Lecture 17 - What is a receptor? Types and function Flashcards
Name the four main proteins which drugs target
receptors
ion channels
enzymes
transporters
Where are ion channels found?
on membranes
When do ion channels open?
in response to an environmental cue, such as depolarisation of the membrane
What is the role of ion channels?
To allow the passage of channel-specific ions down the concentration gradient
Name and describe two categories of drug which act on ion channels
- blockers = prevent ion movement through the ion channel
- modulators = increase/decrease the chance of the channel opening
Give an example of a drug which is a blocker that acts on ion channels
lidocaine - blocks voltage gated sodium ion channels
Give an example of a drug which is a modulator that acts on ion channels
Gabapentin - reduces the activity of voltage-gated calcium channels
What is an enzyme/ what is their role?
To act as biological catalysts and speed up chemical reactions
they mediate biochemical signals within cells and tissues
Name the three categories of drugs which act on enzymes
inhibitors
false substrate
prodrug
Effect of inhibitor on enzyme
give an example
prevent activity
aspirin- a cyclooxygenase inhibitor
Effect of false substrate on enzyme.
Give an example of a drug
abnormal metabolite is produced
fluorouracil used for chemotherapy
Effect of prodrug on enzymes.
give example of a drug.
activation of drug molecules - for example codeine is converted into morphine by the enzyme.
What is the role of transporter proteins?
transport/carry substances across membranes against the concentration gradient by active transport.
Difference between channel and transporter proteins.
channel protein open at both sides of membrane at once. Transporters do not.
The two types of drugs which act on transporter/carrier proteins are…?
inhibitor and false substrate
Describe the effect of inhibitor drugs on transporters. Give an example
inhibitors block transport. For example, fluoxetine is a serotonin transport blocker
Describe the effect of false substrate on transport proteins. Give example.
abnormal compound accumulates
For example, amphetamine acts on dopamine and noradrenaline transporters.
Where are receptors found?
cell membranes
What is a receptor?
proteins found on the surface of cell which receive and transduce signals
How do receptors work?
Something binds to receptor and the receptor responds to this exogenous cue and relays a signal into a cell to produce a response
Name three types of drugs which act on receptors
agonist, antagonist and modulator
What is an agonist drug and give an example.
A drug which binds to receptor (a ligand) which induces a response.
For example, morphine activates opioid receptors.
What are antagonist drugs? Give an example.
Antagonist bind to receptors (ligand) and block the receptor, preventing activators from binding to it.
Example: naloxone blocks opioid receptors
ligand
something that binds