scholarly journals Control of feeding by Piezo-mediated gut mechanosensation in Drosophila

Author(s):  
Soohong Min ◽  
Yangkyun Oh ◽  
Pushpa Verma ◽  
David Van Vactor ◽  
Greg S.B. Suh ◽  
...  

SUMMARYAcross animal species, meals are terminated after ingestion of large food volumes, yet underlying mechanosensory receptors have so far remained elusive. Here, we identify an essential role for Drosophila Piezo in volume-based control of meal size. We discover a rare population of fly neurons that express Piezo, innervate the anterior gut and crop (a food reservoir organ), and respond to tissue distension in a Piezo-dependent manner. Activating Piezo neurons decreases appetite, while Piezo knockout and Piezo neuron silencing cause gut bloating and increase both food consumption and body weight. These studies reveal that disrupting gut distension receptors changes feeding patterns, and identify a key role for Drosophila Piezo in internal organ mechanosensation.

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Soohong Min ◽  
Yangkyun Oh ◽  
Pushpa Verma ◽  
Samuel C Whitehead ◽  
Nilay Yapici ◽  
...  

Across animal species, meals are terminated after ingestion of large food volumes, yet underlying mechanosensory receptors have so far remained elusive. Here, we identify an essential role for Drosophila Piezo in volume-based control of meal size. We discover a rare population of fly neurons that express Piezo, innervate the anterior gut and crop (a food reservoir organ), and respond to tissue distension in a Piezo-dependent manner. Activating Piezo neurons decreases appetite, while Piezo knockout and Piezo neuron silencing cause gut bloating and increase both food consumption and body weight. These studies reveal that disrupting gut distension receptors changes feeding patterns, and identify a key role for Drosophila Piezo in internal organ mechanosensation.


2013 ◽  
Vol 305 (5) ◽  
pp. R499-R505 ◽  
Author(s):  
Hyun-Ju Kim ◽  
Eun-Young Park ◽  
Mi-Jeong Oh ◽  
Sung-Soo Park ◽  
Kyung-Ho Shin ◽  
...  

Administration of metformin is known to reduce both body weight and food intake. Although the hypothalamus is recognized as a critical regulator of energy balance and body weight, there is currently no evidence for an effect of metformin in the hypothalamus. Therefore, we sought to determine the central action of metformin on energy balance and body weight, as well as its potential involvement with key hypothalamic energy sensors, including adenosine monophosphate-activated protein kinase (AMPK) and S6 kinase (S6K). We used meal pattern analysis and a conditioned taste aversion (CTA) test and measured energy expenditure in C56BL/6 mice administered metformin (0, 7.5, 15, or 30 μg) into the third ventricle (I3V). Furthermore, we I3V-administered either control or metformin (30 μg) and compared the phosphorylation of AMPK and S6K in the mouse mediobasal hypothalamus. Compared with the control, I3V administration of metformin decreased body weight and food intake in a dose-dependent manner and did not result in CTA. Furthermore, the reduction in food intake induced by I3V administration of metformin was accomplished by decreases in both nocturnal meal size and number. Compared with the control, I3V administration of metformin significantly increased phosphorylation of S6K at Thr389 and AMPK at Ser485/491 in the mediobasal hypothalamus, while AMPK phosphorylation at Thr172 was not significantly altered. Moreover, I3V rapamycin pretreatment restored the metformin-induced anorexia and weight loss. These results suggest that the reduction in food intake induced by the central administration of metformin in the mice may be mediated by activation of S6K pathway.


2011 ◽  
Vol 4 (1) ◽  
pp. 31-33
Author(s):  
Merel J. Cox ◽  
David Chiszar ◽  
Hobart M. Smith

Nine neonatal and juvenile snakes, four vipers and five nonvipers, were fed rodent meals varying in size, expressed as percent of snake body weight. The number of mandibular protractions and the time to complete swallowing were recorded, with both measures increasing linearly as a function of meal size. These young snakes routinely swallowed meals that were 50% of body weight, and ranged up to 80%, far higher than meals reported by previous workers studying adult vipers (36.4%) and nonvipers (18.4%). Furthermore, the slopes of regressions relating mandibular protractions to meal size in all of our snakes were lower than comparable slopes for adult vipers or nonvipers. We hypothesized that the relatively long and wide skulls of young snakes (i.e., as proportion of body length) were responsible for these ingestive accomplishments, with negative allometric growth being responsible for performance changes during ontogeny.


Obesity ◽  
2021 ◽  
Vol 29 (3) ◽  
pp. 601-609
Author(s):  
Giulia Pestoni ◽  
Linda Habib ◽  
Emilie Reber ◽  
Sabine Rohrmann ◽  
Kaspar Staub ◽  
...  

