Browsing by Subject "Feeding Behavior"
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Item A Cross-Cultural Examination of Parenting Style and Feeding Practices(2011-02-01) Hinton, Leilani Kaulana; Holub, ShaylaChildhood obesity is an issue of great concern to health professionals in the United States. Past research has emphasized the role parenting styles (e.g., the global parenting environment) and parents? practices (e.g., specific parent behaviors) play in shaping childhood weight status. This study is the first to examine the associations of parenting style, feeding practices and children?s self-regulation of food intake in a South Asian population. Self-report data was collected from a community sample of South Asian parents with children between the ages of 3 to 9 years old (N = 54). Participants were 75% mothers and 25% fathers. Feeding practices were compared between South Asian mothers and data from a control group that was collected from an ongoing study. Survey items measured parenting style dimensions of warmth, psychological control, and behavioral control. Parents? controlling feeding practices of pressure, restriction for health and restriction for weight were also assessed. Self-regulation was measured by parent?s report of child?s external eating and food responsiveness, as well as satiety responsiveness. Results of this study revealed South Asian mothers used more pressure in feeding than Caucasian mothers, but did not use more restriction. Acculturation was not associated with parenting style dimensions or feeding practices, but was associated with external eating. The parenting style dimension of psychological control was positively correlated with restriction for health and pressure. Psychological control and restriction for health were associated with external eating, while these variables and restriction for weight were associated with food responsiveness. Regression analyses suggest that restriction for health was the best predictor for both of these variables. Restriction for weight was related to satiety responsiveness, but this variable was not significant after controlling for child weight status. The results of this study are consistent with previous research on feeding practices and self-regulation. Parenting interventions targeting child obesity should consider teaching parents to employ less controlling feeding practices, as these methods were associated with lower self-regulation ability in children.Item Electrophysiological and Behavioral Mechanisms of Caenorhabditis Elegans Feeding(2004-12-15) Shtonda, Boris Borisovich; Avery, LeonThe nematode (roundworm) Caenorhabditis elegans lives in soil and eats bacteria. Its feeding organ is a neuromuscular pump called the pharynx. First, I developed a voltage clamp preparation for the pharynx and recorded native ionic current in the pharyngeal muscle. I showed that a T-type Ca channel CCA-1, an L-type Ca channel EGL-19 and a potassium channel EXP-2 shape pharyngeal action potentials. CCA-1 works in the pharyngeal muscle to boost its response to neurotransmission from the MC pharyngeal neuron. Next, EXP-2 is not an inward rectifier in the pharynx; it generates large currents upon hyperpolarization and has nearly linear voltage dependence. Finally, the pharynx adapts to the loss of MC excitatory inputs by raising its resting membrane potential, which makes it more excitable. Second, I studied food seeking and food preference behaviors in C.elegans. In the laboratory, C.elegans is routinely kept on plates seeded with E.coli, and it is not known how worms behave in an environment where diverse food is available. I identified additional food sources, such as Bacillus megaterium, Comamonas sp., and Bacillus simplex, and showed that bacterial food varies in quality. C.elegans hunts for the food of higher quality, the one that better supports growth. This seeking activity is further enhanced in animals that have already experienced good food. Next, the food regulates C.elegans locomotion, particularly the equilibrium between two locomotion modes, known as roaming and dwelling. On good food, dwelling is more common, on poor food, roaming is predominant. The normal balance between these states is essential for the food seeking behavior. In ttx-3 and osm-6 mutants the food-dependent equilibrium between locomotion states is impaired: worms tend to spend less time roaming on poor food. ttx-3 defects are partially reproduced by laser ablation of AIY interneurons, suggesting that AIY functions to inhibit the roaming-to-dwelling transition and to extend food-seeking periods. On the other hand, tax-6 mutants show increased roaming even on high quality food. tax-6, osm-6 and ttx-3 mutants are defective in food choice behavior. C.elegans may serve as a new system to uncover mechanisms that enable animals to find high quality food in diverse environments.Item Familiar Food-Induced Feeding Activation in C. Elegans(2011-08-10) Song, Bo-mi; Avery, LeonThe growing epidemic of obesity and eating disorders demands the study of regulatory mechanisms of food intake. Studying mutants whose food intake is altered under various conditions has greatly advanced our understanding of the mechanism. However, it is still largely