN), interstitial nucleus of the posterior limb of the anterior commissure, habenula, CA3 pyramidal neurons, central amygdala, and ventral hippocampus as the neuroanatomical sites receiving synaptic inputs of BLA neurons. Focusing on these regions, we then carried out stimulus-dependent c-Fos induction analysis after activating orexin receptors or MCH receptors of BLA neurons. Stereotaxic injection of an orexin receptor agonist or an MCH receptor agonist in the BLA induced c-Fos expression in the NAc, PVN, central amygdala, ventral hippocampus, lateral habenula and lateral hypothalamus, which are all potentially important for depression-related behaviors. Among these neural correlates, the NAc, PVN and central amygdala were strongly activated by stimulation of orexin receptors or MCH receptors in the BLA, whereas other BLA targets were differentially and weakly activated. These results identify a functional connectivity of BLA neurons regulated by orexin and MCH receptor systems in sociability and mood-related behaviors.
Axons ; Basolateral Nuclear Complex* ; Brain ; Central Amygdaloid Nucleus ; Depression ; Extremities ; Habenula ; Hippocampus ; Hypothalamic Area, Lateral ; Neurons* ; Neuropeptides ; Nucleus Accumbens ; Orexin Receptors* ; Paraventricular Hypothalamic Nucleus ; Pyramidal Cells ; Up-Regulation

This experimental studies was to investigate the location of CNS labeled neurons following injection of pseudorabies virus (PRV), Bartha strain, into the rat thymus. After survival times of 96~120 hours following injection of PRV, the rats were perfused, and their spinal cord and brain were frozen sectioned(30micrometer). These sections were stained by PRV immunohistochemical staining method, and observed with light microscope The results were as follows: 1. The PRV labeled spinal cord segments projecting to the rat thymus were founded in cervical and thoracic segments. Densely labeled areas of each spinal cord segment were founded in lamina V, VII, X, intermediolateral nucleus and dorsal nucleus. 2. In the rhombencephalon, PRV labeled neurons projecting to the thymus were founded in the A1 noradrenalin cells/C1 adrenalin cells/caudoventrolateral reticular nucleus, rostroventro-lateral reticular nucleus, medullary reticular nucleus, area postrema, nucleus solitary tract, nucleus raphe obscurus, nucleus raphe pallidus, nucleus raphe magnus, gigantocellular reticular nucleus, lateral paragigantocellular nucleus and spinal trigeminal nucleus. 3. In the mesencephalon, PRV labeled neurons were founded in parabrachial nucleus, Kolliker-Fuse nucleus, central gray matter, substantia nigra, nucleus dorsal raphe, A8 dopamin cells of retrorubral field, Edinger-Westphal nucleus, locus coeruleus, subcoeruleus nucleus and A5 noradrenalin cells. 4. In the prosencephalon, PRV labeled neurons were founded in reuniens thalamic nucleus, paraventricular thalamic nucleus, precommissural nucleus, paraventricular hypothalamic nucleus, anterior hypothalamic nucleus, lateral hypothalamic nucleus, preoptic hypothalamic nucleus, retrochiasmatic area, arcuate nucleus, dorsomedial hypothalamic nucleus and ventromedial hypothalamic nucleus. These results suggest that PRV labeled neurons of the spinal cord projecting to the rat thymus might be the neurons related to the viscero-somatic sensory and sympathetic preganglionic neurons, and PRV labeled neurons of the brain may be the neurons response to the movement of smooth muscle in blood vessels. These PRV labeled neurons may be central autonomic center related to the integration and modulation of reflex control linked to the sensory system monitoring the internal environment. These observations provide evidence for previously unknown projections from spinal cord and brain to the thymus which may be play an important role in the regulation of thymic function.
Animals ; Anterior Hypothalamic Nucleus ; Arcuate Nucleus ; Area Postrema ; Blood Vessels ; Brain ; Dorsomedial Hypothalamic Nucleus ; Herpesvirus 1, Suid* ; Hypothalamic Area, Lateral ; Immunohistochemistry ; Locus Coeruleus ; Mesencephalon ; Midline Thalamic Nuclei ; Muscle, Smooth ; Neurons* ; Paraventricular Hypothalamic Nucleus ; Prosencephalon ; Pseudorabies* ; Rats* ; Reflex ; Rhombencephalon ; Spinal Cord ; Substantia Nigra ; Thymus Gland* ; Trigeminal Nucleus, Spinal ; Ventromedial Hypothalamic Nucleus

