Brain Metabolism Flashcards
Is there glycogen in brain cells?
yes but very little
What type of cell modulates the blood flow through the neurovascular unit?
astrocytes
vasoconstriction/-dilation
Two functions of pentose phosphate pathway
five carbon sugars
NADPH
B1 deficiency affects which enzyme in which pathway
transketolase in pentose phosphate pathway
B1 deficiency leads to what clinical manifestation
Wernicke-Karakoff Syndrome
What is the tracer for glucose metabolism?
2-deoxyglucose
What is the astrocyte-neuron lactate shuttle?
glucose is taken from capillary into astrocyte where it is converted to lactate. the lactate then moves to the neuron where it is converted to pyruvate and burned in TCA.
What is the ATP from the Glc–>lactate rxn in the astrocyte used for?
Na+/K+ ATP (membrane potential)
glutamine–>glutamate conversion
How is glutamate recycled in a neuron?
glutamate moves from synaptic space into astrocyte where it is converted into glutamine using ATP. glutamine is then transferred into presynaptic neuron where is is converted back into glutamate.
What is the cerebral metabolic rate?
(arterial concentration - venous concentration)*(blood flow/weight)
Transketolase is an important part of which pathway in brain glucose metabolism?
pentose phosphate pathway
What cofactor does transketolase require?
vitamin B1
What is the pathological manifestation of thiamine deficiency?
Wernicke encephalopathy and Kasakoff psychosis
What is the tracer used in PET scans?
radiolabelled 2-deoxyglucose
What are the three regulated steps of glycolysis?
hexokinase
PFK
pyruvate kinase
