Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

2.2 Brain & Behaviour > 03. Neuronal transmission I > Flashcards

03. Neuronal transmission I Flashcards

(51 cards)

Start Studying
1
Q

Dendrites

A

Receive information

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Soma / cell body

A

Main part of neuron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Axon

A

Send information

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Terminal boutons

A

AKA axon terminals
- Where the axon meets a neighbouring cell’s dendrites to form a synapse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is an electrical synapse?

A
  • uncommon in mammals
  • ions move freely (through proteins called ‘connexins’)
  • the junction between the neurons (gap junction) is tiny - 3nm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a chemical synapse?

A
  • most common (mammals)
  • communication done through neurotransmitters
  • junction between neurons (synaptic cleft) is 20-50nm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What was the first experimental evidence for chemical transmission

A

Loewi (1920s)
- vagus stimulation -> fluid removed -> injected into another creature -> slowed down their heart rate
- proved that communication can be transferred between creatures and is therefore chemical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

In synapses, the axon can connect to 3 different places:

A
  • Axodendritic (most) -> axon connects to dendrite
  • Axosomatic -> axon connects to soma
  • Axoaxonic -> axon connects to axon
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the criteria for being a neurotransmitter?

A
  • synthesised presynaptically
  • released after elec stimulation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Synapses work via receptors. Receptors have varying:

A

kinetics - rate of binding and channel gating
selectivity - what ions are fluxed
conductance - rate of flux

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Ionotropic receptors:
Excitatory transmission

A

Ion channel opens -> influx of cations (Na+) -> depolarisation -> EPSP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Ionotropic receptors:
Inhibitory transmission

A

Ion channel opens -> influx of anions (Cl-) -> hyperpolarisation -> IPSP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Metabotropic receptors

A

Same process of inhibition and excitation, but influx of ions is triggered by the ligand-binding G-protein coupled receptor (GPCR) which causes a cascade of reactions inside the cell (second messengers)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Categories of neurotransmitters include:

A

Amino acids
Monoamines
Acetylcholine
Neuropeptides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Glutamatergic receptors include:

A

Glutamate (mGluR), NMDA, AMPA, Kainate

m in mGluR = metabotropic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the process of glutamate production and release?

A
  • glutamate is synthesised in nerve terminal from glucose or glutamine
  • stored in vesicles
  • released by exocytosis
    (Ca2+ required)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the agonists and antagonists for the NMDA receptor?

A

Agonist - NMDA & glutamate
Antagonist - APV / AP5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the agonists and antagonists for the AMPA receptor?

A

Agonist - AMPA & glutamate
Antagonist - CNQX

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the agonists and antagonists for the Kainate receptor?

A

Agonist - Kainate & glutamate
Antagonist - CNQX

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the NMDA receptor’s competitive and non-competitive agonists and antagonists? What is the co-agonist?

A

agonist: glutamate
competitive agonist: NMDA
competitive antagonist: APV / AP5
non-competitive agonist: PCP
co-agonist: glycine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

So how are NMDA receptors activated?

Study These Flashcards
A
  • co-activation from glutamate and glycine & low enough membrane voltage
  • this allows the channel to open and Mg2+ to be moved which unblocks the channel pore.
  • glutamate alone opens the channel but doesn’t move Mg2+
22
Q

What causes NMDA dysregulation?

Study These Flashcards
A
  • excessive glutamate (glutamate excitotoxicity)
  • excessive Ca2+ influx, activating calcium-dependent proteases and phospholipases that break down parts of the cell
  • often after stroke or chronic stress
23
Q

AMPA vs NMDA

Study These Flashcards
A
  • different kinetics: NMDA opens slower
  • NMDA channels are permeable to Ca2+, Na+ and K+
  • AMPA channels are permeable to Ca2+ and Zn2+
24
Q

What is GABA?