BACKGROUND: Several studies have reported that cholecystokinin (CCK), a short-term meal related satiety signal, and leptin, long-term signal for controlling feeding behaviour and body weight, act synergistically to inhibit food intake. However the mechanism and neuroanatomical basis for this response remain unclear. To clarify the neuronal mechanisms underlying the synergistic interaction between leptin and CCK, we examined the neuron activated by single or combined injection of leptin and CCK in fasted rats using immunohistochemistry for Fos. The expression of Fos can be used to trace neuronal activation pathways. METHODS: The rats were divided into 4 groups; Tris solution-saline, Tris solution-CCK, leptin-saline, leptin-CCK. Rats were received a single intracerebroventricular injection of either 3mul Tris solution or 3microgram leptin, and a single intraperitoneal injection of either 2mul saline or 2microgram/kg sulfated CCK-8. The changes of the Fos expression were investigated in the paraventricular nucleus (Pa), retrochiasmatic area (RCh), lateral hypothalamic nucleus (LH), central nucleus of amygdala(Ce), supraoptic nucleus (SO), arcuate nucleus (Arc), ventromedial hypothalamic nucleus(VMH),dorsomedial hypothalamic nucleus (DM), ventral premammillary nucleus (PMV), superior lateral subdivision of parabrachial nucleus (LPBS), external lateral subdivision of parabrachial nucleus (LPBE), supragenual nucleus (SGe), area postrema (AP), medial area (SolM) and commissural area (SolC) of nucleus of the solitary tract nuclei. RESULTS: CCK increased the Fos expression in the Pa, RCh, LH, Ce, SO, Arc, VMH, DM, PMV, LPBS, LPBE and SolM. Leptin increased the Fos expression in the Pa, RCh, LH, SO, Arc, VMH, DM, PMV, LPBS, LPBE, SGe, AP and SolM. Injections of leptin and CCK significantly enhanced the Fos expression in the Pa, RCh, VMH, DM, LPBS, and SolM compared with those induced by leptin or CCK alone. CONCLUSION: Our results suggest that the Pa, RCh, VMH, DM, LPBS and SolM may be essential sites mediating the synergistic effect of leptin and CCK to regulate food intake.
Animals ; Arcuate Nucleus ; Area Postrema ; Body Weight ; Brain* ; Cholecystokinin* ; Eating ; Hypothalamic Area, Lateral ; Immunohistochemistry ; Injections, Intraperitoneal ; Leptin* ; Meals ; Negotiating ; Neurons ; Paraventricular Hypothalamic Nucleus ; Rats* ; Sincalide ; Solitary Nucleus ; Supraoptic Nucleus

The present study has been performed to investigate the neural axis of rat digastric muscle using viral tracer, pseudorabies virus. The upper nuclei to innervate digastric muscle were in accumbens nucleus, agran-ular insular cortex, central nucleus of amygaloid, lateral septal nucleus, frontal cortex, and subfornical organ etc, in telencephalon ; arcuate hypothalamic nucleus, lateral hypot-halamic area, medial preoptic nucleus, bed nucleus of stria terminalis, dorsomedial hypot-halamic nucleus, suprachiasmatic nucleus, paraventricular nucleus, and retrochiasmatic area etc, in diencephalon ; nucleus Darkschewitsch, interstitial nucleus of the medial logitudinal fasciculus, parabrachial nucleus, locus ceruleus, Kolliker-Fuse nucleus, trigeminal mesencephalic nucleus, red nucleus, substantia nigra, nucleus of posterior commissure, Edinger-Westphal nucleus, and dorsal raphe nucleus etc, in mesencephalon ; giganto-cellular reticular nucleus, raphe magnus nucleus, raphe pallidus nucleus, raphe obscuous nucleus, nucleus of solitary tracts, lateral reticular nucleus, parvocellular reticular nucleus, area postrema, facial nucleus, pontine reticular nucleus, pontine nucleus of trigeminal nerve and spinal nucleus of trigeminal nerve etc, in rhombencephalon. There are significant difference of numbers of PRV-Ba immunoreactive cells between right and left sides of brain in almost nuclei[P< 0.05]. But PRV-Ba immunoreactive cells were observed only ipsilaterally in accessory trigeminal motor nucleus, accessory facial nucleus and agranular insular cortex. Frontal cortex was the only area which were shown contralateral immunoreactivity. The results of this study provide anatomical support that both the cranial and caudal bellies are innervated by the same upper nuclei. The results also support the suggestion that the lower nuclei of digastric muscle, accessory trigeminal motor nucleus and accessory facial nucleus consist of somatotopic motor complex.
Animals ; Area Postrema ; Axis, Cervical Vertebra* ; Brain ; Diencephalon ; Herpesvirus 1, Suid ; Hypothalamic Area, Lateral ; Immunohistochemistry ; Locus Coeruleus ; Mesencephalon ; Paraventricular Hypothalamic Nucleus ; Raphe Nuclei ; Rats* ; Red Nucleus ; Rhombencephalon ; Septal Nuclei ; Subfornical Organ ; Substantia Nigra ; Suprachiasmatic Nucleus ; Telencephalon ; Trigeminal Nerve ; Trigeminal Nuclei

