Control of appetite Flashcards
Define satiation and satiety. Define hunger and appetite
satiation - feeling full and terminates meal
satiety - feeling of repletion that inhibits further meals
What part of the brain controls food intake?
hypothalamus
What part of the hypothalamus integrates appetite signals? With respect to the BBB, why can gut hormones get to it?
arcuate nucleus (ARC) it isn't protected by the BBB
What does orexigenic and anorexigenic mean?
orexigenic - stimulate food intake
anorexigenic - inhibit food intake
Release of what 2 compounds stimulates food intake? Where do they come from and where do they go?
food intake - stimulated by AgRP and NPY
from the arcuate nucleus (ARC) to the orexigenic neurons
What 2 compounds inhibit food intake? Where do they come from and where do they go?
POMC and CART
from the arcuate nucleus (ARC) to anorexigenic neurones
POMC is modified to make what? What compound is an antagonist to the receptor?
generate melanocortins to act on melanocortin receptors
AgRP is the antagonist of the melanocortin receptor
What cells secrete leptin? Insulin? Ghrelin? CCK?
leptin - adipose tissue
insulin - pancreas
ghrelin and CCK- GIT
Where does CCK act?
vagus nerve
What hormones inhibit and what hormones promote appetite?
inhibit - leptin, insulin, CCK
promote - ghrelin
List some of the hormones that inhibit appetite. 6
CCK GLP-1 oxyntomodulin PYY3-36 apolipoprotein A-IV enterostatin
If food intake drops, what happens to leptin and why?
decrease in leptin so you’d remove the inhibitory effects of leptin
What is Leptin’s effects on the brain?
inhibits NPY AgRP release
activates the PMC/CART neurons
from appetite stimulation to appetite suppression
Where does insulin act on in the brain to inhibit appetite?
actions on the arcuate nucleus (ARC)
What does Ghrelin do in the brain?
Acts on arcuate nucleus or brain stem to stimulate food intake through NPY and AgRP
Where is PYY secreted from and under what conditions? Explain the physiological mechanism of PYY’s actions on the brain.
secreted from distal GIT dependent on nutrient intake or stimulated by CCK, gastric acid, bile
cleaved at acts at NPY Y2 receptor
decreases food intake
Where is CCK secreted from and under what conditions?
released from duodenum and jejunum
response to FAs
What neurotransmitter is involved when palatable food is eaten?
dopamine
Where is dopamine involved upon food consumption
dopamine release in dorsal striatum
What drug helps in weight loss involving dopamine?
bupropion is a dopamine reuptake inhibitor - more reward with less pleasurable food
What receptor is involved in food reward
What drug is the antagonist for it?
cannabinoid receptor (CB1)
rimonabant - CB1 receptor antagonist
What does orlistat do?
What is a big side effect of orlistat?
inhibits gastric and pancreatic lipase - minimal absorption
side effect - steatorrhea
what does orlistat need to be combined with? Under what conditions should it be combined with?
low fat diet, take one immediately before each main meal
if meal contains no fat then miss dose
What does saxenda do?
GLP-1 receptor agonist
appetite suppression - increases POMC/CART
GLP-1 supresses dopamine - reward pathway
