Drug & Receptor Interactions

Question 1

What is a receptor?

Answer 1

A protein that responds to a stimulus and transmits chemical signals to produce a response

Question 2

What is a ligand?

Answer 2

An ion/molecule that forms a complex with a another molecule

Question 3

What is a prodrug?

Answer 3

A compound that must undergo chemical conversion by metabolic processes before becoming an active pharmacological agent.

Question 4

Give an example of a prodrug and how it works

Answer 4

Diamorphine - when it enters the brain it is converted into morphine which binds to mu opioid receptors

Question 5

Define bioavailability

Answer 5

Extent and rate at which the active drug enters systemic circulation

Question 6

Define affinity

Answer 6

How tightly a drug binds to its receptor

Question 7

Define efficacy

Answer 7

The capacity of a drug to produce a change in a target cell/organ after binding to a receptor

Question 8

Define potency

Answer 8

A measure of the amount of drug required to produce an effect of given intensity

Question 9

What is an agonist?

Answer 9

A neurotransmitter/drug that mimics the action of a neurotransmitter and binds to its receptor

Question 10

Agonists have a _____ affinity for its own receptor and can produce an _______ or ______ effect of the post-synaptic neuron

Answer 10

high
excitation
inhibition

Question 11

Partial agonists produce a higher/lower response than a partial/full agonist after binding

Answer 11

lower

full

Question 12

What is an inverse agonist?

Answer 12

A ligand that binds to the same receptor binding site as an agonist

Question 13

An agonist increases/decreases the activity of a receptor above its basal level.
An inverse agonist increases/decreases the activity of a receptor below its basal level.

Answer 13

increases

decreases

Question 14

What can block the effects of agonists and inverse agonists?

Answer 14

antagonists

Question 15

What is an antagonist?

Answer 15

A drug that has affinity for a neurotransmitter receptor and prevents the action of a neurotransmitter to bind to its own receptor

Question 16

What is an inhibitor?

Answer 16

A molecule that binds to another e.g. enzyme and decreases its activity.

Question 17

Give 2 ways in which some drugs inhibit activity of a neuron

Answer 17

• hyperpolarization of neuron

- blockade of binding of a neurotransmitter to its own receptor

Question 18

Give an example of agonists that inhibit the postsynaptic neuron

Answer 18

GABA
Diazepam
Morphine

Question 19

Give an example of an antagonist that inhibits the influx of Ca2+ ions

Answer 19

Nifedipine

Question 20

Give an example of an antagonist that inhibits the B1-adrenergic receptor

Answer 20

atenolol - beta blocker

Question 21

What causes disinhibition?

Answer 21

The inhibition of the inhibitor

Question 22

Describe how the release of endorphin can cause the excitation of synaptic transmission through disinhibition of GABAergic inputs

Answer 22

• opioidergic neuron is depolarised
• endorphin is released which binds to opioid receptors on GABA
• The activation of the receptors causes hyperpolarisation of GABA
• GABA neuron stops exerting an inhibitiory control over dopamine
• The dopamine neuron can fire and release dopamine

Question 23

What is the collective name of the 3 protective membranes that cover the skull?

Answer 23

meninges

Question 24

What are the 3 layers of the meninges called?

Answer 24

• dura mater
• arachnoid layer
• pia mater

Question 25

List the 3 main functions of the meninges

Answer 25

- protection - blood supply - gives space for the flow of cerebrospinal fluid

Question 26

Describe how the blood brain barrier maintains a neutral environment

Answer 26

- regulates passage of molecules in/out | - protects brain from microorganisms and toxins circulating in the blood

Question 27

What are the 2 main pairs of arteries that the brain relies on for its blood supply?

Answer 27

- internal carotid arteries | - vertebral arteries

Question 28

What part of the brain do the internal carotid arteries supply blood to?

Answer 28

anterior brain

Question 29

What part of the brain do the vertebral arteries supply blood to?

Answer 29

posterior brain | brainstem

Question 30

What happens to the brain when it is without O2 and important nutrients?

Answer 30

- brain cells are damaged/ die within minutes | - damage leading to physical/cognitive/mental disabilities

Question 31

What term refers to the blood flow in the brain?

Answer 31

Cerebrovascular

Question 32

Define Cerebral blood flow (CBF)

Answer 32

the blood supply to the brain in a given time

Question 33

What is an adults typical CBF?

Answer 33

750mL/min or 15% of CO

Question 34

What term describes too much blood flow?

Answer 34

hyperemia

Question 35

What can hyperemia lead to?

Answer 35

intracranial pressure (ICP)

Question 36

List the 3 purposes of the cerebrospinal fluid (CSF)

Answer 36

- buoyancy against gravity - protection - from brain striking cranium when jolted - chemical stability

Question 37

The brain and CSF are similar in ________, which makes the brain float in neutral ________ suspended in CSF

Answer 37

density | buoyancy

Question 38

What cells of the choroid plexus produce the CSF ?

Answer 38

ependymal cells