2.4: Pharmacology of the nervous system Flashcards
Define pharmacology
A chemical substance that interacts with a specific target within a biological system to produce a physiological effect
3 questions when considering pharmacology of a drug?
Drug target?
Where effect produced?
What response is produced?
How can you determine drug safety based on dosage?
Safest drugs have a large difference between doses required to present the desired effect vs dose leading to side effects
4 drug targets (proteins)
Receptors
Enzymes
Transport proteins
Ion channels
What protein does Atorvastatin act on?
Enzyme - HMG CoA reductase
What protein does Citalopram act on
Transport protein - serotonin re-uptake protein
What class of protein does Salbutamol act on?
Receptor - Beta-2 adrenergic receptor in lung
Activates it’s target
What class of protein does Amlodipine act on?
Ion channel - Ca2+ channel
Why might selectivity be more important for drugs than endogenous compounds (e.g. dopamine)
Neurotransmitters are very specifically delivered to their drug target (released by some post synaptic neurones to react directly with their receptors)
Drugs would need to pass through the blood to reach a certain tissue, however it could enter any tissue and so does not directly interact with target
What is the definition of a side effect
Effect produced by a drug that is secondary to intended effect
What is meant by an adverse effect
If a side effect has negative health consequences
Name for a drug that tries to mimic the effects of dopamine by binding to a dopamine receptor?
Dopamine receptor agonist
As drug dosage increases, what happens to the selectivity
Decreases
- drug more effective
What is meant by on-target effect of a drug
Utilises same target, but effect in different tissue which isn’t necessarily wanted
What effect increases as dosage of a drug increases?
Off-target effects
2 effects drugs can have on targets
Enhance activation (stimulate effect)
Prevent activation (block an effect)
What makes an effective therapeutic agent
High selectivity for particular drug target
Why do side effects occur
Drugs have off target effects
e.g Pramipexole selectivity
2 reasons why side effects occur
-Drug action on other targets in same tissue / other tissues
-On same target in other tissues
What makes a drug safe
large difference between dose required to induce desired effect and dose required to induce side effects
