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Hristov M, Landzhov B, Yakimova K. Effect of leptin on nitrergic neurons in the lateral hypothalamic area and the supraoptic nucleus of rats. Biotech Histochem 2024; 99:125-133. [PMID: 38533595 DOI: 10.1080/10520295.2024.2335167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024] Open
Abstract
The adipocyte-derived hormone, leptin, plays a key role in the maintenance of energy homeostasis. Leptin binds to the long form of its receptor, which is predominantly expressed in various hypothalamic regions, including the lateral hypothalamic area (LH) and supraoptic nucleus (SO). Several studies have suggested that leptin directly activates neuronal nitric oxide synthase, leading to increased nitric oxide production. We used histochemistry for nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) as a marker for nitric oxide synthase activity and assessed the effect of leptin on nitrergic neurons in the LH and SO of rats. We found that intraperitoneal administration of leptin led to a significant increase in the number of NADPH-d-positive neurons in the LH and SO. In addition, the intensity (optical density) of NADPH-d staining in LH and SO neurons was significantly elevated in rats that received leptin compared with saline-treated rats. These findings suggest that nitrergic neurons in the LH and SO may be implicated in mediating the central effects of leptin.
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Affiliation(s)
- Milen Hristov
- Department of Pharmacology and Toxicology, Faculty of Medicine, Medical University of Sofia, Sofia, Bulgaria
| | - Boycho Landzhov
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, Medical University of Sofia, Sofia, Bulgaria
| | - Krassimira Yakimova
- Department of Pharmacology and Toxicology, Faculty of Medicine, Medical University of Sofia, Sofia, Bulgaria
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Hristov M, Landzhov B, Yakimova K. Cafeteria diet-induced obesity reduces leptin-stimulated NADPH-diaphorase reactivity in the hypothalamic arcuate nucleus of rats. Acta Histochem 2020; 122:151616. [PMID: 33066838 DOI: 10.1016/j.acthis.2020.151616] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 08/08/2020] [Accepted: 08/17/2020] [Indexed: 02/07/2023]
Abstract
Leptin is an adipokine that plays an important role in the regulation of energy homeostasis. The failure of endogenous and exogenous leptin to mediate its effects (for example, at suppressing appetite and decreasing body weight) has been termed leptin resistance. Hyperleptinemia and leptin resistance can be well demonstrated in animals in which obesity is induced by consumption of a palatable, high-calorie diet (e.g., cafeteria diet-induced obesity). Since leptin receptor signaling is known to be impaired in the hypothalamic arcuate nucleus (ARC) of obese rodents, we investigated the effect of leptin on nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) reactivity in the ARC of male Wistar rats with cafeteria diet-induced obesity. Our results have shown that after intraperitoneal administration of leptin, the number of NADPH-d positive neurons in the ARC was significantly lower in obese rats compared with that observed in normal weight rats. Additionally, we have found that leptin-induced NADPH-d staining in ARC neurons and the adjacent ependyma was decreased in obese rats. The results presented here suggest that the ability of leptin to activate nitric oxide synthase in neurons within the ARC as well as tanycytes and ependymal cells of the third ventricle is reduced in rats made obese by a cafeteria diet. We speculate that impairment in leptin-induced NO production presents a potential mechanism, involved in the pathogenesis of obesity and obesity-related disease states.
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Affiliation(s)
- Milen Hristov
- Department of Pharmacology and Toxicology, Faculty of Medicine, Medical University of Sofia, 2 "Zdrave" St., 1431 Sofia, Bulgaria.
