Receptors Flashcards
(30 cards)
How many molecules of ACh bind to nAChRs? [1 mark[
2
Definition of potency [1 mark]
How much agonists are needed to produce an effect
Equivalent to potency [1 mark]
Threshold concetration
Definition of efficacy [1 mark]
Ability of an agonist to induce a biological effect
Definition of antagonists [1 mark]
Drugs that bind receptors without activating them
Structure of ligand gated ion channels [2 marks]
- Pentamer
- Each protein has 4 transmembrane domains (hydrophobic)
How many antagonist binding sites are there in ligand gated ion channels? [1 mark]
2
What is the neuromuscular junction? [1 mark]
The synapse between a motor neurone and a skeletal muscle fibre
Muscle type nAChRs in proteins (in adults) [5 marks]
- α1
- ε
- α1
- β1
- δ
What do foetal muscle type nAChRs have instead? [2 marks]
γ nAChR instead of ε nAChR
What does the body create antibodies for in Myaesthenia Gravia? [1 mark]
α1 subunit
Clinical sign of Myaesthenia Gravia [1 mark]
No miniature end-plate potentials (mepps)
Symptoms of Myaesthenia Gravia [5 marks]
- Muscle weakness
- Drooping eyelids
- Fatigue
- Difficulty swallowing or talking
- Difficulty in exertion
Structure of G protein coupled receptors? [2 marks]
- 1 protein (exception: insulin receptor)
- 7 transmembrane domains
Which G protein subunit does GDP bind to? [1 mark]
Alpha
What does alpha Gs do? [2 marks]
- Activates adenylyl cyclase
- Increases [cAMP]
What does alpha Gi do? [2 marks]
- Inhibits adenylyl cyclase
- Decreases [cAMP]
What does alpha Gq do? [2 marks]
- Activates PLC
- Increase [Ca2+]
What does the alpha subunit in the G protein have? [1 mark]
GTPase
What happens to the affinity of alpha subunit to an enzyme that modulates a secondary messenger cascade when GTP is hydrolysed? [1 mark]
Affinity decreases
What is the excitatory junction potential caused by? [1 mark]
The influx of Na+ and Ca2+ ions
What is made from the hydrolysis of PIP2 by PLC? [2 marks]
- Diacylglycerol (DAG) = interacts with lots of enzymes
- Inositol triphosphate (IP3) = releases Ca2+
What recognises phosphotyrosines?
SH2 domains of other proteins
What pathways are activated by the activation of tyrosine kinase receptors? [2 mark]
- Ras
- PIP2
