Chronic alcohol intake can profoundly modify the neuronal activity and the morphologic structure of hypothalamic nucleus in the rat brain. The aim of the present study is to observe the effects of chronic alcohol intake on expression of vasopressin and oxytocin in the paraventricular and supraoptic nucleus in the rat hypothalamus. Experimental rats (n=14) were divided into control group and chronic alcohol group. Chronic alcohol group was induced via daily liquid alcohol intake for 6 months beginning at 8 weeks of age. As a result, the number of vasopressin and oxytocin-containing neurons was decreased in the paraventricular and supraoptic nucleus in chronic alcohol group. Especially, the number of vasopressin-containing neurons of chronic alcohol group was significantly decreased in the paraventricular nucleus. Chronic alcohol intake produced significant changes in the volume of the cell bodies and their nucleus in neurons of the paraventricular and supraoptic nucleus. Particularly, the size of nucleus of vasopressin-containing neurons in chronic alcohol group was larger than in control group. These results show that chronic alcohol intake may affect the synthesis of vasopressin and oxytocin in the neurons of hypothalamic nuclei. Whereas, chronic alcohol intake induces an enlargement of the cell size of surviving neuron to compensate.
Animals ; Brain ; Cell Size ; Hypothalamus* ; Neurons* ; Oxytocin ; Paraventricular Hypothalamic Nucleus ; Rats* ; Supraoptic Nucleus* ; Vasopressins*

Previous studies have shown that hypertonic saline induces c-fos expression in the magnocellular neurons of rat hypothalamus. The present immunohistochemical double-labeling study was undertaken to determine the identification of magnocellular neurons expressing c-Fos in response to osmotic stimulus. Hypertonic saline induced c-Fos-like immunoreactivity (FLI) in various regions of hypothalamus in addition to supraoptic nucleus (SON) and paraventricular nucleus (PVN). FLI was detected in most of oxytocin neurons in the preoptic region and in the accessory nuclei located between the PVN and SON as well as in the SON and PVN. In particular, most of all oxytocin neurons in the accessory nuclei were labeled for c-Fos. There were also many FLI cells that did not show oxytocin and vasopressin immunore-acitivity in their cytoplasm. Relative frequencies of oxytocin and vasopressin neuronal responses showed that much more cells of oxytocin than vasopressin were induced to express c-fos in response to hypertonic saline. These data show that both oxytocin and vasopressin neurons are sensitive to osmotic stimulus and activated via expression of c-Fos by hypertonic saline.
Animals ; Cytoplasm ; Hypothalamus ; Neurons* ; Oxytocin ; Paraventricular Hypothalamic Nucleus ; Rats ; Supraoptic Nucleus ; Vasopressins

Previous studies by others have shown that administration of hypertonic saline (HS) induces c-fos expression in rat brain and old fibroblast cells are defective in transcription of c-fos in response to serum. The present immunohisto-chemical studies were undertaken to determine 1) the time that c-fos is expressed during the postnatal development of rat brain and 2) if there is aging-related change of c-fos expression in the osmoresponsive neurons after osmotic stimulus. Fos-like immunoreactivity (FLI) in response to HS treatment began to be detected dramatically at postnatal day (P) 14 in hypothalamic paraventricular nucleus (PVN), supraoptic nucleus (SON), and organum vasculosum lamina terminalis (OVLT). Intensity of FLI and number of Fos immunoreactive cells induced by HS were substantially reduced as rats age. Our data demonstrate for the first time that c-fos induction is decreased in aging-dependent manner and the time of c-fos induction during postnatal development is coincided with the status of differentiation in rat brain. We will interpret these findings in relation to synaptogenesis, and maturation or disability of signal transduction pathways in osmoresponsive neurons in rat brain.
Aging* ; Animals ; Brain ; Fibroblasts ; Hypothalamus ; Neurons* ; Osmoregulation* ; Paraventricular Hypothalamic Nucleus ; Rats* ; Signal Transduction ; Supraoptic Nucleus