| | - Boycho Landzhov
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, Medical University of Sofia, 2 "Zdrave" St., 1431 Sofia, Bulgaria
| | - Krassimira Yakimova
- Department of Pharmacology and Toxicology, Faculty of Medicine, Medical University of Sofia, 2 "Zdrave" St., 1431 Sofia, Bulgaria
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3
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Increased NADPH-diaphorase reactivity in the hypothalamic paraventricular nucleus and tanycytes following systemic administration of leptin in rats. Acta Histochem 2019; 121:690-694. [PMID: 31227177 DOI: 10.1016/j.acthis.2019.06.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/11/2019] [Accepted: 06/13/2019] [Indexed: 12/25/2022]
Abstract
Leptin, a hormone mainly produced by adipocytes in proportion to fat mass, is a key component in the regulation of energy homeostasis and reproductive, neuroendocrine, immune, and metabolic functions. Leptin binds to the leptin receptor, which is expressed throughout the central nervous system but particularly in neurons of several nuclei of the hypothalamus, such as the arcuate nucleus (ARC) and paraventricular nucleus (PVN). It has been found that nitric oxide (NO) plays an important role in mediating effects of leptin. Since PVN and ARC neurons are known to express leptin receptors, we investigated the effects of leptin on nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) reactivity in the PVN and ARC of male Wistar rats. Our results have shown that systemic administration of leptin resulted in increased NADPH-d positive cell number in the PVN and ARC, suggesting that both the PVN and ARC may be important centers in the hypothalamus for the leptin action, mediated by increased NO production. In addition, we have also observed that hypothalamic tanycytes in the ventral portion of the third ventricle were NADPH-d positive. We speculate that leptin may affect the release of neurohormones and hypothalamic neurogenesis by activating nitric oxide synthase in hypothalamic tanycytes.
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Marcelino AA, Moura AS, Barradas PC, Tenório F. Hypothalamic Nuclei Nitric Oxide Synthase Expression in Rats Malnourished During Early Lactation Period. Nutr Neurosci 2013; 7:177-84. [PMID: 15526992 DOI: 10.1080/10284150412331279809] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In humans and other animals, it has been shown that protein malnutrition during the prenatal period leads to permanent changes, which in adulthood may cause chronic diseases. Molecules involved in the control of energy metabolism could be targets to alterations caused by nutritional status. Some hypothalamic nuclei as the paraventricular (PVN), ventro-medial and arcuate are related to energy metabolism regulation. Orexigenic and anorexigenic molecules are involved in this regulation. Some studies have showed that these nuclei present nitric oxide synthase (NOS) and that it is increased in obese rats. Recently it had been shown that rats malnourished during the lactation period presented metabolic alterations that persist in adulthood. The aim of this work was to study the expression of NOS in hypothalamic nuclei of rats submitted to malnutrition during the early lactation period. Rats from post-natal day (P10) to P90 were used. Control dams were fed with regular chow pellets and diet dams were fed with protein-free chow pellets during the first 10 days of lactation. NADPH-diaphorase or immunostaining techniques were used to access NOS expression in hypothalamic nuclei. Our results show a delay in NOS expression in the PVN and VMH of malnourished rats. It may affect the development of the hypothalamic circuitry, leading to a metabolic imprinting.
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Affiliation(s)
- A A Marcelino
- Departamento de Farmacologia e Psicobiologia, Instituto de Biologia Roberto Alcântara Gomes, Universidade do Estado do Rio de Janeiro, Av. 28 de setembro, 87, fds, 5 andar, 20551-030 Rio de Janeiro, RJ, Brasil
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5
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Rocha-de-Melo AP, Picanço-Diniz CW, Borba JMC, Santos-Monteiro J, Guedes RCA. NADPH-diaphorase Histochemical Labeling Patterns in the Hippocampal Neuropil and Visual Cortical Neurons in Weaned Rats Reared during Lactation on Different Litter Sizes. Nutr Neurosci 2013; 7:207-16. [PMID: 15682647 DOI: 10.1080/10284150400001961] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Tissue distribution of nitric oxide-synthases was investigated in the rat hippocampus and visual cortex under nutritional changes induced by modification of the litter size. Young (30-45-days-old) rats, suckled in litters formed by 3,6 or 12 pups (called small, medium and large litters, respectively), were studied by using nicotine-adenine-dinucleotide phosphate-diaphorase histochemistry (shortly, diaphorase), a simple and robust procedure to characterize tissue distribution of nitric oxide-synthases. We assessed morphometric features of the diaphorase-positive cells in visual cortex, and the neuropil histochemical activity in hippocampal CA1 and dentate gyrus using densitometry analysis. In the large-litter group, the labeled-cell density in white matter of area 17 was higher, as compared to the small-litter group. There was a clear trend, in the large-litter group, to lower values of soma area, dendritic field and branches per neuron, but the differences were not significant. Densitometry analysis of hippocampus revealed a significant increase in the relative neuropil histochemical activity of the dentate gyrus molecular layer in the larger litters, which may be associated to increased compensatory blood flow in the hippocampus. The pathophysiological mechanisms of the observed changes remain to be investigated.
