Body nutrient status: Informing brain about body energy stores (Prof Ashford) Flashcards

1
Q

What are the two main methods of feedback between CNS and organs

A

Neural and endocrine

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2
Q

Describe satiety signals that control meal size

A

Upper GI tract signals via vagus nerve and sympathetic afferents converge on the nucleus of the solitary tract (NTS and hypothalamus)

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3
Q

Where does long term energy balance information mainly derive from?

A

The pancreas and adipose tissue

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4
Q

What are the three main factors that underlie regulation of food intake

A

1) Satiety signalling
2) Adiposity negative feedback signalling
3) Food reward

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5
Q

What is satiation?

A

The sensation of fullness generated during a meal

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6
Q

What is satiety?

A

Period of time between termination of one meal and the initiation of the next

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7
Q

What is adiposity?

A

The state of being obese

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8
Q

Describe ob/ob mice

A

Missing the circulating factor (the gene that encodes leptin). Causing it to become obese, hyperphagic, hyperinsulinaemic, hyperglycaemia and insulin resistant

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9
Q

Describe db/db mice

A

Lack functional receptor (gene encoding leptin receptor). Causing it to be obese, hyperphagic, hyperinsulinaemic and overtly diabetic

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10
Q

What does lack of leptin cause in relation to obesity and diabetes

A

Causes both (shit question I know I’m sorry)

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11
Q

What else is leptin required for?

A

Normal immune function, reproductive systems and regulation of blood pressure

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12
Q

Leptin on ovulation, puberty, angiogenesis and tumours

A

Thin women stop ovulating, it regulates onset of puberty, enhances angiogenesis and is produced locally in some tumours

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13
Q

What is the main leptin receptor

A

LEP-R

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14
Q

What are the splice variants of LEP-R known as

A

LEP-R a-f

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15
Q

Why is LEP-Rb most important?

A

It is the longest and has the intracellular motifs required for signalling

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16
Q

Where is leptin transported across the BBB

A

Median eminence

17
Q

Where are LEP-Rb receptors particularly abundant?

A

Hypothalamus (ARC, LHA and VMH)

18
Q

Where is leptin produced

A

White adipose tissue. Therefore plasma leptin and adipose tissue mass are highly correlated

19
Q

What effect does fasting have on leptin levels

A

Decreases leptin

20
Q

What is lipodystrophy

A

Rare disorder where individuals have few or no fat cells and store lipids elsewhere (muscle or liver) and have a high lipid level in blood. Basically fat redistribution

21
Q

What disease patients are prone to lipodystrophy

A

HIV patients

22
Q

What is the name of a synthetic injectable analogue of leptin

A

Myalept (metraleptin)

23
Q

What is rabson mendenhall syndrome

A

Extreme insulin resistance

24
Q

What two diseases can leptin therapy improve insulin resistance

A

Rabson mendenhall syndrome and HIV-1

25
What happens if you destory ARC and centrally inject leptin and what does this show
It no longer reduces food intake. This shoes LEP-Rb is localised strongly to ARC neurones (NPY and AgRP and POMC/CART)
26
Which hypothalamic mRNA does leptin increase/decrease
Increases: CART/POMC Decreases: NPY/AgRP
27
What effect does leptin have on neurites in the ARC (and which age especially?)
Increases growth and especially in neonates
28
What other molecules similar to leptin is also an adiposity signal?
Insulin
29
How does insulin get into the rain
There is an insulin related transport system in brain microvessels
30
Just rememer insulin and leptin are so similar
GOT IT????
31
Is insulin anabolic or catabolic?
Anabolic (constructs molecules from smaller ones)
32
How is insulin delivered to the hypothalamus in humans
Intranasally
33
What does insulin when delivered to hypothalamus
Modulates hypothalamic neuronal activity, improves whole body insulin sensitivit, promotes lipogenesis and peripheral fat accumulation (white adipose) and finally increases adaptive thermogenesis (brown adipose
34
How does insulin reduce hepatic glucose produciton
Acts in the ARC by inhibiting gluconeogenesis using vagal efferent nerves to the liver.
35
What two key things are needed for transduction of the reduction of hepatic glucose production
Alpha7 nicotinic receptors and IL-6 (look at picture)