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Flashcards in Biochemistry Deck (8):
1

What tells capillaries to increase?

Astrocyte signals leads to breakdown of phospholipids --> arachidonic acid (AA) which can make prostaglandins like HETE (constriction) and EETs (dilation)
-Low O2 promotes vasodilation

2

What is the significance of the Astrocyte-Neuron Lactate Shuttle (ANLS)?

Shuttles glucose --> lactate to the brain.
-If this shuttle is defective, you won't know until child stops breast feeding and gets off ketone diet. Then child will not get enough glucose to the brain
-Hypoglycorrhachia = low glucose in CSF

3

What is used when glucose in unavailable? Why would glucose be unavailable to the brain?

KETONES (D-3-hydroxybutyrate & Acetoacetate)
-Used in extreme starvation & fasting, Hibernation, Neonates, Suckling (mother's milk = mostly fat)
-These are a good alternative to glucose bc it requires less oxygen (28% less) to make ATP

4

What is a risk factor for AD?

Leaky blood vessels. They allow more things to cross the BBB, which exposes brain to toxic chemicals and leads to cognitive degeneration.

5

What area of the brain is affected by AD a lot? What about it?

Hippocampus (memory)
-Barrier permeability in hippocampus increases with aging but not so much in other regions
-In AD increased permeability in hippocampus is much more severe than just aging!

6

What are the different proteins associated with tight junctions? What do these junctions do?

-Occludin
-Claudin
-JAM (juncitonal adhesion molecule)
-Helps from BBB - makes up contact/blocking between two cells

7

What substances can get into the brain from the blood?

Lipophilic substances like alcohol, ethanol (also cocaine, THD <-- all lipid soluble)

8

What is the significance of MCT-1?

Monocarboxylate Transporter - 1
-Transport protein that movement lactic acid from in to out
[lactic acid, acetate, butyrate, Ketones (D-beta-hydrocybutyrate & Acetoacetate)
-This transporter is located right on the brain capillaries!