Drugs And Receptors

Question 1

What are the two overarching mechnisms that drugs can use?

Answer 1

Blocking the action of an endogenous ligand, an angoist, or activate a receptor (antagonist)

Question 2

What is the binding of drugs goverened by?

Answer 2

The laws of mass assoicaation, the drugs must have affinity for a receptor

Question 3

What are the two things nesscary for the activation of a receptor?

Answer 3

Affinity and intrinsic efficacy

Question 4

What are the features of anatgnoists?

Answer 4

Only have affinity, no efficacy

Question 5

What is effiacy/

Answer 5

The ability of a drug to illicit a respone in a tissue, a combination of intriinisc efficacy and tissue dependant factors

Question 6

How would you measure drug binding?

Answer 6

Using a radioactively labelled ligand to find Kd, o Pharmologically to determine Ka.

Question 7

What is Kd?

Answer 7

Kd is the dissociation constant, which is where 50% of the receptors are occupied by drug, and is a measure of the affinity

Question 8

What does a low value of Kd indicate?

Answer 8

A higher affinity for the drug

Question 9

How would you demonstraate the functional measurable response of a drug?

Answer 9

Shown by concentration response or dose response curves

Question 10

What is the difference between concentration and dose?

Answer 10

Concentrtion refers to when the drug is used agaisnt a single cell, whereas dose refers to when the drug is used on a entire animal

Question 11

What is EC50?

Answer 11

The concentration of drug where you achieve 50% of the maximal response

Question 12

What governs the value of EC50?

Answer 12

Affinity, intrinsic efficacy, and tissue dependant events, therefore the whole efficacy

Question 13

What is EC50 a measure of?

Answer 13

Potentancy

Question 14

What is Potency>

Answer 14

A combination of the affinity and efficacy of a drug

Question 15

What are the different aspects of a drug?

Answer 15

Affinity and efficacy (and thereby potency) selectivity, drug metabolism, physicochemical affects.

Question 16

What are the two common asthma drugs and the receptor tht they target?

Answer 16

Salbutamol and salmetral, and they target the B2 Adrenoreceptor which is involved in relaxation of the lungs.

Question 17

What is the specificity of salbutamol to the B2 adrenreceptor?

Answer 17

It has a Kd of 20 um for B2 and 1um for B1, which is poor, however a low efficacy for B2 receptors makes it useful within treatment

Question 18

What are is the specificity of salmetral to the B1 Adrenoreceptor?

Answer 18

It is 3455x more specific to B1, however, it has the same intrinsic efficacy on both receptors

Question 19

Why is it important asthma drugs are specific to B1 adrenoreceptors?

Answer 19

As B2 adrenoreceptors are found on the heart and can increase heart rate, which can lead to angina.

Question 20

What are the most common targets for drugs?

Answer 20

Proteins (enzymes in 47% of cases, or g protein coupled receptors)

Question 21

How does receptor number influence potency?

Answer 21

A greater number of filled receptors generally increases potency of the drug, however, you may not need all of the receptors filled to achieve a maximal response.

Question 22

Why would you have spare receptors on a tissue/

Answer 22

Increase sensitivity, allowing response at low amounts of angoist, and you can change the amount of receptors to alter the sensitivity to a drug

Question 23

Describe one of the contributing factor in developing tolerance to drugs.

Answer 23

Tissues adapting by reducing the number of receptors, so that you cannot achieve the same maximal response

Question 24

What is a partial agonist?

Answer 24

Some drugs can produce the full response even with the maximal receptor filling system, (they are often less good at inducing the active state of a receptor.)

Question 25

What is the relationship between EC50 and Kd in a partial angoist?

Answer 25

EC50 is equal to Kd

Question 26

What is the intrinsic activity of a partial angoist when compared with a full agnoist?

Answer 26

They have a lower intrinsic activity (often have the same efficacy))

Question 27

What is the clinical relevance of partial agnoism?

Answer 27

They allowed a more controlled response to certain drugs, can be used in treating addiction to heronin (bueprnonmorphine)

Question 28

How is bueprenanmorphine used in treating a heron in addiction?

Answer 28

Has a higher affitnity but lower efficacy that heronin,acts at the same u-opoid receptors if given instead or heronin at first can cause severe withdrawal symptoms due to the partial agonism, can be used to help enable gradual withdrawal

Question 29

What are the three types of antagonism that drugs can perform?

Answer 29

Irreversible competitive antagonism, reversible competitive antagonism, and non competitive antagonism

Question 30

What is the mechanism of irreversible competitive antagonism?

Answer 30

Relies on the equlibrumm between the receptor and the molecule, causes a parelle shifit to the right of the dose response curve and is surrmountable

Question 31

What is a example of a drug that uses reversible competitive antagonism?

Answer 31

Naloxene, is. High affinity competitive anatagonist at the u-opioid receptor, and can be used to treat opioid overdose.

Question 32

What is the mechanism of irreversible competitive antagonism?

Answer 32

Is where the antagnoism diffuses away slowly if at all, and causes a parallel shift to the right of the dose response curve, and at a higher concentration helps to suppress the maximal response.

Question 33

Give two example of drugs that are irreversible competitive anatgnoists.

Answer 33

Plavix, used to treat thrombosis, and phenoxybenazmine, is a non selective irreversible adrenoblocker used to treat vascontriction in the production of excessive adrenaline by tumours of the adrenal cells.

Question 34

What is the mechanism of non competitive antagonism?

Answer 34

Bind at allosteric sites, and have similar effects to irreversible competitive antagonism

Question 35

What are examples of drugs that work by irreversible competitive antagonism?

Answer 35

Cinclet, and a maravian.