Drugs And The BBB

Question 1

What are the 3 barriers of the CNS ?

Answer 1

BBB
- separates brain tissue from blood vessels

Blood-CSF barrier (BCSFB)

• separates CSF from blood vessels
• site where CSF is produced from choroid plexi

Arachnoid mater/membrane barrier
- separates the CSF in subarachnoid space from blood vessels

Question 2

Primary differences between peripheral capillaries and the BBB capillaries

Answer 2

periphery

• highly permeable
• fenestrations are present
• possess pinocytotic vesicles to promote trans cellular transport

BBB

• possess tight junctions and are non-permeable
• few pinocytotic vesicles
• possess pericytes and astroglial to further protect unwanted permeability

Question 3

Where are ependymal cells located?

Answer 3

In the BCSFB

Specialized cells that are used to generate CSF and also transport blood to and from the CSF

Drugs that need to enter CSF, must pass through choroid plexus first.

Question 4

Why is levodopa used in Parkinson’s rather then just straight dopamine

Answer 4

L-DOPA can cross the BBB and then be metabolized into dopamine

Dopamine itself cannot

Question 5

What is the transport protien for L-DOPA?

Answer 5

L-neutral amino acid transporter (LNAA)

Question 6

Differences between bacterial, viral, fungal and TB meningitis

Answer 6

Viral

• lowWBC count (but still elevated)
• primarily lymphocytes
• mild elevation of protein
• normal glucose

Bacterial

• higher WBC count
• primarily neutrophils
• moderate-high elevation of protein levels
• low glucose and decreased CSF/glucose ratio

Fungal

• low WBC count (but still elevated)
• primarily lymphocytes
• moderate-high elevation of protein levels
• low glucose and decreased CSF/glucose ratio

TB

• low WBC count
• no primary dominance of WBC
• moderate-high elevation of protein levels
• low glucose and decreased CSF/glucose ratio