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Flashcards in Gut Hormones and Addiction Deck (29)
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Why is there an obesity epidemic?

A mismatch between easily available high-calorie food, the lack of need for exercise, and a genetic and physiological makeup designed to avoid starvation


State some internal cues for eating behaviour

Nutritional state, hormones, gender, gut cues


Name some brain regions activated in response to food

Orbitofrontal cortex and reward network (dorsal striatum, insula, nucleus accumbens, amygdala, substantia nigra, ventral tegmental area, lateral hypithalamus)


State the function of the amygdala

Emotional response


State the functions of the nucleus accumbens

Reward expectation and drive


State the functions of the dorsal striatum

Habits and learned associations


State the functions of the insula

Taste, multimodal integration, and decision making (risk-benefit)


Describe the differences in food cue responses in obese individuals

They have heightened responsivity to food cues, but on receiving the food have less brain activity - especially in the dorsal striatum and caudate


State some potential confounders in studies of obesity and food responses

BMI vs adiposity to define obesity, hormonal mediators not measured, BMI is not a behaviour measure, heterogeneity of the obese phenotype, fasted or fed nutritional state, choice of food and control pictures, differences in food preference, source of obese patients (e.g. wanting to lose weight/ dieting or not)


Food addiction is not a recognised psychiatric disorder. If it was, what would its prevalence be in those of healthy weight and overweight respectively? (Pursey et al, 2014)

Healthy weight: 11.1%
Overweight: 24.9%


Why is food addiction a controversial concept?

Food, unlike other addictive substances, is essential for life - other drugs of abuse hijack a system specifically designed for food, water, and sex. Food withdrawal is also not agreed on as existing.


Describe the differences between bariatric surgery patients who meet the hypothesised criteria for food addiction and those who do not

Those who meet criteria are more likely to have depression, anxiety, and binge eating disorder. There is no association with post-op weight loss, rehospitalisation, or attendance at follow-up appointments


Name the survey created by Gearhardt et al in 2011 to screen for food addiction

Yale Food Addiction Scale


State some behavioural components of addiction that could also seen in obesity

Compulsivity, impulsivity and risk-taking, stress and emotional response, reward sensitivity


Describe the influence of reward system activation on gut hormones

Reward system activation causes decreased in satiety hormones (leptin, insulin, GLP-1) and an increase in ghrelin, which increases appetite


How does exogenous ghrelin affect the response to food? (Goldstone et al, 2014)

It causes fasting-typical responses in the hedonic, orbitofrontal cortex, and hippocampal responses to food


How does chronic social defeat stress affect food intake in mice?

It leads to increased ghrelin, dopamine release, and an increase in high-fat food intake


How do GLP-1 receptor agonists affect food intake?

They reduce it in both lean and obese people


Name a GLP-1 receptor agonist licensed for weight loss



What is the most effective bariatric surgery procedure?

Gastric bypass


Why might gastric bypass be more effective than gastric banding? (Scholtz & Goldstone, 2014)

It excludes the small bowel, which is believed to send signals that alter eating behaviour. Gastric bypass also increases levels of satiety gut hormones and bile acids, and lowers brain hedonic responses to food


Name a bariatric intervention developed due to the hormonal influences on food intake



What affect do drugs have on gut hormones?

They increase ghrelin and GLP-1


Which system do GLP-1 analogues act on to reduce food intake?

Mesolimbic system


How does exogenous ghrelin affect alcohol intake? (Farokhnia et al, 2017)

It increases self-administration of alcohol and modulates brain activity in alcohol-dependent individuals


Describe the effect of a ghrelin receptor inverse agonist on alcohol intake (Lee et al, 2018)

It reduces the urge to drink


What form of ghrelin can bind to the ghrelin receptor?

Acetylated ghrelin


Name the enzyme which converts ghrelin to its active form



Describe the effect of de-acetylated ghrelin on weight in humans (Allas et al, 2016)

It reduces it