unknown by which mechanisms perception of food activates food intake. The simple anatomy, genetic tractability, and well-characterized and quantifiable feeding behavior and evolutionary conservation of feeding regulators make C. elegans an attractive model system for the study. Food intake in C. elegans requires two muscle motions, pharyngeal pumping and isthmus peristalsis, and the frequencies of the two feeding motions dramatically increase in response to food as in other organisms. I attempted to understand the mechanism underlying food-induced feeding activation by studying the mechanism and the physiological context of action of serotonin, an endogenous activator of pharyngeal pumping. Here I show that like food, serotonin increases overall feeding by activating both feeding motions. Serotonin activates the two feeding motions by activating two distinct neural pathways. A 5-HT7 receptor activated the two motions mainly by acting in the two distinct pharyngeal motor neurons that are essential for food-induced feeding activation. Moreover, the results support that the serotonin receptor activated the two distinct neurons mainly by activating two distinct downstream G protein signaling pathways. Despite the separate regulation, isthmus peristalsis was coupled to the preceding pharyngeal pump. The separate regulation with coupling of the two feeding motions may have evolved to support efficient feeding by allowing control of the ratio of the frequencies of the two muscle motions according to density of food and by preventing futile isthmus peristalsis. Then, which aspect of food triggers the serotonin signal that increases food intake? I found that recognition of familiar food selectively triggers the serotonin signal. Worms selectively consume particular bacteria more actively after experience and the behavioral plasticity requires serotonin signaling. By dissecting the mechanism, I found that recognition of familiar food triggers serotonin release from a pair of chemosensory neurons. The released serotonin acts as an endocrine signal to increase pharyngeal pumping rate by activating the pharyngeal motor neuron that directly triggers pharyngeal pumping. The results suggest that worms form a memory of previously experienced food and that the memory controls food intake. Consistently, the familiar-food induced feeding was strongly dependent on duration of exposure to food to learn but not developmental timing of exposure or nutritional status. Furthermore, worms could remember the previously experienced food at least for several hours. My study provides insight into how feeding organ operates to increase food intake in response to food and how a particular aspect of food controls the process to increase food intake in C. elegans. Studying familiar food-induced feeding activation may help us understand the mechanisms underlying perception of different food and encoding, retention and retrieval of the memory of familiar food.Item Impact of a Community-Developed Nutrition Fotonovela Versus a Brochure on Dietary Practice in the Dominican Republic(2020-03-16) Jean, Alice; Gimpel, Nora; Albin, Jaclyn; Carson, Jo AnnBACKGROUND: Cardiovascular disease is the number one cause of mortality in the Dominican Republic, and diet is one of the main factors contributing to its development (World Health Organization, 2016; Mokdad et al., 2018). A fotonovela is similar to a comic book but uses photographs to tell a story about a health topic and has been shown to increase awareness and promote healthier practices. OBJECTIVE: After two weeks and one month, participants experiencing the community-developed nutrition fotonovela will display more changes in dietary behavior than the participants experiencing the nutrition brochure. METHODS: Zumbón was randomly selected from five communities surrounding Santo Domingo to develop a fotonovela about eating a balanced diet through focus groups. Haina and El Batey were the intervention groups in which the pastors presented the fotonovela to the communities while San Joaquín and Tres Brazos were control groups in which the pastors presented an existing nutrition brochure to the communities. Before the presentation, the participants completed a survey containing demographic and dietary behavior questions. To evaluate whether the fotonovela or brochure intervention significantly changed their diet, participants completed an identical survey two weeks and one month after the presentation. RESULTS: Besides differences in gender, cooking ability, employment, and household composition, there were no other demographic differences within the brochure and fotonovela presentation communities. With a p-value of less than 0.05 being significant, people in Haina were eating starches more often two weeks after the fotonovela presentation. In San Joaquín, significantly more people ate grains daily at one month than before the brochure presentation. In the brochure presentation communities of San Joaquín and Tres Brazos, significantly more people ate no added fat at the one month survey compared to the two week survey. No other significant dietary changes were found within the brochure and fotonovela presentation communities when comparing pre- to post-presentation surveys. CONCLUSION: Although differences in dietary changes between those receiving the brochure versus fotonovela were limited, the brochure presentation communities made more preferable changes in their diet than the fotonovela presentation communities within a one-month period. Nutrition brochures are effective in promoting a healthy diet while fotonovelas can potentially have long-term beneficial effects on diet. Future studies are recommended to distribute color copies of the fotonovela to a larger sample size and to follow participants' eating habits beyond one month.Item Investigating the Enteroendocrine - Brain Axis: Ghrelin Cell and ECL Cell Physiology and Ghrelin Action on Mood and Complex Eating(2014-06-11) Walker, Angela Kay; Eisch, Amelia J.; Powell, Craig M.; Scherer, Philipp; Zigman, Jeffrey M.The mechanisms and neurochemical pathways through which the orexigenic peptide hormone ghrelin act to regulate homeostatic feeding is fairly well documented. However, less understood are the mechanisms and brain regions that mediate ghrelin's effects on mood and complex eating behaviors. At the cellular level, little is known about the ghrelin cell's transcriptional profile, its secretory products other than ghrelin, and its relationship to other gastric endocrine cells, such as the histamine producing enterochromaffin-like cell. My doctoral research encompasses multiple aspects of the ghrelin system, from physiological assessments of the ghrelin cell to evaluations of ghrelin action on cue-potentiated feeding and stress-induced depressive-like behavior. Ghrelin has antidepressant effects, which become obvious following chronic stress. In the first part of my thesis, I found that this effect was mediated by neurogenesis. I observed that chronic stress reduces neurogenesis more severely in the ventral dentate gyrus of Ghsr-null mice, suggesting ghrelin provides a level of neuroprotection in the stress environment. Administration of anti-apoptotic P7C3-related compounds not only blocked stress-induced reductions in neurogenesis, but also minimized the severity of depressive-like behavior in mice. Focal hippocampal irradiation prevented the anti-depressant efficacy of P7C3-related compounds, indicating that P7C3 regulates mood directly through neurogenesis. In the second part of my thesis, I designed a novel protocol for studying cue-potentiated feeding behaviors in mice. Absence of ghrelin signaling in Ghsr-null mice, or administration of a ghrelin receptor antagonist in wild-type mice, disrupted the development of normal cue-food associations. Additionally, I discovered Ghsr expression in the basolateral amygdala (BLA), and BLA neuronal activation in response to a food-associated positive cue significantly correlated with amount of food intake. Thus, ghrelin signaling in the BLA may be responsible for its mediation of cue-potentiated feeding behaviors. The third part of my thesis examined the ghrelin cell transcriptome for potential secretory proteins and revealed significant expression of Rbp4, Ttr, and Nucb2, along with RBP4 protein secretion. Lastly, I characterized a novel HDC-Cre mouse model that may be advantageous in future studies to determine potential interactions between histaminergic and ghrelin signaling pathways. The full range of these discoveries advances our comprehensive understanding of ghrelin.Item Leptin Action on Dopamine Neurons: Biochemical and Behavioral Analysis(2009-01-14) Trinko, Joseph Richard, III; DiLeone, Ralph J.It has been demonstrated that there are brain regions commonly activated by hedonic foods and drugs of abuse, and therefore, potentially common mechanisms underlying behaviors associated with them. Additionally, the metabolic state of an animal can affect drug seeking behavior. The discovery that leptin receptor (Lepr) is expressed on dopamine neurons in the ventral tegmental area (VTA) provides a link between metabolic state and rewarding behavior. By using a multitude of techniques, the functional roles for Lepr signaling on dopamine neurons have been assessed. By activating Lepr in the VTA via direct infusion of leptin, or conversely reducing Lepr signaling in the VTA with viral-mediated shRNAi, a role for VTA leptin signaling in feeding behavior was demonstrated. Lepr activation in the VTA leads to intracellular signaling pathways similar to that observed in the hypothalamus. These studies also identify differences in signaling between these two brain regions, specifically the phosphorylation of AMP-activated protein kinase (AMPK), which is opposite to what is observed in the hypothalamus. Interestingly, food restriction was found to differentially affect the signaling pathways in the VTA. Preliminary evidence also suggests a role for Lepr in saccharin and cocaine seeking behaviors. Rats with attenuated Lepr signaling in the VTA demonstrate persistent saccharin and cocaine seeking. Conversely, leptin infusions reduced lever pressing during drug withdrawal. These results are indicative of a potential role for leptin in drug and food seeking behavior. In sum, these results suggest a neuronal mechanism by which this key metabolic signal can modify both food and drug intake.Item [UT Southwestern Medical Center News](2007-02-16) Siegfried, Amanda