Drug Receptor Classes.

Question 1

What is pharmacodynamics?

Answer 1

How the properties of drugs influences their interactions with the body.

Question 2

What are the 4 main types of target for drugs?

Answer 2

Receptors.

Enzymes.

Ion channels.

Transporters.

Question 3

What happens when a drug binds to a receptor protein?

Answer 3

There will be an intracellular response e.g. a channel opens.

Question 4

Where in the body are most receptor proteins found?

Answer 4

In cell membranes.

Question 5

What happens when drugs bind to enzymes?

Answer 5

They can either induce them or inhibit them.

Question 6

Will most drugs inhibit or induce enzymes?

Answer 6

Inhibit them.

Question 7

What effect will drugs have on ion channels?

Answer 7

They will either inhibit or open the ion channels e.g. anaesthetics block sodium channels.

Question 8

What is the mode of action of drugs that act as ion channel modulators?

Answer 8

They increase or decrease the probability that an ion channel will open.

Question 9

What is the mode of action of drugs that bind to transporter proteins?

Answer 9

They can either inhibit or enhance the transport of the compound that the transporter is supposed to transport.

Question 10

What kind of ion channels will only open or close when there is a change in membrane potential?

Answer 10

Voltage gated ion channels.

Question 11

What is the refractory period for voltage gated ion channels?

Answer 11

The period where the ion channel cannot be influenced (opened).

Question 12

How do drugs affect the refractory period of voltage gated ion channels?

Answer 12

Most drugs will increase the refractory period of these channels.

Question 13

What are 4 types of drugs that activate voltage gated ion channels?

Answer 13

Local anaesthetics.

Antu epileptics.

Anti dysrhythmics.

Drugs that affect the release of neurotransmitters.

Question 14

How are ligand gated ion channels activated?

Answer 14

They open when a particular molecule binds to a receptor on these channels.

Question 15

How do drugs get ligand gated ion channels to open?

Answer 15

A drug can be made to resemble the ligand and this will cause the channel to open.

Question 16

How do drugs affect ligand gated ion channels.

Answer 16

They increase the opening frequency of these channels or modify the time that these channels are open for.

Question 17

What happens when an ion channel opens?

Answer 17

Ions rush into or out of the cell and this changes the membrane potential and leads to a response.

Question 18

What are 3 examples of ligand gated ion channels?

Answer 18

Nicotinic receptors.

GABA receptors.

Glutamate receptors.

Question 19

What receptors are coupled to a G protein?

Answer 19

GPCR receptors.

Question 20

What happens when a drug binds to a GCPR receptor?

Answer 20

The Gi, Go or GQ protein will be activated.

Question 21

What are the 4 classes of G protein that are found in GCPRs?

Answer 21

Gi proteins.

G0 proteins.

GQ proteins.

GS proteins.

Question 22

What determines the intracellular responses following the activation of a GCPR?

Answer 22

The type of G protein that is activated.

Question 23

What is the role of Gi/G0 G proteins following activation of a GCPR?

Answer 23

They inhibit the enzyme adenylate cyclase and this causes a decrease of cAMP in the cell.

Question 24

What happens in a GCPR once adenylate cyclase has been inhibited by the Gi/G0 protein?

Answer 24

There is an increased outflow of potassium ions and an increased influx of calcium ions.

This changes membrane potential.

Question 25

What are 3 examples of a GI/G0 GCPR?

Answer 25

Muscarinic M2 receptors.

Alpha-2 adrenoceptors.

Serotonin receptors.

Question 26

What happens when GQ GCPRs are activated?

Answer 26

The GQ proteins activates phospholipase C which leads to an increase in insP3 and calcium ions within the cell.

Question 27

What happens in GQ GCPRs after the GQ protein has lead to an increase of insP3 and calcium ions within the cell?

Answer 27

It leads to the conversion of PIP-2 to DAG and this results in an increase in protein kinase C.

Question 28

What are 4 examples of GQ GCPRs?

Answer 28

Alpha-1 adrenoceptors.

Muscarinic M1 and M3 receptors.

Serotonin receptors.

Histamine H1 receptors.

Question 29

What happens when a GS GCPCR is activated?

Answer 29

The GS protein activates adenylate cyclase and this leads to an intracellular increase of cAMP.

Question 30

What determines how long the drug takes to have an effect?

Answer 30

The type of receptors that are used by drugs.

Question 31

What are examples of GS GCPR receptors?

Answer 31

Beta adrenoceptors.

Serotonin receptors.

Dopamine receptors.

Histamine H2 receptors.

Question 32

When are kinase linked receptors activated?

Answer 32

When a particular ligand binds to the receptor.

Question 33

What happens in a kinase linked receptor once it has been activated by a ligand?

Answer 33

There will be protein phosphorylation and this leads to gene transcription.

Question 34

What can be made following gene transcription?

Answer 34

Proteins.

Question 35

Will drugs that affect kinase linked receptors have very quick effects?

Answer 35

There is a long time between administration of these drugs and any visible effects.

Question 36

Where are nuclear receptors located?

Answer 36

In the nucleus.

Question 37

What must drugs that travel to nuclear receptors be able to do?

Answer 37

Enter the cell and bind to DNA within the nucleus.

Question 38

What are 2 common drugs that bind to nuclear receptors?

Answer 38

Glucocorticoids/corticosteroids.

Question 39

What effects can drugs that bind to nuclear receptors have?

Answer 39

Gene activation and gene repression