Food and Metabolism Flashcards
Do metabolism have an effect on behavior?
Surprisingly, it does. In worms, MC (E) and M3 (I) neurons regulate worm response to food. They even exhibit satiety because speed on food is lower when it has already been fed. They do that by knowing if they have glucose by the presence of insulin in their metabolism.
What is the Dauer metabolism?
It is the state a worm gets into when conditions are bad (pheromones, heat or no food). Metabolism (++ fat stored), morphology (mouth closed) and behavior change (not moving) consequently.
What determines if c. elegans will enter into dauer or not?
It is due to the sensory inputs because when you remove some sensory neurons, you can get dauer even in non-dauer conditions, especially if you remove ASI and ADF neurons.
What is the role of insulin in dauer?
It regulates entry to dauer.
No insulin = dauer
No insulin receptor in intestines (DAF-2) = dauer
Usually inhibits DAF-16 which is a TF activating entry into dauer.
What is the effect in fat when you KO DAF-2? DAF-2 and DAF -16? Tub 1?
DAF-2 KO = ++ fat stored
DAF-2/16 KO = same as WT
Tub-1 = ++ fat stored
How do Drosophila regulates food metabolism?
By using insulin-like peptides (Dlip) that are produced by neurons in the brain with processings extending to oesophagus and heart. These neurons release it only when you have glucose in the body.
What is regulating insulin releasing neurons in Drosophila?
- Electrical activity from the brain: hyperpolarized = no insulin released
- Fat : Lot of fat = ++ release, fat release a chemical (leptin) interacting with the brain
In mice, what are the genes that are doing something in fat storage?
Obese (ob) = leptin (found in fat)
Diabetic (db) = leptin receptor
Tubby (tb) = somewhere in the pathway of leptin reception and behavior, expressed in the arcuate nucleus
What are the 2 neurons types you have in the arcurate nucleus?
Pomc and Agrp/NPY
What happens when you activateAgRP? POMC?
AgRP = eat a lot, when inhibited, you don’t eat at all, they are necessary (sensitive to diphteria toxin (can’t release NT anymore), rescued by Bretazenil)
POMC = eat less
They both respond to leptin and insulin.
Are AgRP and POMC neurons part of the same neuronal circuit?
No, because POMC needs melanocortin receptor while AGRP does not to control food intake. Melanocortin-4-receptors (t) act in the paraventricular hypothalamus to regulate food intake but not energy consumption, therefore, POMC and AgRP does not regulate food intake the same way.
