Neuronal Transmission Flashcards

1
Q

What is the role of the neuronal membrane?

A

Separates the extracellular environment from the intracellular

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2
Q

What are the names of the membranes 2 sides?

A

Hydrophillic and hydrophobic

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3
Q

What is the NaK pump, and why does it happen?

A

Pumps 3 NA out and 2 K into the cell, and occurs to maintain the electrochemical gradient of the cell

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4
Q

What is the resting potential of a cell?

A

-70mV

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5
Q

What is the first movement during an action potential?

A

Na into the cell

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5
Q

What does the opening of K channels do?

A

Causes potassium to leave the cell and reversing the depolorisation

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6
Q

When will the cell be repolorised?

A

When the sodium channels close and potassium has left the cell

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7
Q

What is the rate law?

A

The size of the action potential stays the same, however the axons rate of firing can cause stronger or weaker contractions

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8
Q

Name the two types of synapse

A

Electrical and chemical

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9
Q

What are the three types of chemical synapse?

A

Axodendritic, axosomatic and axoaxonic

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10
Q

Name the stages in chemical transmission until CA influx

A
  1. Neurotransmitter synthesis
  2. Transport and storage
  3. Depolarisation/action potential
  4. Opening of voltage gated ion channels
  5. Ca influx into the cell
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11
Q

What is a neurotransmitter?

A

A type of chemical that is used to transmit information form the pre to the post synaptic neuron

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12
Q

Name the 2 types of receptor

A

Ionotropic and metabotropic

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13
Q

How do metabatropic receptors transmit a signal?

A

Through a second messenger system and activation of a G-protein

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14
Q

Following activation of the g-protein, GDP is exchanged for what?

A

GTP

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15
Q

After the exchange of GDP and GTP, what happens to the g-protein?

A

It splits and the subunits modulate other proteins such as enzymes

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16
Q

When does an EPSP happen?

A

Following depolarisation of the membrane

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17
Q

During inhibitory transmission, what charge of ions enters the cell?

A

Negative such as Cl-

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18
Q

Name the two processes that inactivate neurotransmitters

A

Reuptake receptors and deactivating enzymes

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19
Q

Autoreceptors use negative feedback to regulate synaptic transmission, what does this mean?

A

They inhibit further neurotransmitter release if there is too many in the synaptic cleft

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20
Q

Name the three categories of neurotransmitter

A
  1. Classical
  2. Neuropeptides
  3. Other small molecules
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21
Q

What is the differences in the synthesis of classical neurotransmitters and neuropeptides

A

Neurotransmitters are made in the terminal whereas neuropeptides are made in the soma

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22
Q

What is the effect of glutamate?

A

Excitatory, fluxing sodium into the cell

23
Q

What does glutamate bind to?

A

AMPA, NMDA and kainate

24
Q

The NMDA receptor also requires the binding of a o-agonist called what?

A

Glycine

25
Q

Name one non-competitive agonist at the NMDA receptor

A

PCP

26
Q

At resting state, why does the binding of glutamate not do anything at the NMDA receptor?

A

Due to the magnesium block, which is pushed out when the membrane is depolarised

27
Q

What can NMDA receptors be blocked by?

A

MK801

28
Q

What symptoms occur following blockage of the NMDA receptors?

A

Hallucinations like those of schiz

29
Q

When might glutamate excitotoxicity occur, and what causes it?

A

After a stroke or chronic stress, excessive influx of calcium into the cell

30
Q

What is the major inhibitory neurotransmitter called?

A

GABA

31
Q

How is GABA synthesised?

A

From glutamate

32
Q

Name a drug that increases GABA and how this leads to sedation/coma

A

GHB, increases the amount of available GABA at the synapse which leads to too much inhibitory transmission

33
Q

Name the four other drugs that bind to the GABAa receptor but not the GABA site

A
  1. Ethanol
  2. Neurosteroids
  3. Barbituates
    4.BZD
34
Q

What are anxiolytics?

A

Drugs that increase GABA activity

35
Q

What is the effect of the direct agonist, barbituates?

A

General depression of neuronal activity

36
Q

What type of agonist are BZDs?

A

Indirect agonists

37
Q

What is the difference between barbituates and BZDs?

A

The theraputic ration is different- easy to overdose on barbituates

38
Q

What drug blocks the effect of GABA?

A

Flumanezil

39
Q

Name the three neuromodulators

A

Dopamine, seretonin and acetylcholine

40
Q

What does it mean to be a neuromodulator?

A

They modulate neuronal activity and don’t carry any primary activity themselves

41
Q

Dopamine is involved in the nigrostriatal, mesolimbic and the mesocoritcal system, what role in behaviour do these systems play?

A

N = movement
ML = reinforcement and rewards
MC = planning and working memory

42
Q

What is the essential amino acid used to make dopamine?

A

Tyrosine

43
Q

Tyrosine is converted into what, that then becomes dopamine?

A

L-dopa

44
Q

Name the drug that impairs the storage of monoamines into the synaptic vesicles

A

Reserpine

45
Q

What does AMPT do?

A

It inactivates tyrosine, decreasing dopamine levels

46
Q

Dopamine transporters can reuptake dopamine, however it can also be enzymatically degraded by COMTs or?

A

Monoamine oxidases

47
Q

How do cocaine, amphetamines and methylphenidates affect dopamine?

A

They block the reuptake of dopamine into the terminals, leading to extended action of dopamine

48
Q

Selegiline and entacapone prevent the breakdown of dopamine which means what?

A

The pool of releaseable dopamine is increased and therefore more dopamine is released

49
Q

What amino acid is seretonin synthesised from?

A

Tryptophan

50
Q

What is the name for the SSRI that increases seretonin in the synapase (prozac medical name)?

A

Fluoxetine

51
Q

Until it was banned, what was fenfluramine used for?

A

Increasing the release of seretonin and inhibiting its uptake

52
Q

What affect does MDMA have on seretonin?

A

Increases the rate of seretonin release into the terminals

53
Q

Aceytlcholinesterase inhibitors, such as physostigmine, do what?

A

Block the breakdown of ACh, prolonging its actions in the synaptic cleft

54
Q

What is myasthenia gravis caused by?

A

A lack of ACh receptors in certain parts of the body

55
Q

Botunilinum toxins (botox) relaxes the muscles how?

A

By blocking the docking of vesicles that contain acetylcholine, to the muscles

56
Q

To inhibit the cholinergic neurons from firing, glycine is required, what toxins affect the release of glycine and therefore result in permanent muscle contraction
?

A

Tetanus toxins