Term
| What is a ligand-gated receptor? |
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Definition
| A receptor that responds to neurotransmitters and allows ions (like Na+, K+, Cl-) to pass through. |
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Term
| What is a metabotropic receptor? |
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Definition
| A g-protein receptor. Initiates a series of intracellular events that ultimately result in ion channels opening. |
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Term
| Which 5 (important) ligand-gated / ionotropic receptors can you name? |
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Definition
[image]
- nACh
- AMPA
- NMDA
- GABA
- Serotonin |
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Term
| Which 3 (important) metabotropic receptors can you name? |
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Definition
[image]
- Glutamate
- Dopamine
- Serotonin |
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Term
| Name 5 functions of acetylcholine. |
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Definition
- Enhance long-term potentiation / learning
- Enhance selective attention
- Involved in generating neuronal oscillations
- Transmitter at the neuromuscular junction
- Transmitter of the parasympathetic NS (rest and digest) |
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Term
| What are 2 disorders of acetylcholine systems? |
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Definition
- Alzheimer disease: degeneration of ACh nuclei in basal forebrain
- Myasthenia gravis: antibodies against nACh receptors at neuromuscular junctions (muscle weakness, mostly in face but can be all over body) |
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Term
| Explain how acetylcholine is synthesised in cholinergic neurons. Indicate where in the neuron different synthesis steps take place. |
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Definition
In the presynaptic terminal, Glucose is turned into Acetyl-CoA (Coenzyme-A). This is combined with Choline to form Acetylcholine. Acetylcholine is transported to the synaptic cleft via a protein. In the synaptic cleft, Acetylcholine is broken up into Acetate and Choline. The Choline is transported back into the presynaptic terminal for future synthesis.
[image] |
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Term
| What can acetylcholine esterase blockers be useful for? |
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Definition
| They have a beneficial effect on attention, concentration, and performance in Alzheimer patients with mild forms of dementia. |
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Term
| What can NMDA blockers be useful for? |
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Definition
| They prevent over-excitation of glutamate (too much glutamate kills cells). |
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Term
| Describe where in a glutamatergic neurons glutamate is synthesised and explain what steps this process follows. |
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Definition
Glutamine is turned into glutamate in the presynaptic terminal. Glutamate is then transported to the synaptic cleft by a protein. Once release, the glutamate is absorbed by an glial (astrocyte) cell which turns it back into glutamine. The glutamine is then transported back into the presynaptic terminal for future synthesis.
[image] |
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Term
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Definition
- Maintain appropriate chemical environment for neuronal signalling
- Provides nutrients for neurons, promotes growth
- Reuptake of transmitters |
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Term
| What do oligodendrocytes do? |
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Definition
| - Provide myelin sheets along a neuron's axons |
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Term
| What do microglial cells do? |
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Definition
- They're like immune cells
- Remove damaged neurons and combats infections |
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Term
| What happens when you insert human astrocytes into a mouse brain? |
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Definition
- Learning time increases
- Number of errors made decreases |
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Term
| Which neurotransmitter activates NMDA and AMPA receptors? |
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Definition
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Term
| What are the similarities and differences between AMPA and NMDA receptors? |
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Definition
Both are ligand-gated / ionotropic. Both respond to glutamate binding to a ligand-binding domain.
AMPA:
- Depolarization, receptor opens. Current quickly wanes down.
NMDA:
- There is a magnesium block in the middle, so it requires extra depolarization before the receptor opens. This means the current slowly wanes down.
[image] |
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Term
| What do NMDA receptors play an important role in? |
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Definition
- Feedback processing
- Short-term memory
- Brain plasticity (learning and memory) |
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Term
| How do AMPA and NMDA receptors contribute to long-term potentiation? |
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Definition
- AMPA EPSPs (excitatory post-synaptic potentials) drive membrane potential to NMDA's threshold
- NMDA receptors open, influx of Ca2+
- Activation of various proteins
- Upregulation of AMPA receptors in membrane, increase in conductance
- Long lasting increase in EPSP amplitude (fires more easily / lowers firing threshold) |
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Term
| In which 2 brain areas does neurogenesis take place? |
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Definition
- Hippocampus
- Caudate nucleus |
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Term
| Rats that grow up in an enriched environment (a lot of possibility for learning) have neurons with more dendrites. What effect does this have on offspring? |
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Definition
| Offspring profits and also has neurons with more dendrites. |
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Term
| Describe where in a GABAergic neuron GABA is synthesised and explain what steps this process follows. |
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Definition
In the presynaptic terminal, glucose is turned into glutamate. Glutamate is then turned into GABA. GABA enters the synaptic cleft, and either lands on a GABA receptor or is transported to either to a glial cell or back into the presynaptic terminal where it can be broken down back into glucose.
[image] |
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Term
| What is the effect of GABA agonists? |
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Definition
| They work as sedatives (benzos or barbiturates). |
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Term
| What does the GABA system do? |
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Definition
- Maintains local balance of excitation via GABAergic inhibition
- This prevents excessive activity (like epilepsy)
- Pulsed inhibition generates neuronal oscillations (important for cognition) |
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Term
| What is the difference between benzodiazepine and barbiturates in terms of their effect on GABAergic channels? |
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Definition
- Benzodiazepine increases the frequency of GABA channels opening
- Barbiturates increase the amount of time a GABA channel stays open |
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Term
| Where in the brain is serotonin synthesised and where does it project to? |
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Definition
- Raphe nucleus
- All over the brain |
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Term
| What is the synthesis pathway for serotonin? |
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Definition
- Tryptophan
(Enzyme: Tryptophan-5-hydroxylase)
- 5-hydroxytryptophan
(Enzyme: Aromatic L-amino acid decarboxylase)
- Serotonin |
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Term
| What are the functions of serotonin? |
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Definition
- Modulates basic pyshcological functions (mood, appetite, sleep, sexuality)
- Implicated in depression
- Implicated in aggression |
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