Mechanisms of Drugs action Flashcards
What are the molecular mechanisms of drug action (4 main ones and a bonus)
1) Direct physicochemical effect
2) Transport systems
3) Enzymes
4) Interaction with the 4 major types of receptors (Cell signalling Part II)
AND) Others: adhesion molecules, organelles and structural proteins
What is pharmacodynamics and by what are the 4 main concept to consider?
‘What the drug does to the body’
1) Modes of action
2) Interaction with receptors and signaling pathways
3) Dose response relationships
4) Biochemical and physiological effects of drugs
What is a direct Physicochemical Effect? (3 examples given)
A direct impact - not depending on receptors or pathways to bind to and produce an effect downstream…
e.g.
Bulk forming laxatives
Antacids
Osmotic diuretics
How can a drug have an effect on Transport Systems?
Alter a trasport system, e.g. proteins that have a transport job are modulated by the drug and so their normal physiological role is disrupted (up or down regulated)
Ion Channels
Voltage (and Ligand-gated) ion channels
Second-messenger-regulated – a second messenger regulated by a G-coupled protein receptor
Cell membrane ion pumps
Active transport of ions against their concentration gradients
Proton pump inhibitors (e.g., omeprazole) - K+/H+-ATPase in gastric parietal cells
Digoxin - Na+/K+-ATPase (cardiac tissue)
Transporter
Symport, Antiport
Thiazide diuretics - Block Na+/Cl−co-transport in the renal tubule (symport)
How could a drug act using an enzyme as a target?
Intracellular or extracellular enzymes involved in synthesis or degradation of subtracts
A drug can inhibit the enzyme by
Binding to the active site – enzyme not able to bind to substrate
Binding to another site in the enzyme, changing its conformation – enzyme not able to bind to substrate
(Drugs might be able to activate enzyme / increase its genetic transcription)
Major types of drug receptors - what are they? (4)
names
mechanism
speeds
examples of each one
