2.1 Explain the molecular basis of the action of medicines Flashcards
What are the 3 Drug-receptor interactions?
Agonists: full and partial
Antagonists: competitive or irreversible
Specificity: ability to combine with one particular receptor
What are the possible ways in which medicines work?
For each way name the specific examples used in the drugs you are personally studying.
Action on hormones (e.g. Thyroxine)
Action on transmitter substances (e.g. adrenaline)
Action on membrane transport systems (e.g. Proton pumps)
Action on enzymes (inactivation of potassium ATPase)*
Defintion of Agonist?
A substance which initiates a physiological response when combined with a receptor (normally correcting something that has been lost).
Name the 2 types of agonists and their definitions
Full agonist:
Full agonists bind to and activate a receptor, producing the maximum possible response that the tissue being targeted is capable of giving.
Partial Agonist:
partial agonists are drugs that bind to and activate a given receptor, but have only partially produce the desired effect.
For each drug name their drug-receptor interaction
Amoxicillin: Causative agent
Levothyroxine: Full Agonist
Omeprazole: Irreversible Antagonist
Beta blockers: Competitive Antagonist
Define the differences between the 3 types of antagonists and what an antagonist is?
Antagonist: Slow or stop a process by ‘getting in the way’ of something in that process
Competitive antagonists slow down a process by temporarily blocking a site/ receptor.
Irreversible (non-competitive) antagonists stop a reaction permanently blocking a site/ receptor
State the 7 Stages of Synapse and its functioning (Beta blockers)?
- Action potential (Wave of excitation)
- This wave stimulates the opening of calcium channels thus Ca2+ floods into the presynaptic membrane.
- As a result of the Ca2+ the vesicles containing neurotransmitters migrate towards the postsynaptic membrane.
- Neurotransmitters released into the synaptic cleft due to exocytosis.
- Neurotransmitters diffuse across cleft and bind to receptors (In this case Beta receptors).
- Beta receptors open Na+ channels therefore Na+ floods through the postsynaptic membrane.
- When Na+ reaches a specific level/concentration a new action potential is generated.
What is the Molecular basis of the action of Beta blockers?
- They temporarily block the receptor sites (beta adrenoceptors) for adrenaline and noradrenaline (hormonal neurotransmitters found in the sympathetic nervous system) they slow down, but do not stop, the impulse to the heart.
- So, they slow down the heart rate and the force of heart muscle contraction is reduced; thus reducing blood pressure.
What are Beta blockers used to treat?
Useful for treating high blood pressure, angina, atrial fibrillation, people with heart failure and reducing the chance of heart attack.
What is Amoxicillin used to treat?
Used to treat Bacterial infections, such as chest infections (including pneumonia). It can also be used together with other antibiotic medications to tackle stomach ulcers.
What is the Molecular basis of the action of Amoxicillin?
Amoxicillin binds to the section which would form the crosslinks stopping (inhibiting) it from happening. This means the cell wall cannot grow / fill in any holes.
What is the normal cycle of a bacteria cell wall synthesising?
A cell wall of a bacteria cell is made of *Peptidoglycan new peptidoglycans are synthesised inside the cell, moved (exported) through the membrane and then attached (form cross-links) to other peptidoglycans which are already part of the growing wall.
What is Omeprazole used to treat?
Used to treat GERD and stomach ulcers.
What is the Molecular basis of the action of Omeprazole?
Its action at the molecular level involves inhibiting a proton pump, which is found in the parietal cells of the stomach lining.
The proton pumps are located on the luminal side thus it is in contact with the liquid side of the cell.
ATP binds to carrier protein which allows active transport of a proton across the membrane in exchange of potassium.
Omeprazole (PPI) binds irreversibly to the ATP binding site on the proton pump.
In 4 step describe how Omeprazole eventually blocks the final step of acid production, lowering stomach acidity?
- Activation: Omeprazole is inactive in its normal form. When it enters the acidic environment of the stomach, it is converted into its active form.
- Binding: The active form of omeprazole binds to the proton pump enzyme (H+/K+-ATPase) in the stomach lining.
- Inhibition: Once bound, omeprazole inhibits the proton pump, preventing it from pumping hydrogen ions (H+) into the stomach, which are necessary for acid production.
- Result: This reduces the overall secretion of stomach acid, helping treat conditions like acid reflux, ulcers, and GERD.
