Pharmacodynamics Flashcards
Name the 4 mechanisms
Receptors
Ion channels
Carrier molecules
Enzymes
What is a protein?
A protein is made up of amino acids which form long chains
What is an ion?
An ion is a molecule with an electrical charge, can be positive or negative charge
What is tachyphylaxis?
A rapid desensitisation to a substrate caused by cellular change and metabolic degradation, change or loss of receptors
What are the 4 main types of receptors?
Ion channels
G-coupled protein
Nuclear
Kinase
Explain ionotropic (4)
Ligand gated
Nicatinic ACh receptor
Works on excitable tissue
Works in milliseconds
Explain metabotropic (6)
G-coupled proteins
2nd messengers
7 TMD
Amplifies signals
Drugs usually lipophilic
Can be complex
What is kinase-linked? (3)
Drugs take longer to work
Insulin/growth hormones
2 important pathways
-cell division and growth
-inflammation
What is a nuclear receptor? (6)
Can switch genes on and off
Powerful receptor
Ligands have to enter cell to bind
Effects have slow onset
Intracellular protein
Eg, steroids
Explain ion channels (6)
Important if rapid response required
Drugs block or modulate channels
Can be open, closed or inactive
Made up of proteins
Have 4 main channels
Examples, benzos and anesthetics
What are the 4 ion channels?
Ligand gated
Volted gated
Mechanically gated
Intra or extracellular gated
What is a carrier protein? (5)
Protein that helps substrate across the cell membrane
Shape specific
Can be targeted and blocked
Have 3 types
Examples, glucose, ions and amino acids
What are the 3 types of carrier protein?
Transporter- single molecule
Symporter - 2 same direction
Antiporter - 2 opposite direction
What are enzymes?
Enzymes speed up reactions
Act on specific sustrates
Contribute to a large number of drug reactions
What is an enzyme? (4)
Speeds up reaction
Act on specific substrates
Part of a lg number of drug reactions
Can incluse analoge, false or conversion of pro drugs
What is an analogue substrate? (3)
Similar shape
Competitive inhibition
Reversible and irreversible
What is a false substrate? (3)
Similar shape
Produces abnormal product
Disrupts normal pathway
What is a conversion of a pro drug? (5)
Given in inactive form
Relies on conversion of enzymes
Competitive inhibitor
Slows down reaction
Example, codeine
What is ionisation? (5)
Ionised and unionised forms of weak acids and bases
Disassociation constant measures this pka
Acid to alkaline and vice versa
Water solutions attract ionised
Lipid solutions attract nonionised
Explain drug half life (2)
Time taken for the concentration of a drug to fall by half in the bloodstream
Excretion and metabolism determine a drugs half life
Explain steady state
Steady state is when the concentration levels of a substance in the blood equals that of elimination
what does pKa mean?
The pKa is a measure of the relative strength (degree of ionization) of a weak acid or base
What is an agonist?
A drug or substance that binds to a receptor and causes the same action as the substance that normally binds to the receptor
What is an antagonist?
a substance that stops the action or effect of another substance.