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Affiliation(s)
- Ana Paula Rocha-de-Melo
- Departamento de Nutrição, Universidade Federal de Pernambuco, BR-50670-901, Recife, PE, Brazil
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6
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Hong MS, Song JY, Yun DH, Cho JJ, Chung JH. Increase of NADPH-diaphorase expression in hypothalamus of stat4 knockout mice. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2009; 13:337-41. [PMID: 19915694 DOI: 10.4196/kjpp.2009.13.5.337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Revised: 10/09/2009] [Accepted: 10/19/2009] [Indexed: 11/15/2022]
Abstract
Signal transducer and activator of transcription 4 (STAT4), a STAT family member, mediates interleukin 12 (IL12) signal transduction. IL12 is known to be related to calorie-restricted status. In the central nervous system, IL12 also enhances the production of nitric oxide (NO), which regulates food intake. In this study, the expression of neuronal NO synthase (Nos1), which is also related to food intake, was investigated in the hypothalamic areas of Stat4 knockout (KO) mice using nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry, a marker for neurons expressing Nos1 enzyme. Western blots were also performed to evaluate Nos1 and Fos expression. Wild-type Balb/c (WT group, n=10 male) and Stat4 KO mice (Stat4 KO group, n=8 male) were used. The body weight and daily food intake in the WT group were 22.4+/-0.3 and 4.4 g per day, while those in the Stat4 KO group were 18.7+/-0.4 and 1.8 g per day, respectively. Stat4 mice had lower body weight and food intake than Balb/c mice. Optical intensities of NADPH-d-positive neurons in the paraventricular nucleus (PVN) and lateral hypothalamic area (LHA) of the Stat4 KO group were significantly higher than those of the WT group. Western blotting analysis revealed that the hypothalamic Nos1 and Fos expression of the Stat4 KO group was up-regulated, compared to that in the WT group. These results suggest that Stat4 may be related to the regulation of food intake and expression of Nos1 in the hypothalamus.
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Affiliation(s)
- Mee Sook Hong
- Kohwang Medical Research Institute, Kyung Hee University, Seoul 130-701, Korea
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7
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Lund TD, Hinds LR, Handa RJ. The androgen 5alpha-dihydrotestosterone and its metabolite 5alpha-androstan-3beta, 17beta-diol inhibit the hypothalamo-pituitary-adrenal response to stress by acting through estrogen receptor beta-expressing neurons in the hypothalamus. J Neurosci 2006; 26:1448-56. [PMID: 16452668 PMCID: PMC6675494 DOI: 10.1523/jneurosci.3777-05.2006] [Citation(s) in RCA: 194] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Estrogen receptor beta (ERbeta) and androgen receptor (AR) are found in high levels within populations of neurons in the hypothalamus. To determine whether AR or ERbeta plays a role in regulating hypothalamo-pituitary-adrenal (HPA) axis function by direct action on these neurons, we examined the effects of central implants of 17beta-estradiol (E2), 5alpha-dihydrotestosterone (DHT), the DHT metabolite 5alpha-androstan-3beta, 17beta-diol (3beta-diol), and several ER subtype-selective agonists on the corticosterone and adrenocorticotropin (ACTH) response to immobilization stress. In addition, activation of neurons in the paraventricular nucleus (PVN) was monitored by examining c-fos mRNA expression. Pellets containing these compounds were stereotaxically implanted near the PVN of gonadectomized male rats. Seven days later, animals were killed directly from their home cage (nonstressed) or were restrained for 30 min (stressed) before they were killed. Compared with controls, E2 and the ERalpha-selective agonists moxestrol and propyl-pyrazole-triol significantly increased the stress induced release of corticosterone and ACTH. In contrast, central administration of DHT, 3beta-diol, and the ERbeta-selective compound diarylpropionitrile significantly decreased the corticosterone and ACTH response to immobilization. Cotreatment with the ER antagonist tamoxifen completely blocked the effects of 3beta-diol and partially blocked the effect of DHT, whereas the AR antagonist flutamide had no effect. Moreover, DHT, 3beta-diol, and diarylpropionitrile treatment significantly decreased restraint-induced c-fos mRNA expression in the PVN. Together, these studies indicate that the inhibitory effects of DHT on HPA axis activity may be in part mediated via its conversion to 3beta-diol and subsequent binding to ERbeta.
