W8L1 - Intro to Pharma Flashcards
What does the cell membrane do?
What does it mean for neurotrasmitters?
- Acts like a wall
- Preventing things from entering or leaving the neuron.
- Lipid Bilayer
- Fuids and other chemicals like neurotransmitters are not able to pass through
- Require receptors
How many neurons and synapses are there in the brain
- 100 billion neurons in the brain
- 0.15 quadrillion synapses in the cortex
What is the function of a receptor
To allow released neurotransmitters to influence the post-synaptic neuron
Where are receptors located
Located on the outside of the cell membrane
What types of receptors are there
- ) Ion Channels
- ) G-Protein Coupled
How do Ion Channel receptors work?
Are there selective?
- Act as a “gate”.
- NT binds to the receptor outside the neuron
- Gates open
- Ions (both positive and negative) can flow through.
- “Selective”
- Only allow one or a few types of ions to pass through when they are open
- e.g. a calcium ion channel
- Only allow one or a few types of ions to pass through when they are open
What are some properties of receptors (Both ion and G-coupled):
Selectivity, Affected by how many NTs, Specificity
- Selective
- (Lock and Key)
- Only affected by one NT
- (or a drug that mimics NT)
-
Specific in that it will consistently trigger same event
- i.e. either by opening a channel or second messenger)
how do G-protein coupled receptors work?
Work through second messengers (Secondary effect)
- After binding, it activates a “second messenger system” that can either
- (a) open a channel (lol); or
- (b) cause other things to change within the cell
- Cause downstream effects
Define neurotransmitter and neuromodulators,
What are they often distinguished upon
Based on context.
This is a functional description.
NT
- Present in presynaptic terminals
- Released from presynaptic terminals after neuron fires
- Existence of receptors on postsynaptic neurons
NM
- May not be released at pre-synaptic sites
- Often act through second messenger.
What is the difference between neurotransmitter and neuromodulators. Speed and Communication.
Speed and Communications
NT (More specific)
- Either excitatory or inhbiitory
- Rapid (ms), precise, point-to-point communication
- 1 or 2 postsynaptic neurons
NM
- Slower (ms-s)
- Alter subsequent processes of neurons (very general!)
What are examples of excitatory, inhibitory and modulatory NTs
Neurotransmitters/neuromodulators can activate, inhibit or modulate neuronal activity
- Excitatory: Glutamate
- Inhibitory: GABA
__________________________________________________
- Modulatory: DA, NA, ST
How does neuromodulators affect pre and postsnynaptic neurons respectively. How does it affect overall?
Pre: Alter NT release
Post: Alter NT action (alter excitability or firing pattern)
Overall: May cause changes in neural function or structure.
very broad…
One way that neurotransmitters/neuromodulators are able to influence very specific brain functions despite being released all over the brain is due to the fact that
There are different receptors located in specific areas of the brain that are sensitive to one type of neurotransmitter/neuromodulator but can each trigger very different effects.
What is psychopharmocology
Study of drug induced changes in sensation, thinking and behaviour
What are the stages of neurotrasmitters
- Synthesis
- Release from synaptic vesicles
- Binds to receptors
- +/- Influence on post synaptic neuron
- Broken down by enzymes
- Reuptake of transmitter
- Formation & storage in synaptic vesicles
Which stages in NT cycle do drugs affect
Affect all stages
How does drug affect “receptor” stage in NT cycle. Activation vs Blocking what is the name used to describe such drugs
Drugs mimic natural NT or natural neuromodulators
Agonists
- Activate receptors like a natural compound
Antagonists
- Block receptors and prevent natural compound from entering
Compare speed of transmission from nucleus to synapse and synapse to release
Nucleus to Synapse
Relatively slow.
Synapse to Release
Fast. Ready to release. (i.e. fast function)
Define Hormones. Are they Neurotrasmitters?
Signaling molecules produced by glands and transported through the blood to regulate physiology (muscles, neurons etc) and behaviour.
No, because they do not fit the NT description
Explain the bidirectional relationship between pharmocology and psychology?
Pharmacology can affect psychology
- Natural neurotransmitters and artificial drugs can clearly effect mood, cognition & behaviour
Psychology can effect pharmacology
- Emotional or stressful events, thoughts and behaviour effect us BECAUSE they influence our neurotransmitters
Cognitive therapy and pharmacology acts on the same brain
NT and NM (Last Lecture)
NT:
- Directly impacts postsynaptic neuron in Fast Local Signals
NM:
- Modulate function or sensitivity of pre and post synaptic neurons in Slower Global Signal (Still Fast)
