scholarly journals Arcuate NPY neurons and energy homeostasis in diet-induced obese and resistant rats

1999 ◽  
Vol 276 (2) ◽  
pp. R382-R387 ◽  
Author(s):  
Barry E. Levin
Keyword(s):  
Metabolic Regulation ◽  
Energy Homeostasis ◽  
Arcuate Nucleus ◽  
Inbred Strains ◽  
Energy Restriction ◽  
Short Term ◽  
Diet Induced Obesity ◽  
Body Weights ◽  
Hypothalamic Arcuate Nucleus

The neuropeptide Y (NPY) neurons in the hypothalamic arcuate nucleus regulate and are regulated by short-term changes in energy homeostasis. Both outbred and inbred strains of rats that develop diet-induced obesity (DIO) or are diet resistant (DR) when fed a diet relatively high in energy, fat, and sucrose content (HE diet) were used to study arcuate NPY mRNA expression during long-term changes in energy balance. Outbred, chow-fed obesity-prone rats had 59% higher NPY levels than obesity-resistant rats. After 14 wk on HE diet, DIO rats had 17% lower NPY levels than DR rats made comparably obese on a highly palatable diet. When switched to chow, obese DR rats spontaneously reduced their intake and their body weights fell to control levels in association with a 10% decrease in NPY levels. DIO rats lost weight only with energy restriction associated with a 21% increase in their NPY levels. When again fed ad libitum, the weight and NPY levels in the rats returned to those of unrestricted DIO rats. Chow-fed, inbred DIO rats weigh more and are fatter than age-matched inbred DR rats. As with outbred DIO rats fed the HE diet, inbred DIO rats had 20% lower NPY levels than DR rats. Thus preobese, outbred DIO rats have high levels of NPY message that are not susceptible to metabolic regulation. When obesity develops in both inbred and outbred rats, the levels of NPY mRNA fall but become responsive to alterations in energy availability.

scholarly journals Insulin potentiates the synchronous firing of arcuate nucleus Kiss1 neurons that protects against diet-induced obesity

2020 ◽  
Author(s):  
Jian Qiu ◽  
Todd L. Stincic ◽  
Martha A. Bosch ◽  
Ashley M. Connors ◽  
Stefanie Kaech Petrie ◽  
...  
Keyword(s):  
Energy Homeostasis ◽  
Arcuate Nucleus ◽  
Pubertal Development ◽  
Excitatory Postsynaptic Potential ◽  
Endoplasmic Reticulum Calcium ◽  
Calcium Sensing ◽  
Diet Induced Obesity ◽  
Synchronous Firing ◽  
Hypothalamic Arcuate Nucleus ◽  
Excitatory Drive

AbstractKisspeptin neurons in the hypothalamic arcuate nucleus (Kiss1ARH) co-express kisspeptin, neurokinin B, dynorphin and provide an episodic, excitatory drive to gonadotropin-releasing hormone (GnRH) neurons, which is critical for pubertal development and fertility. Previously, we showed that high frequency firing of Kiss1ARH neurons co-releases NKB and dynorphin onto neighboring Kiss1ARH neurons to generate a slow excitatory postsynaptic potential (EPSP) that entrains intermittent, synchronous firing of Kiss1ARH neurons (Qiu et al., 2016). Presently, we discovered that insulin significantly increased the amplitude of the slow EPSP, which we documented is mediated by TRPC5 channels, and augmented synchronous GCaMP6s ([Ca]i) oscillations in Kiss1ARH neurons. Deletion of the endoplasmic reticulum calcium-sensing protein stromal interaction molecule 1 in Kiss1ARH neurons amplified insulin’s actions and protected ovariectomized female mice from developing obesity and glucose intolerance with high-fat dieting. Therefore, insulin appears to be critical for facilitating synchronous firing of Kiss1ARH neurons and coordinating energy homeostasis with fertility.

Dysregulation of arcuate nucleus preproneuropeptide Y mRNA in diet-induced obese rats

1997 ◽  
Vol 272 (5) ◽  
pp. R1365-R1370 ◽  
Author(s):  
B. E. Levin ◽  
A. A. Dunn-Meynell
Keyword(s):  
Arcuate Nucleus ◽  
High Energy ◽  
Energy Restriction ◽  
Dopamine Turnover ◽  
Mrna Levels ◽  
Sprague Dawley ◽  
Diet Induced Obesity ◽  
Sprague Dawley Rats ◽  
Hypothalamic Arcuate Nucleus

Neuropeptide Y (NPY) neurons in the hypothalamic arcuate nucleus (ARC) produce metabolic and physiological effects that promote the development and maintenance of obesity. In turn, NPY metabolism in these neurons is inhibited by dopamine release. In this study, ARC prepro-NPY mRNA and ARC/median eminence (ME) dopamine turnover were assessed in chow-fed male Sprague-Dawley rats prone to develop diet-induced obesity (DIO) or to be diet resistant (DR) when fed a high-energy (HE) diet. By in situ hybridization, DIO-prone rats had 39% more ARC NPY mRNA expression than DR-prone rats under chow-fed conditions. DIO-prone rat ARC/ME dopamine levels were 14% higher, but dopamine half-life was 176% longer and turnover was 59% less than DR-prone rats. Neither a 48-h fast nor 50% energy intake restriction for 5 days affected the already increased ARC NPY mRNA levels in DIO-prone rats. Both manipulations increased NPY expression to the level of DIO-prone rats in DR-prone rats by 23 and 35%, respectively. Finally, when fed HE diet for 2 wk, neither DIO- nor DR-prone rats altered their ARC NPY expression despite the development of obesity and hyperinsulinemia in DIO rats. Thus DIO-prone rats overexpress and fail to regulate ARC NPY mRNA to energy restriction or hyperinsulinemia. This dysregulation is possibly secondary to reduced inhibition because of defective ARC/ME dopamine turnover. Both may be important predisposing factors in the development of DIO.

