W3- Lecture 13.1- Receptors (pharma)

Question 1

What is a receptor ?

Answer 1

A transducer (coverts an extracellular Signal to an intracellular one )

Question 2

How do drugs take action in the body ?

Answer 2

By acting on receptors

Question 3

Name three types of ion channels

Answer 3

Voltage gates
Ion pumps/transporters
Ligand gated (ionotropic)

Question 4

Name 1 type of voltage gated channel

• important for?
• site of action for ?
• structure

Answer 4

Voltage-gated sodium channel

• important for action potential
• site of action for local anaesthetics e.g lidocaine which is a sodium channel blocker
• subunits form channel with central pore

Question 5

Name 4 types of receptors

+time scale

Answer 5

Ligand gates ion channels- milliseconds
G-protein coupled receptors (metabotropic)- seconds
Kinase linked receptors- hours
Nuclear receptors- hours

Question 6

Name a ligand-gates ion channel antagonist

On what receptor ?
Action

Answer 6

ondansetron (Zofil)
Acts on 5HT3
Anti-emetic (reduces vomiting )

Question 7

Explain a nicotinic acetylcholine receptor :
Structure 
activation 
Structural change 
Speed 
Effect

Answer 7

Structure- 5 protein sub units, each subunit has 4 trans membrane domains.
TM2 from each subunit lines the ion channel pore

Activation - acetylcholine or ligand binds(to alpha subunits)
Change - pore opens and allows sodium through (down conc grad)
Speed = fast

Effect- depolarisation of cell (muscle contraction /action potential )

Question 8

Name a 5HT3 blocker

+ use

Answer 8

Ondansetron

Anti-emetic aka anti vomiting

Question 9

use of GABA(A) ligands for ligand gated ion channels

Answer 9

Anti anxiety

Sleep disorders

Question 10

Where does strychnine act ?

Effect

Answer 10

Blocks glycine receptors

Poison

Question 11

What happens is an ionotropic glutamate receptor is over activated?
What drugs are used to treat

Answer 11

Caused neurodegenration

None currently effective drugs