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Affiliation(s)
- Trent D Lund
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523, USA.
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Kim MJ, Kim YO, Chang UJ, Kim HK, Chung JH, Oh DJ, Kim JW. Melatonin enhances NADPH-diaphorase activities in the hypothalamus of maternally-separated rats. Neurosci Lett 2005; 394:111-6. [PMID: 16297549 DOI: 10.1016/j.neulet.2005.10.038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2005] [Revised: 09/22/2005] [Accepted: 10/07/2005] [Indexed: 10/25/2022]
Abstract
Maternal separation or social isolation is a risk factor in the development of mammalian species affecting both physical and mental growth, and food intake regulation. Melatonin has been known to regulate body weight on various species including rodents. We investigated the effect of melatonin treatment on the expression of nitric oxide synthase, which may involved in food intake regulation, in the brain of maternally separated-rats using nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry. Melatonin (10 mg/kg i.p.) was injected to 14-day-old maternally-separated rats for 7 days. Maternally-separated rats with melatonin administration showed significantly higher staining intensities of NADPH-d-positive neurons in the paraventricular nucleus (PVN) and in lateral hypothalamic area (LHA) than maternally-separated without melatonin administration (P < 0.05). Body weight of melatonin treated rats significantly increased at the 6th and 7th day compared to that of rats without melatonin treatment (P < 0.05). These results indicate that melatonin may be associated with increase body weight via NOS in the hypothalamic areas in maternally-separated or socially isolated rats.
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Affiliation(s)
- Mi-Ja Kim
- Department of Obesity Management, Graduate School of Obesity Science Dongduk Women's University, Seoul, South Korea
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9
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Iuras A, Telles MM, Bertoncini CRA, Ko GM, de Andrade IS, Silveira VLF, Ribeiro EB. Central administration of a nitric oxide precursor abolishes both the hypothalamic serotonin release and the hypophagia induced by interleukin-1beta in obese Zucker rats. ACTA ACUST UNITED AC 2005; 124:145-50. [PMID: 15544852 DOI: 10.1016/j.regpep.2004.07.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2004] [Accepted: 07/02/2004] [Indexed: 01/23/2023]
Abstract
Serotonin-induced anorexia has long been recognized as an important part of the CNS mechanisms controlling energy balance. More recently, interleukin-1beta and nitric oxide have been suggested to influence this control, possibly through modulation of hypothalamic serotonin. The present work aimed at investigating the interaction of these systems. We addressed whether 5-HT is affected during IL-1beta-induced anorexia in obese Zucker rats and the influence of the central NO system on this IL-1beta/5-HT interaction. Using microdialysis, we observed that an intracerebroventricular injection of 10 ng IL-1beta significantly stimulated 5-HT extracellular levels in the VMH, with a peak variation of 102+/-41% above baseline. IL-1beta also significantly reduced the 4-h feeding by 33% and the 24-h feeding by 42%. Contrarily, these effects were absent when IL-1beta was injected 2 h after the i.c.v. administration of 20 microg of the NO precursor L-arginine. The results suggest that, in obese Zucker rats, activation of the serotonergic system in the medial hypothalamus participates in IL-1beta-induced anorexia. Since L-arginine, probably through NO stimulation, abolished both the anorexia and the serotonergic activation, it can be proposed that the NO system, either directly or indirectly, counteracts IL-1beta anorexia. The hypothalamic serotonergic system is likely to mediate this NO effect.
