Receptors

Question 1

Agonist definition

Answer 1

Binds to receptor producing a cellular response

Question 2

Antagonist definition

Answer 2

Prevent response of agonist

Question 3

Allosteric agonist definition

Answer 3

Binds to the allosteric site to regulate the activity of the receptor by altering the affinity of the orthosteric site

Question 4

Give an example of an allosteric agonist

Answer 4

Benzodiazepine
Positive allosteric modulator of the GABA a receptor
Increases receptors orthosteric site affinity for GABA

Question 5

Name the four families of receptors

Answer 5

1. ligand gated ion channel (ionotropic)
2. G-protein coupled receptor (metabotropic)
3. Kinase linked receptor
4. nuclear receptor

Question 6

Which is the fastest acting receptor and why?

Answer 6

Ligand gated ion channel
Specialised for rapid signalling due to rapid action of ions

Question 7

How many subunits does a G-protein coupled receptor have?

Answer 7

7 transmembrane domains

Question 8

What is the definition of a drug?

Answer 8

A chemical of known structure when administered to an organism has a biological effect (good or bad)

Question 9

Definition of medicine

Answer 9

chemical prep. containing one or more drugs administered to produce a therapeutic effect

Question 10

Name 4 types of biopharmaceuticals

Answer 10

Proteins- copies of endogenous proteins
Oligonucleotides- induce production of proteins
Gene therapy- addition genetic material to cells to prevent/ alleviate
Regenerative medicine- engineered stem cells to replace damaged irreplaceable organs

Question 11

What are the 1st and 2nd gen. of biologics?

Answer 11

1st gen- COPIES of endogenous proteins produced by recombinant DNA tech
2nd gen- ENGINEERED proteins to improve performance

Question 12

Do all drugs target proteins?

Answer 12

NO
Some target macromolecules like DNA (cisplatin)

Question 13

Are all drugs 100% specific?

Answer 13

NO

Question 14

Does increasing the dose increase the specificity?

Answer 14

NO
Also leads to unwanted side effects/ toxicity

Question 15

What is an allosteric antagonist and give an example?

Answer 15

Flumazenil (used for overdoses of benzodiazepines)
When bound to the allosteric site it reduces the affinity of the orthosteric site to the ligand

Question 16

Name 4 cellular responses that happens when an agonist is bound to a receptor

Answer 16

1. Ion channel open
2. Enzyme activation or inactivation
3. Ion channel modulation
4. DNA transcription

Question 17

What is an inverse agonist? Difference between this and an antagonist?

Answer 17

Opposite effect of agonist at the same receptor (THERE IS A RESPONSE)
Antagonist has NO RESPONSE (efficacy = 0)

Question 18

Basic mechanism of ionotropic receptor

Answer 18

Ion channel
Channel opened by agonist
Ions flow through changing membrane potential

Question 19

Basic mechanism of metabotropic receptor

Answer 19

1. rest state alpha and beta-gamma subunits attracted to eachother
   GDP associated to alpha
2. Agonist bound
   changes confirmation of proteins, beta-gamma separates from alpha as less attracted because alpha bound to GTP (exchange reaction)
3. Down stream effectors (adenylyl cyclase for Gs protein)
4. alpha = nucleokinase (GTP -> GDP + Pi)
   Alpha now extremely attracted to beta-gamma