Psychology 2054A/B Chapter Notes - Chapter 3: Brainstem, Neuropeptide, Weight Loss
30 Sep 2016
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Around 22 million children under 5 worldwide are obese. Adult obesity increases risk of type 2 diabetes, stroke, cancer, etc. Most obese children also become obese adults. Obesity is driven by changes in diet. Commonest syndromal cause is prader-willi syndrome: lack of paternal segment of chromosome 15. When a meal is ingested, satiety hormones contribute to digestion and feeling full. Nuclei of hypothalamus and brain stem regulate energy homeostasis. Arcuate nucleus (arc) accesses signals from the periphery. 4 main neurotransmitters in the arc: orexigenic (inhance eating) Defects in neuropeptide appetite circuits can deregulate energy homeostasis resulting in obesity. Most important is msh because it inhibits food intake. Melanin concentrating hormone (mch) is a neuropeptide involved in control of food intake. The rewarding nature of food may act as a stimulus to feeding, even in the absence of energy deficit. Reward system uses opioids, dopamine, endocannabinoids and serotonin. Ghrelin in synthesized mostly in stomach used for appetite regulation.