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Affiliation(s)
- Anderson Iuras
- Department of Physiology, Federal University of São Paulo, Rua Botucatu, 862-2 Andar, Vila Clementino, São Paulo, SP 04023-060, Brazil
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Yao ST, Gouraud S, Paton JFR, Murphy D. Water deprivation increases the expression of neuronal nitric oxide synthase (nNOS) but not orexin-A in the lateral hypothalamic area of the rat. J Comp Neurol 2005; 490:180-93. [PMID: 16052497 DOI: 10.1002/cne.20662] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The discovery that the lateral hypothalamic area (LHA) might be important in modulating drinking behavior and fluid balance has led to numerous studies aimed at identifying the key neurotransmitters/neuromodulators and pathways involved. While past studies have demonstrated the presence of neuronal nitric oxide synthase (nNOS) within the LHA, its role in the regulation of fluid homeostasis is not known. In light of this, and the mounting evidence suggesting a role for nitric oxide in osmotic regulation within the hypothalamus, this study sought to determine the effects of 24- and 72-hours of water deprivation on nNOS protein expression within the LHA of the rat with immunohistochemistry. In euhydrated control animals we observed nNOS-like immunoreactivity throughout all levels of the LHA. Following 24 hours of dehydration the number of nNOS-like immunopositive neurons was significantly increased in the rostral but not the caudal regions of LHA. Seventy-two hours of water deprivation lead to further increases in nNOS-like immunoreactivity at different levels of the LHA. Interestingly, however, we observed increased nNOS-like immunoreactivity in the caudal regions of the LHA that was not evident after 24 hours of water deprivation. Double-labeling immunofluorescence histochemistry revealed that the nNOS-like immunoreactive neurons were not colocalized with the orexin-A-containing neurons. These results suggest that an osmotic challenge leads to an upregulation of nNOS immunoreactivity within discrete areas of the LHA. This altered neurochemistry within the LHA further highlights the potential importance of nitric oxide and the LHA in central regulation of fluid homeostasis.
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Affiliation(s)
- Song T Yao
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, UK.
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11
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Sadler CJ, Wilding JPH. Reduced ventromedial hypothalamic neuronal nitric oxide synthase and increased sensitivity to NOS inhibition in dietary obese rats: further evidence of a role for nitric oxide in the regulation of energy balance. Brain Res 2004; 1016:222-8. [PMID: 15246858 DOI: 10.1016/j.brainres.2004.05.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2004] [Indexed: 11/25/2022]
Abstract
Inhibition of hypothalamic nitric oxide (NO) decreases energy intake, and changes in hypothalamic NO synthase (NOS) have been observed in genetically obese rodents, but it is not known if NO is involved in the development of diet-induced obesity (DIO). We therefore measured changes in hypothalamic neuronal NOS (nNOS) in DIO and investigated effects of peripheral and central inhibition of NOS in this model. Expression of nNOS in relation to changes in nutritional state was measured by immunohistochemistry, with radiochemical detection. The effect of chronic intraperitoneal (i.p.) administration of the NOS inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME, 50 mg/kg/day) on energy intake, bodyweight and hypothalamic nitric oxide content was assessed in both chow-fed and DIO animals. Twenty-four hour energy intake after acute intracerebroventricular (i.c.v.) of L-NAME was also measured. Diet-induced obese animals had a statistically significant 32% reduction in the number of nNOS-immunolabelled cells in the ventromedial hypothalamus compared to chow-fed controls. Intraperitoneal administration of L-NAME decreased hypothalamic NO content in both chow-fed and DIO. Energy intake was reduced by 16% in DIO over 16 days, whereas energy intake was only reduced by 11% in chow-fed animals, although both were statistically significant. L-NAME significantly reduced body weight gain in DIO but not in chow-fed rats. L-NAME administered i.c.v. decreased 24 h energy intake to a greater extent in DIO rats, by 18%, compared with a 10% reduction in chow-fed rats. Ventromedial hypothalamic expression of nNOS is sensitive to changes in nutritional state. Despite having reduced nNOS, dietary obese rats were more sensitive to the effects of NOS inhibition than lean controls, suggesting a role for NO in the development of hyperphagia and obesity in rats fed a palatable diet.