The purpose of this study was to investigate the ontogeny of oxytocin- and vasopressin-specific neurons in the supraoptic and paraventricular nuclei of the human fetal hypothalamus. Eight human fetuses, 17- to 22-week gestation, were used in this study. Tissues of fetal hypothalami were fixed with 10% neutral buffered formalin, embedded in paraplast, and cut serially in coronal planes. Representative sections were stained with cresyl violet for the contour of both nuclei and monoclonal antibodies to oxytocin and vasopressin were used for immunohistochemistry. In the hypothalamus, oxytocin- and vasopressin-specific neurons were first observed in a 18-week fetus. In the fetus oxytocin-specific neurons were observed in both supraoptic and paraventricular nucleus and vasopressin-specific neurons were observed only in the supraoptic nucleus. Both neurons were observed in both nuclei of the fetuses and after 19-week of gestation. In both nuclei, oxytocin-specific neurons predominate in number in each stages. The shape of two cell types was mostly oval, and no significant differences of the size between two in each stages.
Antibodies, Monoclonal* ; Fetus* ; Formaldehyde ; Humans* ; Hypothalamus ; Immunohistochemistry ; Neurons* ; Oxytocin ; Paraventricular Hypothalamic Nucleus ; Pregnancy ; Supraoptic Nucleus ; Vasopressins ; Viola

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 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 and fluorescence intensity of BNP immunoreactivity throughout the rat hypothalamus using immunoperoxidase and immunofluorescent staining. BNP immunoreactivity was widely distributed throughout regions of the hypothalamus. Immunoreactive perikarya were observed only in the paraventricular nucleus and supraoptic nucleus, and many immunoreactive fibers with BNP were observed in the other hypothalamic nuclei including these nuclei. Difference of staining intensity between paraventricular nucleus and supraoptic nucleus was not found on light microscope but fluorescence intensity was higher in the supraoptic nucleus than in the paraventricular nucleus on confocal laser scanning microscope. 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.
Animals ; Brain* ; Fluorescence ; Hypothalamus* ; Immunohistochemistry ; Natriuretic Peptide, Brain* ; Neurons ; Neuropeptides ; Neurotransmitter Agents ; Paraventricular Hypothalamic Nucleus ; Rats* ; Supraoptic Nucleus

The role of neuropeptides in the central nervous system (CNS) has received increasing attention. Numerous peptide molecules are found in the mammalian CNS and many of them are thought to act as either neurotransmitters or neuromodulators. The neuropeptides found in high concentration in the hypothalamus include vasopressin (VP), vasoactive intestinal polypeptide, somatostatin, and oxytocin. The main approches to assess the involvement of neuropeptides can be focused on functions affecting the aging of the brain. Morphological aging of the CNS has been characterized by degenerative changes of fiber connections and cell loss, although degeneration does not always occur to the same extent throughout various parts of the brain and, moreover, varies for different cell types. Despite of many studies in VP containing neurons , there exist discrepancies in results about the changes of aged rat brain. The aim of the present study is, therefore, to investigative possible changes in the number and morphology of VPimmunoreactive neurons with aging in each area of the hypothalmus of the aged rats. As a result, the number of VP-immunoreactive neurons was decreased in hypothalamus nucleus of aged group. Especially, in VP-immunoreactive neurons of hypothalamus, the size of neuronal cell body and nuclei in aged group is larger than in young group and the fiber density of immunoreactivity neurons of median eminance (ME) in aged group is stronger than in young group. But, the total number of VP-immunoreactive neurons in the suprachiasmatic nucleus (SCN) of the aged group is larger than in the young group. These studies indicate the involvement of VP-immunoreactive neurons in aging process of hypothalamus, and aging process may affect the synthesis of VP in the neurons of hypothalamic nuclei. Whereas, in VP expression, aging process induces an enlargement of the cell size of surviving neurons to compensate.
Aging ; Animals ; Brain ; Cell Size ; Central Nervous System ; Hypothalamus* ; Neurons* ; Neuropeptides ; Neurotransmitter Agents ; Oxytocin ; Paraventricular Hypothalamic Nucleus ; Rats* ; Somatostatin ; Suprachiasmatic Nucleus ; Supraoptic Nucleus ; Vasoactive Intestinal Peptide ; Vasopressins