Study These Flashcards
A
  • gamma aminobutyric acid
  • inhibitory transmitter
  • activates GABAA (ionotropic) and GABAB (metabotropic)
25
GABAA receptor
- ionotropic - ligand-gated Cl- channel
26
GABAB receptor
- metabotropic - GPCR coupled to K+ or Ca2+ - slow IPSPs
27
Too much GABA...
- leads to over-inhibition, which can cause sedation and coma - means that drugs that increase GABA transmission can treat epilepsy
28
What is GHB (gamma-hydroxybutyrate)?
A date rape drug Metabolism converts it into GABA This leads to unconsciousness and even coma
29
What can alcohol cause?
Unconsciousness, coma, and death (although often one passes out before ingesting lethal dose)
30
What drugs bind at the GABAA receptor and compete with GABA?
Agonists - Muscimol Antagonists - bicuculine, picrotoxin
31
What drugs bind at the GABAA receptor and don't compete with GABA?
Agonists - Alcohol - Barbiturates Indirect agonist - Benzodiazepines (BDZ) (also anti-convulsant) Antagonist - Flumazenil (can reverse sedation from BDZ overdose) ## Footnote Drugs decreasing GABA activity increase anxiety (anxiogenic) (result: more Cl- current, more inhibition, stronger IPSPs)
32
What do drugs that increase GABA activity do?
Reduce anxiety Change the kinetics of the GABA receptor
33
Benzodiazepines history
Discovered in the 1960s First one was chlordiazepoxide (Librium), which was replaced with diazepam (Valium) to treat anxiety
34
What do Benzodiazepines do?
They act as: - Anxiolytic - Anticonvulsant - Sedative - Muscle relaxant - Amnestic They are fast-acting but may cause dependence Effects are strengthened by alcohol
35
What is a neuromodulator?
A type of neurotransmitter that affects the neuronal response to other neurotransmitters They do not carry any primary info themselves
36
Examples of neuromodulators include:
- dopamine - serotonin - histamine - neuropeptides
37
What are systems within the Dopaminergic system?
- Nigrostriatal - Mesolimbic - Mesocortical
38
What does the nigrostriatal system do (1) and what area is it found in (2)?
1. has a role in movement - dysfunction causes Parkinson's & Huntington's disease 2. projections from the substantia nigra to neostriatum (caudate and putamen)
39
What does the mesolimbic system do (1) and what area is it found in (2)?
1. reinforcement/reward (so has a role in addiction) 2. projections from the ventral tegmental area to nucleus accumbens (NAcc))
40
What does the mesocortical system do (1) and what area is it found in (2)?
1. working memory/planning (dysfunction: schizophrenia) 2. projections from the VTA to prefrontal cortex
41
What is the process of dopamine synthesis?
Tyrosine (essential amino acid obtained in diet) -> catalysed by tyrosine hydroxylase (TH) (rate limiting step) -> L-Dopa -> catalysed by dopa decarboxylase -> Dopamine It is then stored in vesicles
42
What drugs affect dopamine synthesis?
Reserpine - impairs vesicle storage (empty vesicles -> no neurotransmission)
43
What is the process of dopamine release?
Ca2+ dependent exocytosis
44
What is the process of dopamine reuptake/metabolism?
- Transmission is terminated by Dopamine transporters (DATs) - They are transporters that respond to electrochemical gradient - This occurs in the cytoplasm - Then dopamine is repacked into vesicles or metabolised
45
Drugs that affect dopamine release and reuptake
Cocaine, Amphetamine and Methylphenidate (Ritalin) - psychostimulants - block reuptake of monoamines, inc. dopamine Selegiline – Monoamine oxidase B inhibitor (prevents breakdown of catecholamines)
46
What is the Serotonergic system?
Nine raphe nuclei (in brain stem), each projecting to a different part of the brain Descending projections to cerebellum and spinal cord (pain) The dorsal and medial raphe project throughout the cerebral cortex. Functions: mood, sleep, pain, emotion, appetite
47
What is the process of serotonin synthesis?
Tryptophan (dietary amino acid) -> converted via tryptophan hydroxylase (rate limiting) -> makes 5-HTP -> converted via aromatic amino acid decarboxylase -> Serotonin It is then stored in vesicles
48
What is the process of serotonin release?
Ca2+ dependent exocytosis
49
What is the process of serotonin reuptake/metabolism?
- transmission terminated by SERTs (serotonin transporters) - serotonin is degraded by MAOs in the cytoplasm
50
What drugs affect serotonin reuptake?
Fluoxetine (Prozac) is an SSRI and blocks reuptake of serotonin MDMA (ecstasy) causes increased empathy and euphoria and makes serotonin transporters (SERT) work in reverse - more serotonin is released Monoamine oxidase inhibitors boost monoamines
51
How does Ca2+ mediated exocytosis work?
Presynaptic membrane depolarises -> influx of Ca2+ (through voltage-gated channels) -> Ca2+ causes exocytosis of vesicles

2.2 Brain & Behaviour (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions