Module 3

Question 1

What triggers the conformational change in GPCRs?

Answer 1

Binding of an agonist

Question 2

What happens to the alpha subunit of a GPCR upon activation?

Answer 2

GTP replaces GDP - the alpha subunit dissociates and activates a target protein

Question 3

What are the two major enzymes activated by GPCRs to amplify signals?

Answer 3

Adenylyl cyclase and phospholipase C

Question 4

What secondary messenger is produced by adenylyl cyclase?

Answer 4

cAMP

Question 5

What does cAMP activate?

Answer 5

Protein kinase A (PKA)

Question 6

What are the products of phospholipase C activity?

Answer 6

DAG and IP3

Question 7

What does IP3 do in the cell?

Answer 7

Increases intracellular Ca²⁺ from the ER

Question 8

What does DAG activate?

Answer 8

Protein kinase C

Question 9

Which G protein subtype is associated with D2 dopamine receptors?

Answer 9

Gi

Question 10

What is the effect of Gi activation?

Answer 10

Decrease cAMP, opens K⁺ channels, closes Ca²⁺ channels

Question 11

Which G protein subtype is associated with D1 dopamine receptors?

Answer 11

Gs

Question 12

Which drug combination results in attenuated (weakened) interaction?

Answer 12

Beta blocker and alpha-2 agonist

Question 13

Why is L-Dopa combined with carbidopa?

Answer 13

To inhibit dopamine breakdown outside the brain

Question 14

How does amphetamine increase dopamine and NA levels?

Answer 14

By reversing reuptake transporters and vesicular storage

Question 15

What is required for NRDIs to work effectively?

Answer 15

Natural release of dopamine/noradrenaline

Question 16

What does methylphenidate inhibit?

Answer 16

NET and DAT

Question 17

What is the mechanism of enzyme inhibitors like monoamines?

Answer 17

Prevent breakdown of monoamines → increase receptor activation

Question 18

What type of antagonist is propranolol?

Answer 18

Non selective Beta 1 and Beta 2 antagonist

Question 19

What is the function of a2 agonists in the CNS?

Answer 19

Inhibit NA release from the locus coeruleus - can enhance cognition

Question 20

What second messengers are produced my M3 receptor activation?

Answer 20

IP3 and DAG

Question 21

What is the physological effect of M3 receptor activation in muscle tissue?

Answer 21

Smooth muscle contraciton

Question 22

What is the difference between full and partial agonists?

Answer 22

Full agonists reach maximum response, partials do not

Question 23

Give an example of a full and partial agonist affecting heart rate

Answer 23

Adreanline (~200BPM), Xamoterol (~110BPM)

Question 24

Which drug class is likely to cause the most side effects?

Answer 24

A - releasing agents

Question 25

What receptor do benzodiaepines modulate?

Answer 25

GABA-A

Question 26

What is the mechanism of action of benzodiazepines?

Answer 26

Increase frequency of GABA-A channel opening → hyperpolarisation

Question 27

Where does dopamine originate in the brains reward system?

Answer 27

Ventral tegmental area (VTA)

Question 28

Why are injected dopamine-releasing agents more addictive than oral?

Answer 28

Activate D1receptors more stongly via phasic release

Question 29

What does caffiene do to adenosine receptor activity?

Answer 29

Blocks A1 receptors → reduces A1 activity

Question 30

In which state does caffeine have a greater pharmacological effect?

Answer 30

Sleep deprived state due to higher adenosine levels

Question 31

How does caffeine affect executive control in rested vs. sleep-deprived states?

Answer 31

Improved in both, but more significantly in sleep-deprived (effect size ~1.95)

Question 32

What are caffeine’s effects on reaction time and driving performance when sleep-deprived?

Answer 32

Both significantly improved