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Affiliation(s)
- C J Sadler
- Neuroendocrine and Obesity Biology Unit, Department of Medicine, University of Liverpool, Liverpool L69 3GA, UK
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Kino M, Yamato T, Aomine M. Simultaneous measurement of nitric oxide, blood glucose, and monoamines in the hippocampus of diabetic rat: an in vivo microdialysis study. Neurochem Int 2004; 44:65-73. [PMID: 12971908 DOI: 10.1016/s0197-0186(03)00125-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The present study was undertaken to examine the relationships among the levels of nitric oxide (NO), monoamines, and blood glucose in the diabetic hippocampus. The levels of NO and monoamines (serotonin, 5-hydroxytryptamine [5-HT] and dopamine [DA]) were simultaneously measured in several experiments, using in vivo microdialysis techniques. We used both experimentally and spontaneously diabetic rats as the diabetic animal model, and compared the findings with those obtained from non-diabetic rats. The effects of the changed level of blood glucose due to insulin administration on the levels of NO, 5-HT, and DA were assessed. Total NO metabolite levels (NOx) were calculated as the sum of nitrite (NO2-) and nitrate (NO3-) levels. The results in the present study showed that: (1) the plasma levels of NOx in both diabetic rats were low compared to those in control rats, (2) the hippocampal NOx levels in both diabetic rats were almost the same as those in control rats, while the levels of 5-HT and DA were low in the diabetics, and (3) a sudden decrease in the plasma glucose level due to insulin administration reduced the NOx level as well as enhanced the 5-HT level in the diabetic hippocampus, a finding consistent with the results of 7 days administration of insulin. Taken together, these findings suggest that changes in the plasma glucose level cause, at least in part, the changes in the levels of NOx and monoamines in the diabetic brain.
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Affiliation(s)
- Mayuko Kino
- Laboratory of Nutritional Physiology, Department of Nutrition Sciences, Faculty of Nutrition Sciences, Nakamura Gakuen University, 5-7-1 Befu, Jonan-ku, Fukuoka 814-0198, Japan
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13
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Cheng SB, Kuchiiwa S, Ren XQ, Gao HZ, Kuchiiwa T, Nakagawa S. Dioxin exposure down-regulates nitric oxide synthase and NADPH-diaphorase activities in the hypothalamus of Long-Evans rat. Neurosci Lett 2003; 345:5-8. [PMID: 12809975 DOI: 10.1016/s0304-3940(03)00347-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this study, we investigated the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) gastric administration on the expression of neuronal nitric oxide synthase (nNOS) and the NADPH-diaphorase (NADPH-d) activities in the brain of the Long-Evans rat. A single dose of TCDD (dissolved in olive oil, 50 microg/kg) or olive oil alone was administered to the rats by gavage. nNOS Western blotting experiment indicated a marked decrease in nNOS immunoreactivity at 1 and 2 weeks after TCDD treatment. NADPH-d histochemistry results showed a marked decrease in the number of NADPH-d stained cell bodies in the paraventricular hypothalamic nucleus, lateral hypothalamic area and perifornical nucleus in the TCDD-treated rats. The present study suggests that TCDD administration down-regulates nitric oxide product in the hypothalamus, which may be partially responsible for TCDD-induced feeding inhibition.
