Zhan Article

Question 1

What is the paper topic?

Answer 1

Acute and Long-Term Suppression of Feeding Behavior by POMC Neurons in the Brainstem and Hypothalamus, Respectively

Question 2

What happens when POMC neurons are stimulated?

Answer 2

Upon the stimulation of the POMC neurons, alpha MSH is released thereby inhibiting the feeding behavior. The activation of the POMC neurons could be stimulated by insulin or leptin. So, after consuming a meal that is heavy in carbohydrates or fat for example, insulin or leptin levels rise, stimulating the POMC neurons which then suppresses the eating behaviour

Question 3

Where are POMC neurons found?

Answer 3

Populations of POMC neurons are found mainly in the arcuate nucleus in the hypothalamus and the nucleus tractus solitarius in the brainstem

Question 4

What is the hypothesis?

Answer 4

Separately stimulating POMC neurons in the ARC and NTS suppresses feeding behaviour. Ablating POMC neurons in the ARC and NTS separately leads to increased food intake

Question 5

What were some of the methods?

Answer 5

Use of transgenic mice and cre recombinase gene, viral vector injection, DREADD, selective ablation

Question 6

What were some of the results?

Answer 6

In the ARC, it’s the long-term activation of POMC neurons that suppresses feeding behavior, and not acute activation. In the NTS, it’s the acute activation of POMC neurons responsible for immediate suppression of feeding behavior; long-term activation does not lead to inhibition of feeding behavior. Ablation of POMC neurons in the ARC but not in the NTS caused: an increased food intake, reduced energy expenditure, obesity and metabolic and endocrine disorders

Question 7

What are some differences between ARC and NTS POMC neurons?

Answer 7

ARC is located in the medio basal hypothalamus. NTS is located in the dorsomedial medulla of the brainstem and is more directly involved in expressing satiety signals