Chronic stress induces anxiety disorders, whereas physical exercise is believed to help people with clinical anxiety. In the present study, we investigated the mechanisms underlying stress-induced anxiety and its counteraction by exercise using an established animal model of anxiety. Mice treated with restraint for 2 h daily for 14 days exhibited anxiety-like behaviors, including social and nonsocial behavioral symptoms, and these behavioral impairments lasted for more than 12 weeks after the stress treatment was removed. Despite these lasting behavioral changes, wheel-running exercise treatment for 1 h daily from post-stress days 1 - 21 counteracted anxiety-like behaviors, and these anxiolytic effects of exercise persisted for more than 2 months, suggesting that anxiolytic effects of exercise stably induced. Repeated restraint treatment up-regulated the expression of the neuropeptide, melanin-concentrating hormone (MCH), in the lateral hypothalamus, hippocampus, and basolateral amygdala, the brain regions important for emotional behaviors. In an in vitro study, treatment of HT22 hippocampal cells with glucocorticoid increased MCH expression, suggesting that MCH upregulation can be initially triggered by the stress hormone, corticosterone. In contrast, post-stress treatment with wheel-running exercise reduced the stress-induced increase in MCH expression to control levels in the lateral hypothalamus, hippocampus and basolateral amygdala. Administration of an MCH receptor antagonist (SNAP94847) to stress-treated mice was therapeutic against stress-induced anxiety-like behaviors. These results suggest that repeated stress produces long-lasting anxiety-like behaviors and upregulates MCH in the brain, while exercise counteracts stress-induced MCH expression and persisting anxiety-like behaviors.
Animals ; Anti-Anxiety Agents ; Anxiety ; Anxiety Disorders ; Basolateral Nuclear Complex ; Behavioral Symptoms ; Brain* ; Corticosterone ; Exercise* ; Hippocampus ; Hypothalamic Area, Lateral ; In Vitro Techniques ; Mice ; Models, Animal ; Neuropeptides ; Up-Regulation*

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

The effects of administration of motilin into the lateral hypothalamic area (LHA) on gastric antrum motility in conscious rats and on gastric distention (GD) sensitive neurons in dorsal vagal complex (DVC) in anesthetized rats were studied. Microinjection of motilin (0.37 nmol/0.5 microl) into the LHA increased the gastric antrum motility index by 76.29 +/- 4.09% (P<0.01). In 60 GD sensitive neurons, firing rate increased in 39 neurons (65%) and decreased in 21 neurons (35%), which were classified as GD-excitatory and GD-inhibitory neurons, respectively. Firing rate by 7.17 +/- 7.89% within 1.5 min in 15 of 24 GD-excitatory neurons, and firing rate increased by 44.35 +/- 7.89% in 12 of 14 GD-inhibitory neurons after motilin microinjection into the LHA. The results suggest that exogenous motilin in LHA plays a role in the regulation of gastric antrum motility possibly via the vagal pathway from LHA-DVC to the stomach.
Animals ; Hypothalamic Area, Lateral ; drug effects ; Microinjections ; Motilin ; pharmacology ; Neurons ; drug effects ; physiology ; Pyloric Antrum ; drug effects ; physiology ; Rats ; Rats, Wistar ; Vagus Nerve ; drug effects ; physiology