INDIAN DRUGS ◽  
2013 ◽  
Vol 50 (11) ◽  
pp. 34-38
Author(s):  
T. Shyam ◽  
◽  
S Ganapaty

Four compounds viz α-amyrin, β- amyrin, bauerenol and ellagic acid were isolated from the methanolic extract of Rotula aquatica roots. The structures of these compounds were elucidated on the basis of spectroscopic data analysis and chemical evidence. The extract was evaluated for hepatoprotective activity against carbon tetrachloride induced hepatotoxic model at a dose levels of 200,400 and 800 mg/ kg body weight and compared with that of the standard silymarin (25mg/kg body weight). It showed good hepatoprotective activity in a dose dependent manner. The extract was also screened for antimicrobial activity against various types of organisms like bacteria and fungi.


Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Marcin Dobaczewski ◽  
Marcin Bujak ◽  
Carlos Gonzalez ◽  
Na Li ◽  
Xiao-Fan Wang ◽  
...  

We have recently demonstrated that the Transforming Growth Factor (TGF)-β/Smad3 pathway is activated in healing infarcts and plays an essential role in the pathogenesis of cardiac remodeling. Smad3 −/− mice were protected from the development of ventricular dilation following infarction and exhibited markedly reduced fibrosis of the peri-infarct area and the remodeling non-infarcted heart. Accordingly, we hypothesized that Smad3 signaling plays an essential role in regulating cardiac fibroblast function and gene expression in myocardial infarction. Surprisingly, Smad3 −/− infarcts exhibited increased peak infiltration with myofibroblasts, associated with evidence of enhanced proliferative activity. Smad3 −/− mice had a higher density of Ki-67-positive proliferating myofibroblasts in the infarcted myocardium in comparison with wildtype (WT) animals (Smad3−/− 917±291 cells/mm 2 vs. WT 614±115 cells/mm 2 , p<0.05). In vitro experiments suggested that TGF-β inhibits murine cardiac fibroblast proliferation in a concentration-dependent manner and that the antiproliferative effects of TGF-β are abrogated in Smad3 −/− fibroblasts. On the other hand Smad3 signaling was essential for extracellular matrix protein synthesis by cardiac fibroblasts. TGF-β-mediated induction of procollagen type III and of the matricellular protein tenascin-C in cardiac fibroblasts was dependent on Smad3. In addition, TGF-β-induced Tissue Inhibitor of Metalloproteinases (TIMP)-1 and -2 upregulation was also abrogated in Smad3 −/− fibroblasts, suggesting that Smad3 signaling regulates matrix metabolism. In vivo, Smad3 −/− infarcts exhibited attenuated tenascin-C and collagen deposition in the infarct and in the remodeling non-infarcted heart. Our findings suggest that the Smad3 pathway critically regulates fibroblast function in healing myocardial infarction. In Smad3 −/− mice, the healing infarct contains abundant myofibroblasts that exhibit enhanced proliferative activity, but have markedly decreased ability to synthesize extracellular matrix proteins and to produce TIMPs. In the absence of Smad3, attenuated matrix deposition in the remodeling non-infarcted heart results in decreased dilation and ameliorated diastolic dysfunction. This research has received full or partial funding support from the American Heart Association, AHA South Central Affiliate (Arkansas, New Mexico, Oklahoma & Texas).


Author(s):  
Athesh K ◽  
Joshi G

Objective: To study the anti-obesity potential of aqueous rhizome extract of Acoruscalamus Linn. (AREAC)in high fat diet fed obese rats.Methods: Adult strain male Wistar rats used in this study were fed with High Fat Diet (HFD) for 60 days. For the treatment groups,AREAC was administered in a dose levels of100, 200 and 300 mg/kgbw, orally once a day along with HFD. Rats fed with normal pellet chow were served as normal control. The effect of AREAC on physical parameterssuch as body weight, organ weight, fat pad weights and various biochemical parameterslike serum glucose, insulin, leptin,lipid profile, liver markers, kidney markers and oxidative stress markers were analysed.In-vitro pancreatic lipase inhibition assay of AREAC was also studied.Results: Data of in-vivo studies revealedsignificant (p<0.05) reduction in percentage body weight gain, organ weights, fat pad weights and levels of serum glucose, insulin and leptin after treatment with AREAC in a dose dependent manner. Also, administration of AREAC significantly inhibited the increases in the concentrations of triglycerides, total cholesterol, LDL-cholesterol, VLDL-cholesterol, free-fatty acid and phospholipids in a dose dependent manner whereas, the level of HDL-cholesterol was found to be elevated on treatment. Moreover, on treatment with test drug,the elevated levels of serum liver and kidney markerssuch as AST, ALT, ALP, urea, creatinine were also brought back to near normalcy. Antioxidant status was found to be enhanced in liver tissues after treatment.In-vitro studies showed significant inhibition in the activity of pancreatic lipaseby AREAC.Conclusion: The data of the results obtained clearly depicted that AREAC was found to have pronounced anti-obesity activity particularly at the dose levels of 300 mg/kg bw.Key Words: Obesity, High Fat Diet, Leptin, AcoruscalamusLinn., Orlistat.  


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