Receptor Mechanisms 1 Flashcards
What are 4 supergroups of receptors?
G protein coupled receptors
Tyrosine kinase linked
Ligand hates ion channel
Nuclear/steroid
Which group of receptor produce super fast receptor responses?
Ligand gated ion channels
What does ligand gated ion channel receptor family consist of?
Nicotinic cholinreceptor
5HT3
GABAa
Glycine
What agonist is stimulated by nicotinic cholinoceptor?
Acetylcholine
What agonist is stimulated by 5HT3?
5-HT
What agonist is stimulated by GABAa?
GABA
What agonist is stimulated by glycine?
Glycine
What ion stimulates nicotinic +5HT3 receptors?
Ion Na/Ca
Depolarise
More excitable
What ion stimulates GABAa + glycine receptors?
Ion Cl
Hyperpolarises so don’t allow cations into cell, allows anions into cell
Describe the structure of ligand gated ion channel receptor?
Ligand binding site
Ability for ions to move to create aqueous channel
Consists of 5 similar proteins
Each protein has 4 transmembrane domains which forms ligand gated ion channel
In functional LGICR, there is total of 20 transmembrane domains
2nd transmembrane protein creates ionic pathway
Receptor activation allow ions to flow
How?
Agonist binds to receptor, you get a molecular kink. The ion pathway is open so ions can flow into cell. Response is milliseconds
2 molecules of agonists are required to get full opening of ion channels
There are 2 agonist binding site in this receptor
What nicotine type acetylcholine receptors are found in skeletal muscle?
N1/NM
What nicotine type acetylcholine receptor is found in CNS + autonomic ganglia?
N2/NN
What is neuromuscular junction?
Short distance between neurone + muscle
Is where Ach is released
What is the disease called in which receptors have failed?
What happens?
Mynasthesia gravis
Muscle nicotinic AchRs become degraded
Autoimmune disease
Targets a1 subunit
Neuronal nicotinic AchRs unaffected => a2, a8 + B2-B4
Muscle weakness, drooping eyelids, fatigue, difficulty swallowing or talking + exertion is difficult
