Intraintestinal Delivery of Tastants Using a Naso-Duodenal-Ileal Catheter Does Not Influence Food Intake or Satiety

Intraduodenal activity of taste receptors reduces food intake. Taste receptors are expressed throughout the entire gastrointestinal tract. Currently, there are no data available on the effects of distal taste receptor activation. In this study, we investigate the effect of intraduodenal and/or intraileal activation of taste receptors on food intake and satiety. In a single-blind randomized crossover trial, fourteen participants were intubated with a naso-duodenal-ileal catheter and received four infusion regimens: duodenal placebo and ileal placebo (DPIP), duodenal tastants and ileal placebo (DTIP), duodenal placebo and ileal tastants (DPIT), duodenal tastants and ileal tastants (DTIT). Fifteen minutes after cessation of infusion, subjects received an ad libitum meal to measure food intake. Visual analog scale scores for satiety feelings were collected at regular intervals. No differences in food intake were observed between the various interventions (DPIP: 786.6 ± 79.2 Kcal, DTIP: 803.3 ± 69.0 Kcal, DPIT: 814.7 ± 77.3 Kcal, DTIT: 834.8 ± 59.2 Kcal, p = 0.59). No differences in satiety feelings were observed. Intestinal infusion of tastants using a naso-duodenal-ileal catheter did not influence food intake or satiety feelings. Possibly, the burden of the four-day naso-duodenal-ileal intubation masked a small effect that tastants might have on food intake and satiety.

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Effects of Indoor Thermal Environment on Human Food Intake, Productivity, and Comfort: Pilot, Randomized, Crossover Trial

Obesity ◽

10.1002/oby.22328 ◽

2018 ◽

Vol 26 (12) ◽

pp. 1826-1833 ◽

Cited By ~ 2

Author(s):

Molly B. Richardson ◽

Peng Li ◽

Julia M. Gohlke ◽

David B. Allison

Keyword(s):

Food Intake ◽

Crossover Trial ◽

Thermal Environment ◽

Human Food ◽

Indoor Thermal Environment ◽

Randomized Crossover Trial

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Expression of Taste Receptor 2 Subtypes in Human Testis and Sperm

Journal of Clinical Medicine ◽

10.3390/jcm9010264 ◽

2020 ◽

Vol 9 (1) ◽

pp. 264 ◽

Cited By ~ 2

Author(s):

Laura Governini ◽

Bianca Semplici ◽

Valentina Pavone ◽

Laura Crifasi ◽

Camilla Marrocco ◽

...

Keyword(s):

Taste Receptor ◽

Receptor Activation ◽

Taste Buds ◽

The Body ◽

Semen Parameters ◽

Human Testis ◽

Taste Receptors ◽

Organ Systems

Taste receptors (TASRs) are expressed not only in the oral cavity but also throughout the body, thus suggesting that they may play different roles in organ systems beyond the tongue. Recent studies showed the expression of several TASRs in mammalian testis and sperm, indicating an involvement of these receptors in male gametogenesis and fertility. This notion is supported by an impaired reproductive phenotype of mouse carrying targeted deletion of taste receptor genes, as well as by a significant correlation between human semen parameters and specific polymorphisms of taste receptor genes. To better understand the biological and thus clinical significance of these receptors for human reproduction, we analyzed the expression of several members of the TAS2Rs family of bitter receptors in human testis and in ejaculated sperm before and after in vitro selection and capacitation. Our results provide evidence for the expression of TAS2R genes, with TAS2R14 being the most expressed bitter receptor subtype in both testis tissue and sperm cells, respectively. In addition, it was observed that in vitro capacitation significantly affects both the expression and the subcellular localization of these receptors in isolated spermatozoa. Interestingly, α-gustducin and α-transducin, two Gα subunits expressed in taste buds on the tongue, are also expressed in human spermatozoa; moreover, a subcellular redistribution of both G protein α-subunits to different sub-compartments of sperm was registered upon in vitro capacitation. Finally, we shed light on the possible downstream transduction pathway initiated upon taste receptor activation in the male reproductive system. Performing ultrasensitive droplets digital PCR assays to quantify RNA copy numbers of a distinct gene, we found a significant correlation between the expression of TAS2Rs and TRPM5 (r = 0.87), the cation channel involved in bitter but also sweet and umami taste transduction in taste buds on the tongue. Even if further studies are needed to clarify the precise functional role of taste receptors for successful reproduction, the presented findings significantly extend our knowledge of the biological role of TAS2Rs for human male fertility.

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Effect of oral or intragastric delivery of the bitter tastant quinine on food intake and appetite sensations: a randomised crossover trial

British Journal Of Nutrition ◽

10.1017/s0007114520002536 ◽

2020 ◽

Vol 125 (1) ◽

pp. 92-100

Author(s):

Tim Klaassen ◽

Daniel Keszthelyi ◽

Annick M. E. Alleleyn ◽

Ellen Wilms ◽

Aalt Bast ◽

...

Keyword(s):

Food Intake ◽

Crossover Trial ◽

Eating Behaviour ◽

Intragastric Administration ◽

Taste Receptors ◽

Sham Feeding ◽

Intraduodenal Infusion ◽

Desire To Eat ◽

Analogue Scales ◽

Stimulation Of

AbstractStimulation of gastrointestinal taste receptors affects eating behaviour. Intraduodenal infusion of tastants leads to increased satiation and reduced food intake, whereas intraileal infusion of tastants does not affect eating behaviour. Currently, it is unknown whether oral- or intragastric administration of tastants induces a larger effect on eating behaviour. This study investigated the effects of oral- and/or intragastric administration of quinine on food intake, appetite sensations and heart rate variability (HRV). In a blinded randomised crossover trial, thirty-two healthy volunteers participated in four interventions with a 1-week washout: oral placebo and intragastric placebo (OPGP), oral quinine and intragastric placebo (OQGP), oral placebo and intragastric quinine (OPGQ) and oral quinine and intragastric quinine (OQGQ). On test days, 150 min after a standardised breakfast, subjects ingested a capsule containing quinine or placebo and were sham-fed a mixture of quinine or placebo orally. At 50 min after intervention, subjects received an ad libitum meal to measure food intake. Visual analogue scales for appetite sensations were collected, and HRV measurements were performed at regular intervals. Oral and/or intragastric delivery of the bitter tastant quinine did not affect food intake (OPGP: 3273·6 (sem 131·8) kJ, OQGP: 3072·7 (sem 132·2) kJ, OPGQ: 3289·0 (sem 132·6) kJ and OQGQ: 3204·1 (sem 133·1) kJ, P = 0·069). Desire to eat and hunger decreased after OQGP and OPGQ compared with OPGP (P < 0·001 and P < 0·05, respectively), whereas satiation, fullness and HRV did not differ between interventions. In conclusion, sole oral sham feeding with and sole intragastric delivery of quinine decreased desire to eat and hunger, without affecting food intake, satiation, fullness or HRV.

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G Protein-Coupled Receptors in Taste Physiology and Pharmacology

Frontiers in Pharmacology ◽

10.3389/fphar.2020.587664 ◽

2020 ◽

Vol 11 ◽

Author(s):

Raise Ahmad ◽

Julie E. Dalziel

Keyword(s):

Binding Site ◽

G Protein ◽

Molecular Mechanisms ◽

Taste Receptor ◽

Receptor Activation ◽

G Protein Coupled Receptors ◽

Type I ◽

Taste Receptors ◽

Agonist Binding ◽

G Protein Coupled

Heterotrimeric G protein-coupled receptors (GPCRs) comprise the largest receptor family in mammals and are responsible for the regulation of most physiological functions. Besides mediating the sensory modalities of olfaction and vision, GPCRs also transduce signals for three basic taste qualities of sweet, umami (savory taste), and bitter, as well as the flavor sensation kokumi. Taste GPCRs reside in specialised taste receptor cells (TRCs) within taste buds. Type I taste GPCRs (TAS1R) form heterodimeric complexes that function as sweet (TAS1R2/TAS1R3) or umami (TAS1R1/TAS1R3) taste receptors, whereas Type II are monomeric bitter taste receptors or kokumi/calcium-sensing receptors. Sweet, umami and kokumi receptors share structural similarities in containing multiple agonist binding sites with pronounced selectivity while most bitter receptors contain a single binding site that is broadly tuned to a diverse array of bitter ligands in a non-selective manner. Tastant binding to the receptor activates downstream secondary messenger pathways leading to depolarization and increased intracellular calcium in TRCs, that in turn innervate the gustatory cortex in the brain. Despite recent advances in our understanding of the relationship between agonist binding and the conformational changes required for receptor activation, several major challenges and questions remain in taste GPCR biology that are discussed in the present review. In recent years, intensive integrative approaches combining heterologous expression, mutagenesis and homology modeling have together provided insight regarding agonist binding site locations and molecular mechanisms of orthosteric and allosteric modulation. In addition, studies based on transgenic mice, utilizing either global or conditional knock out strategies have provided insights to taste receptor signal transduction mechanisms and their roles in physiology. However, the need for more functional studies in a physiological context is apparent and would be enhanced by a crystallized structure of taste receptors for a more complete picture of their pharmacological mechanisms.

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The effects of kefir in mixed meals on appetite and food intake: a randomized cross-over trial

Revista de Nutrição ◽

10.1590/1678-9865202134e190174 ◽

2021 ◽

Vol 34 ◽

Author(s):

Zeynep CAFEROGLU ◽

Gizem AYTEKIN SAHIN

Keyword(s):

