Drug Receptor Classes. Flashcards
What is pharmacodynamics?
How the properties of drugs influences their interactions with the body.
What are the 4 main types of target for drugs?
Receptors.
Enzymes.
Ion channels.
Transporters.
What happens when a drug binds to a receptor protein?
There will be an intracellular response e.g. a channel opens.
Where in the body are most receptor proteins found?
In cell membranes.
What happens when drugs bind to enzymes?
They can either induce them or inhibit them.
Will most drugs inhibit or induce enzymes?
Inhibit them.
What effect will drugs have on ion channels?
They will either inhibit or open the ion channels e.g. anaesthetics block sodium channels.
What is the mode of action of drugs that act as ion channel modulators?
They increase or decrease the probability that an ion channel will open.
What is the mode of action of drugs that bind to transporter proteins?
They can either inhibit or enhance the transport of the compound that the transporter is supposed to transport.
What kind of ion channels will only open or close when there is a change in membrane potential?
Voltage gated ion channels.
What is the refractory period for voltage gated ion channels?
The period where the ion channel cannot be influenced (opened).
How do drugs affect the refractory period of voltage gated ion channels?
Most drugs will increase the refractory period of these channels.
What are 4 types of drugs that activate voltage gated ion channels?
Local anaesthetics.
Antu epileptics.
Anti dysrhythmics.
Drugs that affect the release of neurotransmitters.
How are ligand gated ion channels activated?
They open when a particular molecule binds to a receptor on these channels.
How do drugs get ligand gated ion channels to open?
A drug can be made to resemble the ligand and this will cause the channel to open.
How do drugs affect ligand gated ion channels.
They increase the opening frequency of these channels or modify the time that these channels are open for.
What happens when an ion channel opens?
Ions rush into or out of the cell and this changes the membrane potential and leads to a response.
What are 3 examples of ligand gated ion channels?
Nicotinic receptors.
GABA receptors.
Glutamate receptors.
What receptors are coupled to a G protein?
GPCR receptors.
What happens when a drug binds to a GCPR receptor?
The Gi, Go or GQ protein will be activated.
What are the 4 classes of G protein that are found in GCPRs?
Gi proteins.
G0 proteins.
GQ proteins.
GS proteins.
What determines the intracellular responses following the activation of a GCPR?
The type of G protein that is activated.
What is the role of Gi/G0 G proteins following activation of a GCPR?
They inhibit the enzyme adenylate cyclase and this causes a decrease of cAMP in the cell.
What happens in a GCPR once adenylate cyclase has been inhibited by the Gi/G0 protein?
There is an increased outflow of potassium ions and an increased influx of calcium ions.
This changes membrane potential.
What are 3 examples of a GI/G0 GCPR?
Muscarinic M2 receptors.
Alpha-2 adrenoceptors.
Serotonin receptors.
What happens when GQ GCPRs are activated?
The GQ proteins activates phospholipase C which leads to an increase in insP3 and calcium ions within the cell.
What happens in GQ GCPRs after the GQ protein has lead to an increase of insP3 and calcium ions within the cell?
It leads to the conversion of PIP-2 to DAG and this results in an increase in protein kinase C.
What are 4 examples of GQ GCPRs?
Alpha-1 adrenoceptors.
Muscarinic M1 and M3 receptors.
Serotonin receptors.
Histamine H1 receptors.
What happens when a GS GCPCR is activated?
The GS protein activates adenylate cyclase and this leads to an intracellular increase of cAMP.
What determines how long the drug takes to have an effect?
The type of receptors that are used by drugs.
What are examples of GS GCPR receptors?
Beta adrenoceptors.
Serotonin receptors.
Dopamine receptors.
Histamine H2 receptors.
When are kinase linked receptors activated?
When a particular ligand binds to the receptor.
What happens in a kinase linked receptor once it has been activated by a ligand?
There will be protein phosphorylation and this leads to gene transcription.
What can be made following gene transcription?
Proteins.
Will drugs that affect kinase linked receptors have very quick effects?
There is a long time between administration of these drugs and any visible effects.
Where are nuclear receptors located?
In the nucleus.
What must drugs that travel to nuclear receptors be able to do?
Enter the cell and bind to DNA within the nucleus.
What are 2 common drugs that bind to nuclear receptors?
Glucocorticoids/corticosteroids.
What effects can drugs that bind to nuclear receptors have?
Gene activation and gene repression
