Pharmacodynamics

Question 1

Why is Pharmacodynamics important?

Answer 1

Pharmacodynamics is important for drug safety, effectiveness and dosage.

Question 1

What are the 2 essential functions of a receptor?

Answer 1

2 Essential Receptor functions: Recognition of a specific ligand molecule
Transduction of signal to a response

Question 2

Define AGONISTS

Answer 2

AGONISTS are ligands that bind to a receptor (causing a conformational change to the active conformation) and ACTIVATE a response resulting in the DESIRED effect being produced.

Question 3

Define ANTAGONISTS

Answer 3

ANTAGONISTS are ligands that bind to a receptor but DO NOT activate a response. No action is caused.

Question 4

What are the different types of AGONISTS?

Answer 4

Types of AGONISTS: FULL, PARTIAL, INVERSE

Question 5

How many types of AGONISTS are there?

Answer 5

There are 3 types of AGONISTS. FULL, PARTIAL and INVERSE

Question 6

Define INTRINSIC ACTIVITY

Answer 6

Intrinsic Activity: the ability of a drug to produce the maximal effect. The STRENGTH of the effect, effect that can be measured, STRENGTH of the drug receptor complex

Question 7

Which factors govern drug action?

Answer 7

Intrinsic activity and Affinity govern drug action.

Question 8

Define SPECIFICITY

Answer 8

Specificity: selectivity for one receptor.
Depends on the binding affinity between the ligand and the binding site on the receptor

Question 9

Define FULL AGONIST

Answer 9

Full Agonist: Agonist that has high efficacy, producing a full response while occupying a relatively low proportion of receptors.

Question 10

Define Dissociation Constant KD

Answer 10

Dissociation Constant (KD): The amount of drug bound to a receptor at equilibrium

Question 11

Define k1

Answer 11

k1: The rate at which a drug associates

Question 12

What does PAR calculate?

Answer 12

PAR : Percentage of receptors that have drugs bound to them. Occupancy. It can be calculated NOT measured.

Question 13

Define AFFINITY

Answer 13

AFFINITY: ability of a ligand to bind to a receptor. How tightly a ligand binds to a receptor.

Question 14

Define EFFICACY

Answer 14

EFFICACY: Ability to initiate events that lead to a response

Question 15

Define POTENCY

Answer 15

POTENCY: Relative amount of drug to produce an effect. Combination of AFFINITY and INTRINSIC ACTIVITY

Question 16

Define PARTIAL AGONIST

Answer 16

Partial Agonist: Agonist that is unable to produce maximal effect despite occupation of all receptors. Lower efficacy than full agonist.

Question 17

Define INVERSE Agonist

Answer 17

Inverse Agonist: Agonist that keeps receptors in inactive form. Eliminates normal “basal” activity.

Question 18

What does a small kD indicate?

Answer 18

A small kD indicates a high affinity between the drug and receptor

Question 19

Do all drugs work by binding to receptors?

Answer 19

No, not all drugs work by binding to receptors.

Question 20

Name 3 types of drugs that work without binding to a receptor

Answer 20

Antacids, Fluid Expanders and Anaesthetics work without binding to receptors

Question 21

Describe the adenosine antagonists and give an example of one

Answer 21

*Caffeine is an adenosine antagonist- similar structure to adenosine
*Adenosine antagonists facilitate dopamine release

Question 22

What are units of equilibrium dissociation written as?

Answer 22

Units of equilibrium dissociation: 1x10-8M or 10nm

Question 23

There is an ___________ relationship between the kD and the affinity

Answer 23

There is an inverse relationship between the kD and the affinity

Question 24

What is a G protein coupled receptor?

Answer 24

Integral membrane protein that contain seven transmembrane (TM) α-helices.
Largest and most diverse group of membrane receptors in eukaryotes.

Question 25

Most receptors are ___________.

Answer 25

Most receptors are PROTEINS.

Question 26

All receptors are _____________.

Answer 26

Receptors are MACROMOLECULES.

Question 27

Where are receptors usually found?

Answer 27

Receptors are usually found on the:
* Cell surface
*Cytoplasm
*Nucleus

Question 28

Receptors are ________ specific

Answer 28

Receptors are LIGAND specific

Question 29

How many types of receptors are there?

Answer 29

There are 5 types of receptors:
* Internal (intracellular receptors)
*Transmembrane (cell-surface) receptors
*Ion-channel linked receptors
*G-protein linked receptors
*Enzyme-linked receptors

Question 30

Intracellular (internal) receptors

Answer 30

Intracellular receptors:
*Found in the cytoplasm
*Respond to hydrophobic molecules
*Usually involved in gene expression

Question 31

Transmembrane (cell-surface) receptor

Answer 31

Transmembrane (cell-surface) receptors:
*Bind to external ligands
*Performs signal transduction
*Three main types: Ion-channel linked, G-protein linked, enzyme-linked