Lecture 9

Question 1

How does cyclic AMP exert the majority of its actions

Answer 1

Through cyclic AMP-dependent protein kinase (PKA or A-kinase). When it binds to the R subunit the other subunits dissociate leaving the catalytic active site open.

Question 2

What are some examples of secondary messengers

Answer 2

cyclic AMP
IP3 + DAG
PIP3

Question 3

How does cyclic AMP work

Answer 3

It increases the activity of PKA

Question 4

Describe the structure of PKA

Answer 4

It has C and R subunits. C is the catalytic subunit. The R subunit is the regulatory subunit.

Question 5

What effect can be had by activating adenylyl cyclase

Answer 5

Generates more molecules of cAMP so more PKA is activated so a greater amplitude of response.

Question 6

Describe inotropy in the heart

Answer 6

Both adrenaline and noradrenaline interact with β1-adrenoceptors to increase force of contraction.
Noradrenaline can interact with α1-adrenoceptors.