Lecture 2.1: Structure & Classification of Receptors Flashcards
Why is cell signalling important?
It permits effective communication and regulation of cells and cellular processes
What are the steps in cell signalling?
Reception
Transduction
Response
Amplification
Receptors are proteinaceous, what does this mean?
Capable of selectively binding a ligand (therefore, responses are selective as well)
Receptor numbers are not static, what does this mean?
- Increased numbers of receptors =
upregulation (increased sensitivity) - Decreased numbers = downregulation
(desensitisation or tachyphylaxis) - Desensitisation occurs after a series of doses,
tachyphylaxis may occur after the first dose
What is a Ligand?
A molecule that binds to a receptor
Examples of Ligands
- Hormones
- Neurotransmitters
- Growth Factors
- Drugs
What is a ligand which binds and activates called?
Agonist
What is Agonist Potency?
[Agonist] needed to produce 50% maximal response
What is Agonist Efficacy?
Ability of an agonist, after binding, to activate receptors
What is a ligand which binds and blocks agonist binding called?
Antagonist
What is a which fails to produce maximal response on binding called?
Partial Agonist
What type of receptor is a Ligand gated ion channels?
Ionotropic Receptors
What type of receptor is a G protein-coupled receptors (GPCR)?
Metabotropic receptors
What type of receptor is an Enzyme-linked receptors?
Kinase-linked receptors
What type of receptor is an Intracellular receptors?
DNA-linked nuclear receptors