BACKGROUND AND OBJECTIVES: The vestibuloautonomic reflex controls respiration and blood pressure during locomotion. The purpose of this study was to investigate the role of the peripheral vestibular receptor in the control of blood pressure in sinoaortic denervated (SAD) rats. MATERIALS AND METHODS: The baroreceptor reflex was removed by SAD in labyrinthectomized rats. The expression of c-Fos protein in the vestibular nuclear complex, and other nuclei related to control of blood pressure, was measured following the induction of acute hypotension using sodium nitroprusside (SNP). RESULTS: The SNP induced acute hypotension, in intact labyrinthine rats, increased the expression of c-Fos protein in the supraoptic nucleus, paraventricular nucleus, rostral ventrolateral medulla, solitary nucleus, and vestibular nuclear complex. The expression of c-Fos protein, following the SNP induced acute hypotension in the SAD rats, increased the expression of c-Fos protein in the paraventricular nucleus, rostral ventrolateral medulla, and medial and inferior vestibular nuclei. The acute hypotension induced by SNP in a unilateral labyrinthectomy, with SAD, increased the expression of c-Fos protein in the contralesional vestibular nuclear complex, but decreased its expression in the ipsilesional vestibular nuclear complex. The acute hypotension induced by SNP in a bilateral labyrinthectomy, with SAD, showed only slight expression of c-Fos protein in the bilateral vestibular nuclear complex. CONCLUSION: These results suggest that the acute hypotension induced by SNP activates the vestibular nuclear neurons by decreasing the blood flow in the peripheral vestibular receptors, and that these in turn modulate blood pressure through activation of the catecholaminergic nervous system and neuroendocrine reflex.
Animals ; Baroreflex ; Blood Pressure* ; Hypotension ; Locomotion ; Nervous System ; Neurons ; Nitroprusside ; Paraventricular Hypothalamic Nucleus ; Pressoreceptors ; Rats* ; Reflex ; Respiration ; Solitary Nucleus ; Supraoptic Nucleus ; Vestibular Nuclei

The purpose of this study is to investigate the antinociceptive effects of ginsenosides on toothache. c-Fos immunoreactive (IR) neurons were examined after noxious intrapulpal stimulation (NS) by intrapulpal injection of 2 M KCl into upper and lower incisor pulps exposed by bone cutter in Sprague Dawley rats. The number of Fos-IR neurons was increased in the trigeminal subnucleus caudalis (Vc) and the transitional region between Vc and subnucleus interpolaris (Vi) by NS to tooth. The intradental NS raised arterial blood pressure (BP) and heart rate (HR). The number of Fos-IR neurons was also enhanced in thalamic ventral posteromedial nucleus (VPMN) and centrolateral nucleus (CLN) by NS to tooth. The intradental NS increased the number of Fos-IR neurons in the nucleus tractus solitarius (NTS) and rostral ventrolateral medulla (RVLM), hypothalamic supraoptic nucleus (SON) and paraventricular nucleus (PVN), central cardiovascular regulation centers. Ginsenosides reduced the number of c-Fos-IR increased by NS to tooth in the trigeminal Vc and thalamic VPMN and CLN. Naloxone, an opioid antagonist, did not block the effect of ginsenoside on the number of Fos-IR neurons enhanced by NS to tooth in the trigeminal Vc and thalamic VPMN and CLN. Ginsenosides ameliorated arterial BP and HR raised by NS to tooth and reduced the number of Fos-IR neurons increased by NS to tooth in the NTS, RVLM, hypothalamic SON, and PVN. These results suggest that ginsenosides have an antinociceptive effect on toothache through non-opioid system and attenuates BP and HR increased by NS to tooth.
Animals ; Arterial Pressure ; Brain ; Ginsenosides ; Heart Rate ; Incisor ; Naloxone ; Neurons ; Paraventricular Hypothalamic Nucleus ; Rats ; Rats, Sprague-Dawley ; Solitary Nucleus ; Supraoptic Nucleus ; Tooth ; Toothache ; Ventral Thalamic Nuclei

The present study was aimed to explore the effects of intraperitoneal injection of growth hormone releasing peptide-6 (GHRP-6), a ghrelin receptor agonist, on food intake and neuronal activity of feeding-related nuclei in the hypothalamus of NMRI mice. Accumulated amount of food intake was measured, and total number of c-fos immunoreactive neurons in arcuate nucleus (ARC), paraventricular nucleus (PVN) and supraoptic nucleus (SON) was counted by immunohistochemistry at 1, 3 and 6 h after the GHRP-6 injection. The results showed that GHRP-6 significantly increased the amount of food intake with a peak at 3 h after the GHRP-6 injection. Meanwhile, GHRP-6 could promote c-fos expression in the ARC and PVN independent of food intake, and the total number of c-fos immunoreactive neurons was peaked at 1 h after injection and then decreased gradually. These results suggest that GHRP-6 may increase food intake in time-dependent manner, which is associated with up-regulations of c-fos protein expression in the ARC and PVN.
Animals ; Arcuate Nucleus of Hypothalamus ; Eating ; Immunohistochemistry ; Male ; Mice ; Neurons ; Oligopeptides ; Paraventricular Hypothalamic Nucleus ; Proto-Oncogene Proteins c-fos ; Receptors, Ghrelin ; Supraoptic Nucleus