Neurons and Neurotransmitters 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
