Lecture 8 (Respiratory channelopathies 1)

Question 1

How common is cystic fibrosis?

Answer 1

1 in 20

Question 2

Which ion channel defect causes cystic fibrosis?

Answer 2

cAMP activated Cl- channel

Question 3

What are the effects of cystic fibrosis? (5)

Answer 3

-Male infertility
-Liver disease
-Respiratory disease
-Distal intestinal obstruction syndrome
-Pancreatic insufficiency

Question 4

What is a CFTR?

Answer 4

Cystic fibrosis transmembrane conductance regulator (CFTR)

Question 5

How does a cAMP activated Cl- channel open?

Answer 5

cAMP phosphorylates protein kinase A
This opens Cl channel

Question 6

What is NMD?
and what is the function of it?

Answer 6

-NMD = nonsense mediated decay
-NMD is protection method of cell, detects genetic code as mutant so doesn’t make CFTR protein

Question 7

Why is viscous airway mucus dangerous in CF?

Answer 7

Mucus trapping bacteria, thicker and more vicious in CF, not cleared effectively or clearly along with bacteria

Question 8

What drives height in the airways?

Answer 8

Balance of Na and Cl drives height
More Na goes down, more Cl goes up

If height is efficient, good clearance of mucus and bacteria
In CF not cleared properly

Question 9

What do CFTR and ENaC do in airway cells?

Answer 9

Chloride secreted due to CFTR; this drives water between cells
ENaC absorbs Na

Question 10

What is the relationship between CFTR and ENaC?

Answer 10

When CFTR high ENaC is low and vice versa, inhibit each other
In CF we lose ENaC inhibition, even more ENaC function

Question 11

What are treatments are used in CF patients for airways? (4)

Answer 11

Physiotherapy - displace mucus

Bronchodilator drugs – opens up airways

Antibiotics (Steroids) – for infection

Mucolytics (e.g. Dnase) - break down mucus

Question 12

What are other treatment for CF? (4)

Answer 12

-Exersize
-Antibiotics
-High energy supplements
-Gene therapy