Introduction to Pharmacology Flashcards
What is a ligand?
Refers to any molecule that binds to the receptor
What is a receptor?
Protein that binds chemical mediators
What are the four classes of drug receptors?
- Ion channels
- Enzymes
- Carriers/Transporters
- Receptors
Give 3 examples of drugs that bind to ion channels
Lignocaine
Apamin
Dihydropyridines e.g. nifedipine
Lignocaine mechanism
- Binds to Na+ channels (responsible for firing of APs)
- Stops it from firing action potentials when bound
- -> decreases sensation of pain
Apamin mechanism
- Binds to SK channels (involved in hyper polarisation)
- Rapid firing of action potentials when bound
- -> increased sensation of pain
What are SK channels?
Small conductance calcium-activated potassium channels
Nifedipine mechanism
- Binds to Ca2+ channels in smooth muscle cells and cardiac muscle
- Inhibition by blocking Ca2+ entry –> muscle becomes relaxed –> decreases bp
Give examples of 3 drugs that target enzymes
- Acetylsalicylic acid
- Pargyline and clorgyline
- Captopril
Acetylsalicylic acid mechanism
Binds to cyclooxyrgenase (COX)
COX produces lipid mediators –> promotes inflammation, pain, fever
Pargyline and clorgyline mechanism
Binds to monoamine oxidase (MAO)
Stops breakdown of neurotransmitters –> increases [neurotransmitters] so they act longer
Used to treat depression
What is captopril an example of?
A drug that targets enzymes
ACE inhibitor
Give 2 examples of drugs that target transporters
- Fluoxetine
- Digoxin
Fluoxetine mechanism
Works on transporter in the brain
- Transporter responsible for the uptake of serotonin and terminates its action
- Fluoxetine inhibits the transporter so levels of serotonin remain elevated
Should you use fluoxetine or MAO inhibitors?
Fluoxetine is more specific in its action and has less side effects than MAO inhibitors