scholarly journals Identification of Sox2 and NeuN Double-Positive Cells in the Mouse Hypothalamic Arcuate Nucleus and Their Reduction in Number With Aging

2021 ◽  
Vol 12 ◽  
Author(s):  
Ayumu Sugiura ◽  
Tatsuhiro Shimizu ◽  
Takeshi Kameyama ◽  
Tomohiko Maruo ◽  
Shin Kedashiro ◽  
...  
Keyword(s):  
Stem Cells ◽  
High Fat Diet ◽  
Arcuate Nucleus ◽  
High Fat ◽  
Double Positive ◽  
Diet Induced Obesity ◽  
Hypothalamic Arcuate Nucleus ◽  
Hypothalamic Cells ◽  
Induced Changes ◽  
Insight Into

The hypothalamus plays a central role in homeostasis and aging. The hypothalamic arcuate nucleus (ARC) controls homeostasis of food intake and energy expenditure and retains adult neural stem cells (NSCs)/progenitor cells. Aging induces the loss of NSCs and the enhancement of inflammation, including the activation of glial cells in the ARC, but aging-associated alterations of the hypothalamic cells remain obscure. Here, we identified Sox2 and NeuN double-positive cells in a subpopulation of cells in the mouse ARC. These cells were reduced in number with aging, although NeuN-positive neuronal cells were unaltered in the total number. Diet-induced obesity mice fed with high-fat diet presented a similar hypothalamic alteration to aged mice. This study provides a new insight into aging-induced changes in the hypothalamus.

scholarly journals Possible role for mRNA stability in the ammonium-controlled regulation of nitrate reductase expression

1994 ◽  
Vol 297 (3) ◽  
pp. 561-565 ◽  
Author(s):  
A C Cannons ◽  
L C Pendleton
Keyword(s):  
Nitrate Reductase ◽  
Mrna Stability ◽  
Metabolic Regulation ◽  
Reductase Activity ◽  
State Level ◽  
Apparent Difference ◽  
Short Term ◽  
Cell Extracts ◽  
Significant Difference

Ammonium, or a metabolite of ammonium, represses the expression of nitrate reductase (NR) in Chlorella vulgaris. The removal of ammonium and addition of nitrate (induction) resulted in a rapid (20 min) peaked synthesis of NR mRNA. Nitrate reductase protein and activity increased at a much lower rate, reaching their maxima by 8 h. Ammonium added to nitrate-grown cells resulted in a dramatic decrease in NR mRNA from a steady-state level to undetectable levels within 15 min of ammonium addition. Nitrate reductase activity and protein levels decreased to 20% and 40% of initial levels respectively over 8 h. The half-life for NR mRNA under these conditions was estimated to be less than 5 min, compared with 120 min for NR protein. Such rapid decreases in NR mRNA suggested a degradation and/or cessation in NR mRNA transcription. No apparent difference in NR mRNA-specific RNAase activity of crude cell extracts (NR-induced or repressed) was observed. However, a significant difference in the susceptibility to degradation of NR mRNA from long-term nitrate-grown cells compared with the NR mRNA isolated from short-term induced cells (20 min in nitrate) was observed. NR mRNA isolated from long-term-nitrate-grown cells was completely degraded by RNAases in cell extracts under conditions in which the NR mRNA isolated from short-term induced cells was resistant to degradation. These results suggest that mRNA stability may be an important factor in the metabolic regulation of assimilatory nitrate reductase in Chlorella.

scholarly journals Chronic CNS oxytocin signaling preferentially induces fat loss in high-fat diet-fed rats by enhancing satiety responses and increasing lipid utilization

2016 ◽  
Vol 310 (7) ◽  
pp. R640-R658 ◽  
Author(s):  
James E. Blevins ◽  
Benjamin W. Thompson ◽  
Vishwanath T. Anekonda ◽  
Jacqueline M. Ho ◽  
James L. Graham ◽  
...  
Keyword(s):  
High Fat Diet ◽  
High Fat ◽  
Short Term ◽  
Satiety Response ◽  
Diet Induced Obesity ◽  
Sustained Reduction ◽  
Oxytocin Infusion ◽  
Term Administration ◽  
The Central Nervous System

Based largely on a number of short-term administration studies, growing evidence suggests that central oxytocin is important in the regulation of energy balance. The goal of the current work is to determine whether long-term third ventricular (3V) infusion of oxytocin into the central nervous system (CNS) is effective for obesity prevention and/or treatment in rat models. We found that chronic 3V oxytocin infusion between 21 and 26 days by osmotic minipumps both reduced weight gain associated with the progression of high-fat diet (HFD)-induced obesity and elicited a sustained reduction of fat mass with no decrease of lean mass in rats with established diet-induced obesity. We further demonstrated that these chronic oxytocin effects result from 1) maintenance of energy expenditure at preintervention levels despite ongoing weight loss, 2) a reduction in respiratory quotient, consistent with increased fat oxidation, and 3) an enhanced satiety response to cholecystokinin-8 and associated decrease of meal size. These weight-reducing effects persisted for approximately 10 days after termination of 3V oxytocin administration and occurred independently of whether sucrose was added to the HFD. We conclude that long-term 3V administration of oxytocin to rats can both prevent and treat diet-induced obesity.

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