Food Intake ◽

Energy Intake ◽

Glycemic Index ◽

Crossover Trial ◽

Fermented Milk ◽

Randomized Crossover Trial ◽

High Glycemic Index ◽

Dietary Strategies ◽

Healthy Females ◽

Low Glycemic Index

ABSTRACT Objective The natural probiotic kefir is fermented milk, and may have effects on satiety and voluntary energy intake. This randomized crossover trial aimed to determine whether kefir, consumed with low- or high-glycemic index meals, affects appetite and subsequent food intake. Methods Twenty four healthy females aged 21-24 years, were recruited from Erciyes University and the surrounding community. The participants were submitted to three different breakfasts: a low glycemic index accompanied by milk, a low glycemic index with kefir, and a high glycemic index with kefir, with a 1-week washout period between meals. At 0, 15, 30, 60, 90, 120, 150, and 180 minutes after the meal, appetite ratings were measured by the visual analog scale, and then ad libitum lunch was served. Results No differences in appetite scores and voluntary energy intake were detected between the test meals. Furthermore, palatability ratings were similar between test meals, except for the higher score of high glycemic index kefir for overall palatability. Conclusion This study demonstrated that adding kefir to a high glycemic index meal may prevent increases in appetite and food intake, resulting in postprandial responses similar to those of a low glycemic index meal. These findings might enable the development of novel dietary strategies based on appetite regulation to treat or prevent obesity, particularly for Western societies. This trial was registered at ClinicalTrials.gov under the process NCT03636217.

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Effectiveness of weak wiping pressure during bed baths in hospitalized older adults: A single-blind randomized crossover trial

Geriatric Nursing ◽

10.1016/j.gerinurse.2021.09.008 ◽

2021 ◽

Vol 42 (6) ◽

pp. 1379-1387

Author(s):

Issei Konya ◽

Hiroaki Iwata ◽

Miyuki Hayashi ◽

Tamami Akita ◽

Yoshie Homma ◽

...

Keyword(s):

Older Adults ◽

Crossover Trial ◽

Randomized Crossover Trial ◽

Hospitalized Older Adults ◽

Single Blind

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Cholesterol ester transfer protein polymorphism rs5882 is associated with triglyceride-lowering in response to plant sterol consumption

Applied Physiology Nutrition and Metabolism ◽

10.1139/apnm-2015-0039 ◽

2015 ◽

Vol 40 (8) ◽

pp. 846-849 ◽

Cited By ~ 5

Author(s):

Dylan S. Mackay ◽

Peter K. Eck ◽

Todd C. Rideout ◽

David J. Baer ◽

Peter J.H. Jones

Keyword(s):

Clinical Trial ◽

Cholesteryl Ester Transfer Protein ◽

Plant Sterol ◽

Crossover Trial ◽

Human Clinical Trial ◽

Transfer Protein ◽

Randomized Crossover Trial ◽

Clinical Trial Evidence ◽

Trial Evidence ◽

Single Blind

Recent work suggests that plant sterol (PS) consumption may lower triglyceride (TG) concentrations; however, human clinical trial evidence is inconsistent. We associated SNP r5882 in cholesteryl ester transfer protein with changes in TG concentrations following PS consumption (2 g/day for 4 weeks) in a dual-centre, single-blind, randomized, crossover trial. TG concentrations were lowered in homozygotes for the minor G-allele of rs5882 (–0.46 ± 0.13 mmol/L, p = 0.002, n = 10); there was no effect in the A-allele carriers.

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Activation of ovarian taste receptors inhibits progesterone production potentially via NO/cGMP and apoptotic signaling

Endocrinology ◽

10.1210/endocr/bqaa240 ◽

2020 ◽

Author(s):

Jingle Jiang ◽

Siyi Liu ◽

Lina Qi ◽

Quanwei Wei ◽

Fangxiong Shi

Keyword(s):

Nitric Oxide ◽

Taste Receptor ◽

Receptor Activation ◽

Mapk Signaling ◽

Mitogen Activated Protein Kinase ◽

No Production ◽

Taste Receptors ◽

Apoptotic Signaling ◽

Progesterone Production ◽

Saccharin Sodium

Abstract Taste receptors are not only expressed in the taste buds, but also in other non-gustatory tissues, including the reproductive system. Taste receptors can be activated by various tastants, thereby exerting relatively physiologic functions. The aim of this study was to investigate the effects and potential mechanisms underlying ovarian taste receptor activation on progesterone production using saccharin sodium as the receptor agonist in a pseudopregnant rat model. Taste 1 receptor member 2 (TAS1R2) and taste 2 receptor member 31 (TAS2R31) were demonstrated to be abundantly expressed in the corpora lutea of rats, and intraperitoneal injection of saccharin sodium can activate both of them and initiate their downstream signaling cascades. The activation of these ovarian taste receptors promoted nitric oxide (NO) production via endothelial nitric-oxide synthase (eNOS). The NO production then increased ovarian cyclin guanosine 3’,5’-monophosphase (cGMP) levels, which, in turn, decreased ovarian cyclin adenosine 3’,5’-monophosphase (cAMP) levels. In addition, the activation of ovarian taste receptors induced apoptosis, possibly through NO and mitogen-activated protein kinase (MAPK) signaling. As a result, the activation of ovarian taste receptors reduced the protein expression of steroidogenesis-related factors, causing the inhibition of ovarian progesterone production. In summary, our data suggest that the activation of ovarian taste receptors inhibits progesterone production in pseudopregnant rats, potentially via NO/cGMP and apoptotic signaling.

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