Pharmacology Receptors (L3&4) Flashcards
(19 cards)
What is a metabotropic receptor?
A receptor which acts through a secondary messenger
Describe the structure of GCPR and associated G-proteins
Single polypeptide, 7 transmembrane domains (alpha helices), ligand bind to either extracellular domain or transmembrane,
Give examples of G-protein coupled receptors
Muscarinic acetylcholine receptor, Alpha/Beta receptors
Give an example of enzyme-linked receptor
alpha/beta receptors
Describe a model of G-protein recycling and activation of second messenger systems
When a ligand binds to the GCPR it causes conformational change and causes alpha subunit to exchange GDP-GTP activating alpha unit and carries out effect, beta-gamma subunit which also carries out effects, alpha subunit then hydrolysed producing GDP which rebinds to GCPR
What is mean by structure activity relationship?
Where the structure of a ligand affects the amount of activity
Give an example of enzyme-linked receptor
Insulin receptor
What is a common path of activation of molecules?
Phosphorylation
What do alpa and beta adrenorecpetors cause?
Alpha- constrict blood vessels and bronchioles
Beta- increases HR and bronchodilation
How does an enzyme linked receptor work?
Tyrosine kinase domain, receptor binds, causing two receptors together and phosphorylate each other, which causes cellular response
What is an ionotropic receptor?
Receptors links to ion channels (ligand-gated ion channels)
What are examples of ionotropic receptors?
Nicotinic
GABA
What is the difference between reversible and irreversible antagonists
Reversible will unbind and an irreversible will not
What is an example of a reversible and irreversible antagonist?
Irreversible-
alpha- bungarotoxin
Reversible-
delta- tubocurarine
Outline the structure of a nicotinic receptor
5 subunits, 2 alpha, beta and gamma, 1 either delta or epsalon
Each subunit has 4 transmembrane domains
What is the difference between an inverse agonist and antagonist?
Inverse agonist does the opposite to the agonist
Agonist- opens receptor
Antagonist- stops agonist
Inverse agonist- closes receptor no matter what
What is an allosteric modulator?
Modulators that bind to a GABA receptor but act in different site to agonist
How do intracellular receptors work?
Hormones cross plasma membrane to bind to cytoplasmic receptors, changes shape and removes inhibitor, hormone receptor complex binds to DNA and affects transcription effecting change in gene expression
What are the different parts to an intracellular receptor?
Ligand binding domain, DNA binding domain, transcription activating domain
