Urocortin1-induced anorexia is regulated by activation of the serotonin 2C receptor in the brain

AbstractThis study was conducted to determine the mechanisms by which serotonin (5-hydroxytryptamine, 5-HT) receptors are involved in the suppression of food intake in a rat stress model and to observe the degree of activation in the areas of the brain involved in feeding. In the stress model, male Sprague–Dawley rats (8 weeks old) were given intracerebroventricular injections of urocortin (UCN) 1. To determine the role of the 5-HT2c receptor (5-HT2cR) in the decreased food intake in UCN1-treated rats, specific 5-HT2cR or 5-HT2b receptor (5-HT2bR) antagonists were administered. Food intake was markedly reduced in UCN1-injected rats compared with phosphate buffered saline treated control rats. Intraperitoneal administration of a 5-HT2cR antagonist, but not a 5-HT2bR antagonist, significantly inhibited the decreased food intake. To assess the involvement of neural activation, we tracked the expression of c-fos mRNA as a neuronal activation marker. Expression of the c-fos mRNA in the arcuate nucleus, ventromedial hypothalamic nucleus (VMH) and rostral ventrolateral medulla (RVLM) in UNC1-injected rats showed significantly higher expression than in the PBS-injected rats. Increased c-fos mRNA was also observed in the paraventricular nucleus (PVN), the nucleus of the solitary tract (NTS), and the amygdala (AMG) after injection of UCN1. Increased 5-HT2cR protein expression was also observed in several areas. However, increased coexpression of 5-HT2cR and c-fos was observed in the PVN, VMH, NTS, RVLM and AMG. Whereas, pro-opiomelanocortin mRNA expression was not changed. In an UNC1-induced stress model, 5-HT2cR expression and activation was found in brain areas involved in feeding control

Peripheral α2-β1 adrenergic interactions mediate the ghrelin response to brain urocortin 1 in rats

SummaryThe autonomic nervous system (ANS) conveys neuronal input from the brain to the stomach. We investigated mechanisms through which urocortin 1 (UCN1) injected intracerebroventricularly (ICV, 300pmol/rat) inhibits circulating ghrelin in rats. This was achieved by assessing (1) the induction of c-fos gene expression as a marker of neuronal activation in specific hypothalamic and caudal brainstem regulating ANS; (2) the influence of vagotomy and pharmacological blockade of central and peripheral α- and β-adrenergic receptor (AR) on ICV UCN1-induced reduction of plasma ghrelin levels (determined by ELISA); and (3) the relevance of this pathway in the feeding response to a fast in rats. UCN1 increased c-fos mRNA expression in key brain sites influencing sympathetic activity namely the hypothalamic paraventricular and ventromedial nuclei, locus coeruleus, nucleus of the solitary tract, and rostral ventrolateral medulla, by 16-, 29-, 6-, 37-, and 13-fold, respectively. In contrast, the dorsal motor nucleus of the vagus had little c-fos mRNA expression and ICV UCN1 induced a similar reduction in acylated ghrelin in the sham-operated (31%) and vagotomized (41%) rats. An intraperitoneal (IP) injection of either a non-selective α- or selective α2-AR antagonist reduced, while a selective α2-AR agonist enhanced ICV UCN1-induced suppression of plasma acylated ghrelin levels. In addition, IP injection of a non-selective β- or selective β1-AR agonist blocked, and selective β1-AR antagonist augmented, the ghrelin response to ICV UCN1. The IP injections of a selective α1- or non-selective β or β2-AR antagonists, or any of the pretreatments given ICV had no effect. ICV UCN1 reduced the 2-h food intake in response to a fast by 80%, and this effect was partially prevented by a selective α2-AR antagonist. These data suggest that ICV UCN1 reduces plasma ghrelin mainly through the brain sympathetic component of the ANS and peripheral AR specifically α2-AR activation and inactivation of β1-AR. The α2-AR pathway contributes to the associated reduction in food intake

Advantages and Disadvantages of Hyperbaric Oxygen Treatment in Mice with Obesity Hyperlipidemia and Steatohepatitis

The effect of hyperbaric oxygen treatment (HBOT) was examined using MSG mice, which are an animal model of obesity, hyperlipidemia, diabetes, and nonalcoholic fatty liver disease. Nineteen MSG male mice were divided into HBOT treated and control groups at 12 weeks of ages. The HBOT group was treated with hyperbaric oxygen from 12 to 14 weeks (first phase) and then from 16 to 18 weeks (second phase). Interestingly, the body weight of the HBOT group was significantly lower (P < 0.01) than that of the control group. In contrast, the serum lipid level did not show significant changes between the two groups. As for the effects of increasing oxidative stress, the liver histology of the HBOT group showed severer cellular damage and aberrant TNF-α expression. HBOT has the advantage of improving obesity in patients with metabolic syndrome, but the fault of causing organ damage by increasing oxidative stress

