Types of pharmacologically active agents

Question 1

Drug definition

Answer 1

A chemical compound that when applied to a biological system alters its function in a specific manner

Question 2

4 different types of drug target

Answer 2

Receptors, ion channels, carriers or transporters and enzymes

Question 3

Different types of pharmacologically active agent + definition

Answer 3

Exogenous- agent that originates outside of the body, such as drugs

endogenous- agent that originates from within a system, such as an organism, tissue or cell and includes hormones and neurotransmitters

Question 4

Examples of endogenous agents

Answer 4

• hormones
• neurotransmitter
• vasoactive compounds
• growth factors

Question 5

Example of vasoactive factor + explained

Answer 5

Endothelin

- endothelins are peptides with receptors all over the body that constrict blood vessels and raise blood pressure.

Question 6

Examples of exogenous agents

Answer 6

• drugs

- pathogens

Question 7

What do all these agents have in common?

Answer 7

All act upon specific complementary receptors

Question 8

Role of exogenous agents

Answer 8

Modify the effect of endogenous agents

Question 9

Different types of exogenous agent

Answer 9

agonist- drug that combines with the receptor (for an endogenous agent) to produce a response

antagonist- drug that combines with the receptor (for an endogenous agent) without producing a response

Question 10

Different ways antagonists can work

Answer 10

• physiological- bind to endogenous receptor

- effects on release, metabolism or reuptake

Question 11

Receptor definition

Answer 11

Sensing element in the system of chemical communications that coordinates the function and responses of all the different cells in the body, the chemical messengers being the various hormones, transmitters and other mediators

Question 12

Different way drugs that act on enzymes work

Answer 12

competitive inhibitor- normal reaction inhibited

non-competitive inhibitor- normal reaction inhibited- aspirin working on cycloxygenase.

false substrate- drug molecule undergoes a chemical transformation to form an abnormal product that subverts the normal metabolic pathway

prodrug- drug is degraded by enzymes to convert them from an inactive form to an active form..

Question 13

Different way drugs that act on ion channels work

Answer 13

bind to the channel protein itself- either the ligand binding site (orthosteric) or other site (allosteric) which physically plugs the channel preventing ion permeation.

indirect interaction involving an activated G protein subunit

altering the level of expression of ion channels on the cell’s surface

Question 14

Examples of drugs that act upon ion channels

Answer 14

benzodiazepines- bind to GABAa and facilitate the opening of the channel by the inhibitory neurotransmitter GABA

dihydropyridine- inhibit the opening of L-type calcium channels

Gabapentin- reduces the insertion of neuronal calcium channels into the plasma membrane

Question 15

Affinity definition

Answer 15

chemical forces involved in the association of a drug with the receptor

Question 16

Efficacy definition

Answer 16

ability of a drug to activate the receptor and produce a response

Question 17

What is occupation determined by?

Answer 17

affinity

Question 18

What is activation determined by?

Answer 18

Efficacy

Question 19

What do agonists have?

Answer 19

Both affinity and efficacy, in varying amounts

Question 20

What do antagonists have?

Answer 20

no efficacy but high affinity