Lecture 33: Neurocircuitry of Metabolism 5 Flashcards
If the levels of leptin and insulin are elevated in the blood how is this going to effect AgRP and POMC and their physiological output?
increased leptin and insulin will inhibit AgRP and activate POMC neurons
this will promote energy expenditure, repress HGP and reduce food intake
What is lost in obesity?
the plasticity of the brain window
How are AgRP neurons affected when fasted? How are these neurons affected during refeeding?
AgRP neurons are activated when fasted as they induce feeding behaviour
AgRP neuronal firing is then diminished upon refeeding
When is the feeding induced suppression of AgRP neurons lost?
in obesity
What do you predict will happen if AgRP neurons are always turned on?
increased food intake, increased adiposity, increased blood glucose levels
What happens when neurons in the ARC become resistant to the effects of leptin in the blood?
this attenuates alpha-MSH release and downstream activation of other hypothalamic nuclei (including the PVH)
What is the role of protein tyrosine phosphatases?
dephosphorylate tyrosine residues on proteins and, therefore, control cellular signalling along with protein tyrosine kinases
What is the role of PTP1B?
negatively regulates LepR signalling
What is the role of TCPTP?
negatively regulates IR signalling
What is the significance of PTP1B and TCPTP in obesity?
expression of PTP1B and TCPTP is significantly increased in the ARC in obesity
If the levels of TCPTP and PTP1B are elevated in ARC neurons what’s going to happen to physiological outputs such as WAT browning and HGP?
WAT browning will decrease and HGP will increase
What occurs during cellular leptin resistance?
neurons in the ARC become resistant to the effects of leptin in the blood