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Affiliation(s)
- Shi-Bin Cheng
- Department of Anatomy, Faculty of Medicine, Kagoshima University, Sakuragaoka 8-35-1, Japan
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14
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Cheng SB, Kuchiiwa S, Gao HZ, Kuchiiwa T, Nakagawa S. Morphological study of orexin neurons in the hypothalamus of the Long-Evans rat, with special reference to co-expression of orexin and NADPH-diaphorase or nitric oxide synthase activities. Neurosci Res 2003; 46:53-62. [PMID: 12725912 DOI: 10.1016/s0168-0102(03)00026-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Orexins, novel neuropeptides, are exclusively localized in the hypothalamus and implicated in the regulation of a variety of activities, including food intake and energy balance. Nitric oxide (NO), an unconventional neurotransmitter, is widely present in numerous brain regions including the hypothalamus, and has similar physiological roles to those of the orexins. The present study was undertaken to examine the distribution of orexin neurons and the presence of neuronal nitric oxide synthase (nNOS) in the orexin neurons to clarify whether NO interacts with the orexins in the neuronal regulation activities in the Long-Evans rat. We used two double-labeling methods: nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry in combination with orexin immunohistochemistry, and double-labeling fluorescent immunohistochemistry for orexin and nNOS. The majority of the orexin immunoreactive neurons were localized mainly in the areas of the dorsomedial hypothalamic nucleus (DMN), the dorsal part of the perifornical nucleus (PEF) and lateral hypothalamic area. The orexin immunoreactive cell bodies were medium in size, and triangular, round, elliptic, and fusiform in shape. The sizes and shapes of orexin neurons in the different parts were similar. Cell bodies coexpressing the orexin and nNOS or NADPH-d were present in the areas of the DMN and the PEF, and the nerve fibers containing orexin and nNOS were distributed in the DMN and PEF, arcuate nucleus (ARN) and ventromedial hypothalamic nucleus (VMH). These results provide morphological evidence that there exists a population of nNOS- or NADPH-d-/orexin-coexpressing neurons in the orexinergic cell group in the hypothalamus, and taken together with previous findings, suggest that NO may play a role in the mechanisms by which orexin neurons regulate food intake and energy balance.
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Affiliation(s)
- Shi-Bin Cheng
- Department of Anatomy, Faculty of Medicine, Kagoshima University, Sakuragaoka 8-35-1, Kagoshima 890-8520, Japan
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Jang MH, Kim H, Shin MC, Lim BV, Lee TH, Jung SB, Kim CJ, Kim EH. Administration of Folium mori extract decreases nitric oxide synthase expression in the hypothalamus of streptozotocin-induced diabetic rats. JAPANESE JOURNAL OF PHARMACOLOGY 2002; 90:189-92. [PMID: 12419890 DOI: 10.1254/jjp.90.189] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Folium mori, the leaves of Morus alba L., has traditionally been used for the treatment of diabetic hyperglycemia. It has been shown to induce enhanced NOS expression in the hypothalamus of rats with streptozotocin (STZ)-induced diabetes. In the present study, the effect of Folium mori on the expression of nitric oxide synthase (NOS) in the hypothalamus of STZ-induced diabetic rats was investigated via nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry. Enhanced NAPDH-d expression was detected in the paraventricular nucleus, ventromedial hypothalamic nucleus, and lateral hypothalamic area of the hypothalamus in the STZ-induced diabetes group. Administration of the aqueous extract of Folium mori to rats with STZ-induced diabetes resulted in decreased NADPH-d positivity. These results suggest that Folium mori treatment is effective in curbing the desire for food under diabetic conditions via modulation of NO expression in the hypothalamus.
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Affiliation(s)
- Mi-Hyeon Jang
- Department of Physiology, College of Medicine, Kyung Hee University, Seoul, Korea
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Jang MH, Shin MC, Lim BV, Chung JH, Kang HS, Kang SA, Choue RW, Kim EH, Kim CJ. Nicotine administration decreases nitric oxide synthase expression in the hypothalamus of food-deprived rats. Neurosci Lett 2002; 322:29-32. [PMID: 11958836 DOI: 10.1016/s0304-3940(02)00076-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Effect of nicotine on nitric oxide synthase (NOS) expression in various hypothalamic regions was investigated in rats via nicotineamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry. Sprague-Dawley rats were divided into the fed group, the fed and nicotine-treated group, the food-deprived group, and the food-deprived and nicotine-treated group. The fed groups received abundant food and water, while food was withheld from the food-deprived groups for 48 h. The nicotine-treated groups were injected with nicotine. Following food deprivation, enhanced NAPDH-d expression was detected in the paraventricular nucleus, ventromedial hypothalamic nucleus, and lateral hypothalamic area of the hypothalamus. Nicotine administration to the food-deprived rats resulted in decreased NADPH-d positivity. The present results indicate that nicotine administration is effective in limiting the enhancement in NOS expression following food restriction.
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Affiliation(s)
- Mi-Hyeon Jang
- Department of Physiology, College of Medicine, Kyung Hee University, 1 Hoigi-dong, Dongdaemun-gu, Seoul 130-701, South Korea
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