1a Pharmacology and Neurotransmitters Flashcards
What is the definition of pharmacology?
The study of how chemical agents can influence the function of living systems
a chemical substance that interacts with a specific target within a biological system to produce a physiologic effect
why do people take heroin?
euphoria
analgesia (pain relief)
cough suppression
which parts of the brain produce the following responses:
analgesia, euphoria, cough suppression
analgesia: peri-aqueductal grey region
euphoria: ventral tegmental area
cough suppression: cough nucleus
what 3 qs must you know the answer to when making new drugs?
where is the effect produced?
what is the drug target?
what is the response produced after interraction with this target?
What are the four most common drug targets?
Receptors, Enzymes, Transport Proteins and Ion channels
What must a successful drug show?
high levels of specificity for a particular target - this is to prevent the drug binding to different things and causing undesired effects
What is an adverse affect?
A side effect which has negative health consequences
What can cause side effects?
When the drug results in off-target effect, or the drug acts on different targets on the same tissue
What is the “safest drug”
Where there is the largest difference between the dose required to induce the desired effect and the dose required to induce side/adverse effects
Why is selectivity more important for drugs than endogenous products of the body?
Endogenous products are produced specifically where they act, where as drugs have to travel in the blood stream to reach their target - more chance of the drug binding to the wrong thing and causing adverse effects
describe briefly transmission across a few neurones
- transmitter released from 1st cell
- synaptic activation of 2nd cell
- signal integration and signal conduction by 2nd cell
- signal transmitted to effectors/subsequent neurones
what 4 things explain why we need synaptic transmission
rapid timescale, diversity, plasticity, learning and memory
What is the size range of the synaptic cleft?
20-100nm
what comes before and after a synapse?
pre-synaptic nerve ending/terminal button
gap 20-100nm
postsynaptic region (dendrite or cell soma)
What type of transmission if an action potential?
Electrical transmission
What type of transmission is synaptic transmission?
Chemical transmission
what are the 3 basic stages of synaptic transmission?
- biosynthesis, packaging and release of neurotransmitter
- receptor activation
- inactivation
What ion is essential for NT release?
Ca2+ - bind to vesicles which allows them to fuse with pre-synaptic membrane and release NT via exocytosis into synaptic cleft
transmitter release requires aan increase in intracellulr C2+ (200 um)
What are some amino acid NT’s?
Glutamate, GABA and glycine
What are some amine neurotransmitters?
Noradrenaline and dopamine
what are some neuropeptides transmitters?
opioid peptides
describe briefly neurotransmitter release
- membrane depolarisation
- Ca2+ channels open
- C2+ influx
- vesicle fusion
- vesicle exocytosis
- transmitter release
Describe the stages of NT release?
- Action potential arrives at pre-synaptic bouton
- AP results in the opening of Ca2+ ion channels
- This results in a large influx of Ca2+ ions into the neurone
- The Ca2+ ions bind to the NT vesicles and cause the vesicles to fuse with the pre-synaptic membrane
- This releases the NT into the synaptic cleft via exocytosis
- The NT then makes contact with the receptor allowing for the depolarisation of the other neurone due to Na+ influx
- The NT is then enzymatically degraded or taken back up into the pre-synaptic bouton
where are synaptic vesicles filled with neurotransmitter docled?
in the synaptic zone