Drugs and Receptors Flashcards
What are the benefits to a drug being highly target specific?
Less side-effects. If a drug binds only to a specific receptor there will be no side-effects at all.
What do drugs need to do in order to produce a response?
Bind to particular parts of a cell or tissue. These are called targets.
Name the 6 key targets that drugs bind to…
ERIC FD
Enzymes Receptors Ion Channels Carrier Molecules/Pumps DNA Foreign Proteins
What does a drug activate when it binds to a receptor?
The drug activates the G protein and then influences actions in the cell.
Give 3 examples of drugs that bind to receptors…
Salbutamol
Anti-histamines
Beta Blockers
What happens when a drug binds to an Ion channel?
It opens the channel so that more ions (e.g. potassium) can go in or out of the cell. It affects the excitability of cells.
Name 2 examples of drugs that bind to ion channels…
Local anaesthetic
Benzodiazepine
What happens when a drug binds to a carrier molecule/pump?
It inhibits or excites the pump actively transporting things in and out of the cell (e.g. glucose)
Name 2 examples of drugs that bind to carrier molecules (pumps)…
Cocaine (stimulates the pump)
Omeprazole (blocks acid pump)
What happens when a drug binds to an enzyme?
Enzymes are catalysts that speed up chemical reactions in the cell - so drugs can block these to slow down the action of the cell, or activate them to speed it up
Name 2 examples of drugs that bind to enzymes…
Aspirin
Viagra
What happens when a drug binds to DNA in the cell?
The drug gets into the nucleus to bind to the DNA, altering the makeup of the cell and the amount of proteins produced.
What types of drugs bind to DNA? Give an example of a topical drug.
Steroids e.g. hydrocortisone
Name 5 foreign proteins that drugs may bind to:
BAW FV
Bacteria Viruses Fungus Worms - causing body to expel Aoemeba - stops reproduction
What types of drugs target bacteria?
Explain its limitation and give an example
Antibiotics
e.g. Penicillin
They can only target bacteria with a cell wall.
What is an agonist?
A drug that binds to a receptor causing a response
May often mimic chemicals in the body
What is an antagonist?
A drug that binds to the receptor to stop other chemicals producing a response
How is a reversible antagonist reversed?
The block is reversed by a stronger agonist
What happens when an irreversible antagonist (where the cell is blocked permanently) is given?
The effects will last a lot longer than a reversible agonist - until the body produces a new cell.
After the drug binds to a receptor, what are the 2 stages that happen before there is a response?
Activation of 2nd messenger
Cascade of Enzyme reactions
So - an agonist would activate the G protein (an antagonist would deactivate it).
In a smooth muscle cell this would then activate and increase the 2nd messenger, having lots of effects on other proteins in the cell
What is unique about a nuclear receptor?
The drug must cross the cell membrane to bind to it.
It must be lipid soluble and binds to a receptor in order to cross the membrane to the nucleus, where it binds to the DNA.
Here it switches the gene on or off to produce more/less protein.
What are the 5 possible cellular responses to drugs?
IE CSI
Contraction (muscle cell) Secretion (glands) Excitation (nerve/muscle) Inhibition (nerve cell) Interruption of cell cycle (tumour)
What is drug potency?
The dose of drug needed to produce a certain response.
This can vary between patients - children = less drug needed
High Potency = Small dose
What is the role of second messengers which link drug-binding to cellular responses?
Second messengers such as cAMP, cGMP and calcium are activated when the receptor or G protein is made active or inactive. The activation of the second messenger produces a cascade of reactions in the cell, activating or deactivating different protein productions until the cell responds.
