Drug-Receptor Interactions

Question 1

What is a drug?

Answer 1

A chemical that interacts with a biological system to produce a physiological effect. Although all drugs are chemicals, not all chemicals are drugs.

Question 2

What are four principle protein targets with which drugs can interact?

Answer 2

Enzymes, membrane carriers , ion channels and receptors.

Question 3

What are receptors?

Answer 3

Receptors are macromolecules that participate in chemical signalling both between and within cells.

Question 4

Receptors can be subdivided into four main classes:

Answer 4

1. Ligand gated ion channels
2. G protein coupled receptors
3. Ligand-Regulated Transmembrane Enzymes
4. Including Receptor
5. Tyrosine Kinases
6. Enzyme Receptors
7. Intracellular receptors

Question 5

What are ligands?

Answer 5

Molecules (eg, drugs, hormones, neurotransmitters) that bind to a receptor are called ligands

Question 6

Types of Ligand gated ion channels

Answer 6

1. g-amino butyric acid (GABA)
2. Glycine
3. Aspartate
4. Glutamate
5. Acethylcholine
6. Serotonin

Question 7

What is an agonist?

Answer 7

An agonist is a drug that binds to the receptor and causes the same reaction as the intended chemical and receptor.

Question 8

Types of agonists?

Answer 8

Endogenous, exogenous, physiological, superagonists, full, partial, inverse, irreversible, selective, and co-agonists

Question 9

Agonists initiate changes in

Answer 9

Agonists initiate changes in second messengers

Question 10

What is an antagonist?

Answer 10

An antagonist is a drug that binds to the receptor either on the primary site, or on another site, which all together stops the receptor from producing a response

Question 11

How many types of antagonists are there and what are they?

Answer 11

There are two types of antagonism: competitive (reversible, surmountable) and non-competitive (irreversible, insurmountable)

Question 12

What is drug solubility?

Answer 12

Ability of a drug to combine with a particular type of receptor

Question 13

Two factors that determine the effect of a drug on physiologic processes are

Answer 13

1. Affinity
   2.Intrinsic activity

Question 14

What is Efficacy ?

Answer 14

Simply put, the size or strength of a response elicited by a specific agonist in a specific tissue.

Question 15

What is a drug affinity?

Answer 15

Affinity can be defined as the extent or fraction to which a drug binds to receptors at any given drug concentration or the firmness with which the drug binds to the receptor.

Question 16

What is Intrinsic activity?

Answer 16

Intrinsic activity is a measure of the ability of a drug once bound to the receptor to generate an effect activating stimulus and producing a change in cellular activity.

Question 17

The binding of a drug to a receptor is determined by what forces?

Answer 17

1. Hydrogen bonds
2. Ionic bonds
3. Van der Waals forces
4. Covalent bonds

Question 18

Which of the following is a type of drug-receptor protein that is located in cytoplasm and includes thyroid and steroid hormone receptors?

Answer 18

Transcription factors are located in cytoplasm; vitamin D and steroid and thyroid hormones are examples.

Question 19

What type(s) of drug-receptor is located in the cell surface membrane?

Answer 19

G-protein—coupled receptors, multisubunit ion channels, and protein kinases are located in the cell surface transmembrane.

Question 20

Receptor upregulation and downregulation affect which dimension of drug functioning?

Answer 20

Receptor upregulation and downregulation affect adaptation to drugs (eg, desensitization, tachyphylaxis, tolerance, acquired resistance, postwithdrawal supersensitivity).

Question 21

What is an example of competitive antagonism?

Answer 21

Naloxone (an opioid receptor antagonist that is structurally similar to morphine), when given shortly before or after morphine, blocks morphine’s effects. However, competitive antagonism by naloxone can be overcome by giving more morphine.

Question 22

What are Antagonists?

Answer 22

competitive and non-competitive

Question 23

What are the f two types of antagonism?

Answer 23

Competitive and non-competitive

Question 25

What is Efficacy ?

Answer 25

Simply put, the size or strength of a response elicited by a specific agonist in a specific tissue.

Question 26

What is an antagonist?

Answer 26

An antagonist is a drug that binds to the receptor either on the primary site, or on another site, which all together stops the receptor from producing a response