Suppression of Propionibacterium acnes

Purpose. Macrophages serve as sweepers of microbes and inflammation-derived wastes and regulators of inflammation. Some traditional Japanese medicines are reported to have adjuvant effects by modifying macrophages. Our aim was to characterize the actions of jumihaidokuto (JHT) for treatment of skin inflammations including acne vulgaris, in which Propionibacterium acnes has pathogenic roles. Methods. Dermatitis was induced in rat ears by intradermal injection of P. acnes. JHT or prednisolone (PDN) was given orally, and ear thickness and histology were evaluated. The effects of constituents and metabolites of JHT on monocytes were tested by cell-based assays using the human monocytic THP-1 cell. Results. JHT and PDN suppressed the ear thickness induced by P. acnes injection. Histological examinations revealed that JHT, but not PDN, promoted macrophage accumulation at 24 h after the injection. PDN suppressed the macrophage chemokine MCP-1 in the inflamed ears, while JHT did not affect it. The JHT constituents liquiritigenin and isoliquiritin increased expression of CD86 (type-1 macrophage marker) and CD192 (MCP-1 receptor) and enhanced phagocytosis by THP-1. Conclusions. JHT suppressed dermatitis, probably by enhancing type-1 macrophage functions, with an action different from PDN. JHT may be a beneficial drug in treatment of skin inflammation induced by P. acnes

Preventive Effects of Salacia reticulata on Obesity and Metabolic Disorders in TSOD Mice

The extracts of Salacia reticulata (Salacia extract), a plant that has been used for the treatment of early diabetes, rheumatism and gonorrhea in Ayurveda, have been shown to have an anti-obesity effect and suppress hyperglycemia. In this study, the effects of Salacia extract on various symptoms of metabolic disorder were investigated and compared using these TSOD mice and non-obese TSNO mice. Body weight, food intake, plasma biochemistry, visceral and subcutaneous fat (X-ray and CT), glucose tolerance, blood pressure and pain tolerance were measured, and histopathological examination of the liver was carried out. A significant dose-dependent decline in the gain in body weight, accumulation of visceral and subcutaneous fat and an improvement of abnormal glucose tolerance, hypertension and peripheral neuropathy were noticed in TSOD mice. In addition, hepatocellular swelling, fatty degeneration of hepatocytes, inflammatory cell infiltration and single-cell necrosis were observed on histopathological examination of the liver in TSOD mice. Salacia extract markedly improved these symptoms upon treatment. Based on the above results, it is concluded that Salacia extract has remarkable potential to prevent obesity and associated metabolic disorders including the development of metabolic syndrome

Effects of Long-Term Administration of Gardeniae Fructus on Intra-Abdominal Organs of Rats

Many recent reports have suggested a possible association between Japanese traditional (Kampo) medicines containing Gardeniae Fructus (GF, the fruit of Gardenia jasminoides J. Ellis) and the mesenteric phlebosclerosis (MP). MP is a chronic orphan disease characterized by venous calcification extending from the colonic wall to the mesentery, usually developing in the proximal colon. In the present study, we administered GF to Wistar/ST female rats as 1% and 2% feed in the diet for 11 months to evaluate any calcification and/or fibrosis of veins in the colonic wall and mesentery. The reversibility of GF’s effects was examined by feeding a normal diet for an additional 3 months. A significant decrease in body weight gain and food consumption occurred in the 2% GF group. Pigmentation of the liver, kidney, and spleen in macroscopic or histopathological examination was observed after 11-month administration, which disappeared after the 3-month recovery period. Histopathological findings such as fibrous thickening and calcification of vein walls, characteristic of human MP, were not observed. Fibrosis in the colonic lamina propria was observed in the 2% GF group but not in the 1% GF group during the treatment period, but the incidence as well as grade of this type of fibrosis decreased in the recovery period, suggesting that the effects of GF were reversible. In the present study, chronic GF administration did not result in any venous pathological changes but induced pigmentation in the liver, kidneys, and spleen and moderate fibrosis in the colonic lamina propria, all of which being reversible. Further studies are required to determine the association between GF and MP

Vulnerability to psychological stress-induced anorexia in female mice depends on blockade of ghrelin signal in nucleus tractus solitarius

Background and Purpose Women have a higher incidence of eating disorders than men. We investigated whether the effects of ghrelin on feeding are affected by sex and stress, and to elucidate the mechanisms that may cause sex differences in stress-mediated anorexia, focusing on ghrelin. Experimental Approach Acylated ghrelin was administered to naive and psychologically stressed male and female C57BL/6J mice, followed by measurements of food intake and plasma hormone levels. Ovariectomy was performed to determine the effects of ovary-derived oestrogen on stress-induced eating disorders in female mice. The numbers ofAgrporc-FosmRNA-positive cells and estrogen receptor alpha/c-Fos protein-double-positive cells were assessed. Key Results Ghrelin administration to naive female mice caused a higher increase in food intake, growth hormone secretion,AgrpmRNA expression in the arcuate nucleus andc-Fosexpression in the nucleus tractus solitarius (NTS) than in male mice. In contrast, psychological stress caused a more sustained reduction in food intake in females than males. The high sensitivity of naive females to exogenous ghrelin was attenuated by stress exposure. The stress-induced decline in food intake was not abolished by ovariectomy. Estrogen receptor-alpha but not -beta antagonism prevented the decrease in food intake under stress. Estrogen receptor-alpha/c-Fos-double-positive cells in the NTS were significantly increased by stress only in females. Conclusion and Implications Stress-mediated eating disorders in females may be due to blockade of ghrelin signalling via estrogen receptor-alpha activation in the NTS. Targeting the ghrelin signal in the brain could be a new treatment strategy to prevent these disorders