Trigger 7 (TBI) Gliovascular unit

Question 1

What cells are involved in the gliovascular unit and type of junction?

Answer 1

astrocytes, pericyte and tight junctions

Question 2

By what process does water move across the BBB?

Answer 2

Paracellular acqueous pathway:

water soluble agents move through tight junctions

Question 3

How does lipid soluble agent move through the brain?

Answer 3

they diffuse through endothelial cells

Question 4

What kind of proteins do transport proteins move across the BBB and can you give examples of the receptors?

Answer 4

Glucose (GLUT 1), amino acids (LAT 1) and nucleosides (EAAT1-glutamate)

Question 5

Receptor mediated transcytosis moves what two common signalling molecules?

Answer 5

insulin and transferrin

Question 6

What process moves albumin and other plasma proteins across the BBB

Answer 6

adsorptive transcytosis:

vesicles envelop proteins and transport across membrane

Question 7

When BBB become leaky and astrocytes become damaged, what signalling molecule to they release

Answer 7

S100

Question 8

What 4 things do microglia interact with/release when BBB becomes leaky

Answer 8

Glutamate production, quinoloic acid and arachidonic acid and proinflammatory cytokines (IL-1beta, TNF-alpha, IL-2 and IL-6)

Question 9

Explain the steps these factors release lead to excitoxicity

Answer 9

they lead to production of free radicals.
This in term leads to the production of peroxynitrite and lipid peroxidase which, with free radicals, leads to mitochondrial dsyfunction. This causes death signals and cells to die. this results in further excitoxicity and synaptic dsyfunction