Pharmacodynamics

Question 1

What is Pharmacodynamics?

Answer 1

what the drug does to the body, the actions of the drugs and side effects

Question 2

What are the 4 cellular protein targets of drugs?

Answer 2

1 - receptors
2 - enzymes
3 - ion channels
4 - carrier proteins

Question 3

Where are the the 4 protein targets found?

Answer 3

In the lipid bilayer

Question 4

What is a LIGAND

Answer 4

a substance that binds to a receptor to serve a biological purpose

Question 5

What are the 5 types of ligand that can bind to a receptor?

Answer 5

Agonist - activated receptor

Antagonist - blocks receptor

Partial agonist - activates it but less

Non-competitive antagonist - bind irreversibly; decreases number of receptors available for binding

Competitive antagonist - bind is reversible, if agonist and antagonist have same affinity, receptor will bind to whichever has the highest concentration.

Question 6

Define POTENCY

Answer 6

concentration of drug required for a response

Question 7

Define AFFINITY

Answer 7

Strength of attraction between drug and receptor

Question 8

Define EFFICACY

Answer 8

ability once bound to initiate changes that leads to an effect

Question 9

Describe an example of an ANTAGONIST receptor drug

Answer 9

PROPANOLOL:
-Beta antagonist
- blocks beta 1 so adrenaline (ligand) can’t bind.
- Lowers BP/HR

Question 10

Example of a BETA AGONIST

Answer 10

SALBUTAMOL:
- mimics adrenaline to induce fight or flight
- the body’s response is to open/dilate bronchioles and helps asthma attacks

Question 11

Example of RECEPTOR DRUG

Answer 11

SUDAFED:
-mimics adrenaline to unblock sinuses
- Causes many side effects due to the concentration vs. size of area requiring affect.

Question 12

Drug example of agonist, antagonist and partial antagonist

Answer 12

Heroin - agonist
buprenorphine - partial antagonist
Naloxone - Antagonist

Question 13

Example of enzymes as drug targets

Answer 13

NSAID’s:
- they bind and inhibit COX enzyme
- COX enzymes catalyse the production of prostaglandins that modulate inflammation

Question 14

Example of a drug that inhibits enzymes

Answer 14

RAMIPRIL:
ACE inhibitor; drug binds to anigiotensin 2
AT2 is a vasoconstrictor
by binding to this, it causes vasodilation and lowers BP
used in cardiac patients

Question 15

what are ion channels?

Answer 15

Gaps in cell membranes that control the movement of electrolytes in and out of the cell

Question 16

What are the 4 main ions/electrolytes

Answer 16

Sodium (NA+)
Potassium (K+)
Calcium (Ca+)
Chloride (Cl -)

Question 17

What are the TWO types of ion channels?

Answer 17

Voltage Gated: open and close in response to action potentials

Ligand Gated: open and close in response to chemical messengers

Question 18

Example of a drug acting on an ion channel

Answer 18

CALCIUM CHANNEL BLOCKER(Amlodipine)
- Ca+ ion channel regulates influx of Ca+ into muscles, causing muscle contraction
- CCB is used to reduce muscular resistance, lowering BP

Question 19

Example of a LIGAND-GATED ion channel using GABA

Answer 19

GABA acts to reduce excitability in the CNS.
Benzodiazepines bind to a separate binding site and act as a positive modulator(increase effect of GABA) to stop/control seizures.

Question 20

Example of a LIGAND-GATED ion channel using SSRI’s

Answer 20

Selective Serotonin uptake inhibitors inhibit the update of serotonin in the synapses in brain
- from taking these, it increases amount of serotonin, meaning more is waiting to cross the synapse.
- more serotonin receptors have to be made on the post-synapse to receive all the extra serotonin from the pre-synapse.