Brain Metabolism

Question 1

describe the uptake of glucose and ketone bodies into the brain

Answer 1

• uptake occurs by specific facilitated diffusion channels that are NOT insulin dependent
  
  • GLUT-1
  • GLUT-3 into neurons
• ketone bodies use the monocarboxylate transporter
  
  • shared with pyruvate, lactate, acetate
• during starvation, the KB transporter is upregulated

Question 2

name the 3 rxns requiring vitamin B1

Answer 2

• pyruvate dehydrogenase
• a-KG DH
• BCAA DH

Question 3

which test is used to determine vit B1 deficiency?

Answer 3

transketolase assay

Question 4

describe the 2 forms of thiamine deficiency

Answer 4

Wernicke-Korsakoff syndrome and BeriBeri

Question 5

describe Wernicke-Korsakoff syndrome

Answer 5

• B1 deficiency
  
  • responds to thiamine supplement
• due to alcohol abuse in Western societies
• mental confusion
• ataxia
• ophthalmoplegia

Question 6

myelin has a high content of ____ and _____

Answer 6

myelin has a high content of sphingomyelin and cerebrosides

Question 7

describe the normal prion protein (PrP)

Answer 7

the normal prion protein (PrP) is soluble and anchored to the extracellular side of neuronal membranes

Question 8

describe the misfolded form of PrP

Answer 8

the misfoled PrPsc (infections form) is able to convert PrP (normal form) to the infectious form

PrPsc is insoluble -> forms plaques on neurons

Question 9

the normal PrP has no ____ and mainly ____

the PrP^sc has many _____

Answer 9

the normal PrP has no B-sheets and mainly alpha-sheets

the PrP^sc has many B-sheets

Question 10

contrast prion disease vs Alzheimer’s

Answer 10