Pharmacology Flashcards
Chemical signals released from one cell only produce a response in the cells which…?
Express the right receptor.
If a signalling molecule is lipid soluble, what does this allow them to do?
Diffuse through the lipid layer of the cell membrane.
Where are the receptors that signalling molecules bind to?
In the nucleus or in the cytosol.
What does nitric oxide bind to?
Soluble guanylyl cyclase in the cytosol
What is the response when nitric oxide binds to guanylyl cyclase?
Generates cGMP as 2nd messenger that regulates cell activity
The receptors for steroid hormones are also often…?
Transcription factors
Where do hydrophilic signalling molecules bind to?
Receptors on the surface of a molecule
Which type of surface receptor interacts with the cytoskeleton?
Integrin receptors
Which kind of surface receptors do all their work via a middle man- the g-protien?
G protein-coupled receptors (GPCRs)
Which type of surface receptors are bound to enzymes?
Receptor-enzymes
Which type of surface receptors have intrinsic enzyme activity?
Rceptor-enzymes
What is the biggest class of cell surface receptors?
G protein-coupled receptors
What happens if the G protein-coupled receptor directs to ion channels?
Affects membrane potential and firing of action potentials
Describe what would happen if a G-coupled receptor coupled to adenylyl cyclase?
Produces cAMP as 2nd messenger
Regulates protein kinase A activity
Phosphorylates target proteins and changes their activity
Describe what would happen if a G-coupled receptor coupled to phospholipase C?
-Produces IP3 and DAG as 2nd messengers
-Releases Ca2+ and regulates protein kinase C activity
-Phosphorylates target proteins and changes their activity
Name some sources of calcium so it can be used as a second messenger.
From internal stores via IP3-
Via inhibition of Ca2+ transport out of the cell
From outside the cell via voltage-gated or ligand-gated Ca2+ channels
How is intracellular communication achieved?
Chemical signalling molecules acting on specific receptors
Which type of mechanism ensures receptor activation triggers the appropriate response?
A range of signal transduction mechanims.
Which type of mechanism ensures receptor activation triggers the appropriate response?
A range of signal transduction mechanism.
What is a drug?
Any chemical agent that affects a biological system
What is affinity determined by?
Strength of chemical attraction between drug and receptor
What does a low EC50 indicate?
High affinity
What is efficacy determined by?
How well the drug is at activating the receptor
What do agonists do?
Agonists mimic normal effect of receptor
What do antagonists do?
Antagonists block normal action of receptor
What is the affinity of a full agonist?
High affinity
What is the efficacy of a full agonist?
High efficacy
What is the affinity of a partial agonist?
High affinity
What is the efficacy of a partial agonist?
Medium efficacy
What is the affinity of an antagonist?
High afficacy
What is the efficacy of an antagonist?
No efficacy
Define selective agonists.
Drugs that activate some receptor
Define selective antagonists.
Drugs that block only some receptors.
