pharmacology of the nervous system Flashcards
what does pharmacology mean
a chemical substance that interacts with a specific target within a biological system to produce a physiological effect
what are the 2 types of side effects
1) side effects that are due to effects on the same target
2) side effects that can be produced by drug action on :
- other targets in the same tissue or other tissues
- on the same target in other tissues
what is a feature of the safest drugs
a large difference between the dose required to induce the desired effect and the dose required to induce side/adverse effects
what are the 4 main classes of drug targets
- receptors
- enzymes
- transport proteins
- ion channels
what is the target for Atorvastatin
enzyme
inhibits HMG coA reductase
what is the target for amlodipine
ion channel (blocks ion - calcium channel > vasodilation > decreases blood pressure)
what is the target for salbutamol
receptor
activates beta 2 receptor within lung - bronchodilator
what is the target for citalopram
transport protein
block serotonin reuptake protein to produce antidepressant effect
what 2 things can drugs do
act on targets to ENHANCE activation (stimulate an effect)
or PREVENT activation (block an effect from being produced)
what does a drug need to show to be an effective therapeutic agent
a high degree of selectivity for a particular drug target
lock and key hypothesis
eg using NTs dopamine, NA and serotonin are structurally similar - may fit into similar locks - might expect them to bind to the same target
is selectivity for drugs more important than endogenous compounds (made inside cells)
yes - drugs can be taken through the oral route and need to get into body bloodstream to be distributed to relevant tissue (can be distributed to any tissue by bloodstream)
whereas endogenous compounds eg NTs are specifically delivered to drug target > release NT into synpase where it acts on receptors on other nerve
what is the definition of side effects
an effect produced by the drug that is secondary to the intended effect > if the side effect has negative health consequences = adverse side effect
what is the definition of an agonist
a substance which initiates a physiological response when combined with a receptor
what is the definition of an antagonist
a substance which interferes with or inhibits the physiological action of another
key features of dosage
low dose and slowly increase till therapeutic effect is reached
increasing the dose more - side effects (as it can fit into more similarly structured receptors)
keep dose relatively located to therapeutic effect
increasing the dose > decreases selectivity > unwanted side effects
