Satiety induced by bile acids is mediated via vagal afferent pathways
JCI INSIGHT
Authors: Wu, Xiaoyin; Li, Ji-Yao; Lee, Allen; Lu, Yuan-Xu; Zhou, Shi-Yi; Owyang, Chung
Abstract
The aim of this study was to elucidate the role and the pathways used by bile acid receptor TGR5 in transmitting satiety signals. We showed TGR5 colocalized with cholecystokinin type A (CCK-A) receptors in a subpopulation of rat nodose ganglia (NG) neurons. Intra-arterial injection of deoxycholic acid (DCA) dose-dependently increased firing rate in NG while a subthreshold dose of DCA and CCK-8 increased firing rates synergistically. TGR5-specific agonist oleanolic acid induced NG neuronal firing in a dose-dependent manner. However, the same units did not respond to GW4064, a nuclear receptor-specific agonist. Quantity of DCA-activated neurons in the hypothalamus was determined by c-Fos expression. Combining DCA and CCK-8 caused a 4-fold increase in c-Fos activation. In the arcuate nucleus, c-Fos-positive neurons coexpressed cocaine and amphetamine regulated transcript and proopiomelanocortin. DCA-induced c-Fos expression was eliminated following truncal vagotomy or silencing of TGR5 in the NG. Feeding studies showed intravenous injection of 1 mu g/kg of DCA reduced food intake by 12% +/- 3%, 24% +/- 5%, and 32% +/- 6% in the first 3 hours, respectively. Silencing of TGR5 or CCK-A receptor in the NG enhanced spontaneous feeding by 18% +/- 2% and 13.5% +/- 2.4%, respectively. When both TGR5 and CCK-A receptor were silenced, spontaneous feeding was enhanced by 37% +/- 4% in the first 3 hours, suggesting that bile acid may have a physiological role in regulating satiety. Working in concert with CCK, bile acid synergistically enhanced satiety signals to reduce spontaneous feeding.
A Biotic Support During Pregnancy to Strengthen the Gastrointestinal Performance in Puppies
FRONTIERS IN VETERINARY SCIENCE
Authors: Melandri, Monica; Aiudi, Giulio Guido; Caira, Michele; Alonge, Salvatore
Abstract
Up to 60% of neonates can be affected by gastroenteritis due to specific pathogens or aspecific polymicrobial interactions. The present study evaluated if a dietary supplementation with MOS, FOS,E. faeciumandL. acidophilusin pregnancy may reduce gastroenteritis in puppies. Fifteen Great Danes were divided in 3 groups. The control group (CG) ate a standard diet. In 2 study groups, the diet was supplemented with pre- and probiotics during the last (1WG) and the last 4 pregnancy weeks (4WG). Up to 9 weeks, puppies were checked daily to identify first- or second- presentation gastroenteritis. Data were processed by chi(2)(P< 0.05). First-presentation gastroenteritis was more frequent in CG than in 1WG than in 4WG. Second-presentation gastroenteritis was more frequent in CG than in 1 and 4WG. Puppies from pre- and probiotics supplemented bitches were less prone to gastroenteritis. 1 or 4WG equally reduced second-presentation gastroenteritis in puppies, but 4WG was better than 1WG on first-presentation gastroenteritis. By entero-mammary link, supplemented bitches produced higher immune quality colostrum, thus puppies faced immunitary challenges better; moreover, maternal microbiota, positively altered by supplementation, was transferred to newborns, becoming more resistant to gastroenteritis. This information can be useful in clinical practice with the goal of preventing gastroenteritis in puppies and reducing its prevalence and severity.