Neurotransmission Flashcards

1
Q

Most neurons RMP is

A

-60 to -70 mV

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2
Q

The resting membrane potential is produced by which 3 things?

A
  1. ) Selective permeability of K+
  2. ) Osmotic and electrical forces
  3. ) Energy dependent Na+/K+ pump
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3
Q

A potential that does not reach threshold, however summation of these can reach threshold

A

Graded potential

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4
Q

Decrease over time and space

-can be excitatory or inhibitory

A

Graded potentials

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5
Q

The result of voltage-gated ion channels opening

-continued over time

A

Action potential

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6
Q

An all or none response

-Only excitatory

A

Action Potentials

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7
Q

Excitatory post-synaptic potentials (EPSPs) are examples of

A

Graded potentials

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8
Q

In EPSPs, depolarizing postsynaptic potentials = an influx of positive ions, usually a result from opening of

A

Na+ or Ca2+ channels

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9
Q

An influx of negative ions or efflux of positive ions

-Usually a result from opening Cl- or K+ channels

A

Hyperpolarization potentials

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10
Q

Hyperpolarization potentials are an example of an

-a form of graded potential

A

Inhibitory post-synaptic potential (IPSP)

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11
Q

Attenuate rapidly

A

Graded potentials

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12
Q

Graded potentials are summed and may reach threshold for an action potential if depolarization reaches the

A

Axon Hillock

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13
Q

Summation of graded potentials from one excitatory presynaptic neuron firing rapidly

A

Temporal Summation

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14
Q

Summation of graded potentials from two or more excitatory presynaptic neurons firing

A

Spatial summation

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15
Q

This depolarizes the neighboring membrane downstream, opening adjacent voltage-gated Na+ channels

A

Action potential propagation

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16
Q

Increase conduction velocity and membrane length constant

A

Larger axon diameter and increased myelination

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17
Q

Nodes of Ranvier are breaks in the myelination containing a very high concentration of voltage-gated

A

Na+ Channels

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18
Q

Action potentials ‘jump’ from one node to the next and are regenerated at each node. This concept is known as

A

Saltatory conduction

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19
Q

What are two types of demyelinating disease?

A
  1. ) Guillain-Barre Syndrome

2. ) Multiple Sclerosis

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20
Q

Damage to myelin of peripheral nerves, mainly motor nerves

-inflammatory process – viral exposure (1-2 weeks after infection)

A

Guillain-Barre Syndrome

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21
Q

Guillain-Barre syndrome is characterized by

A

Elevated protein in CSF

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22
Q

Autoimmune disorder caused by genetic predisposition and environmental exposure

A

Multiple Sclerosis (MS)

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23
Q

Characterized by multiple plaques of demyelinated CNS white matter

A

MS

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24
Q

More commonly effects optic nerve, deep cerebral white matter, cerebellar peduncles, brainstem, spinal cord

A

MS

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25
Q

Specialized structures developed to pass information

A

Synapse

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26
Q

Principal means of communication between neurons & between neurons and their effector organs (eg. muscle)

A

Synapse

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27
Q

Better fidelity of event transfer between neurons and relatively faster

-Co-ordinated connection of large groups of neurons

A

Electrical synapse

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28
Q

Important method of signaling in retina, glial cells, astrocytes in CNS

A

Electrical synapse

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29
Q

The signal is rapid and amplified in the target

-Neurons can integrate their response from multiple inputs

A

Chemical synapse

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30
Q

Can be manipulated pharmacologically

-Widely used in the CNS and PNS

A

Chemical synapses

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31
Q

In an electrical synapse, direct physical connection allows flow of ions between cells through

A

Gap junctions

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32
Q

Transmit depolarizing and hyperpolarizing currents

A

Electrical synapse

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33
Q

In an electrical synapse, gap junctions are composed of many individual channels between

A

Cells

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34
Q

A low-resistance (high-conductance) pathway with near instantaneous (very short latency) transmission

A

Electrical synapse

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35
Q

Involves the synthesis and release of neurotransmitters or neuromodulators from the presynaptic neuron into the synaptic cleft

A

Chemical synapse

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36
Q

In a chemical synapse, receptors on the post-synaptic neuron will signal a ion channel to open allowing the flow of ions through the channel resulting in a

A

Post-synaptic Potential (PSP)

37
Q

Synthesized by the presynaptic neuron and reside within synaptic terminals (usually in vesicles)

A

Neurotransmitters

38
Q

Neurotransmitters bind to specific receptors on the

A

Postsynaptic membrane

39
Q

Neurotransmitters are inactivated or removed from the

A

Postsynaptic Cleft

40
Q

More than 90% of neurotransmission uses which 6 neurotransmitters?

A

Glutamate, GABA, Dopamine, Norepinephrine, Serotonin, and Acetylcholine

41
Q

Protect neurotransmitters from degradation

A

Vesicles

42
Q

Neurotransmitters are pushed into vesicles by a

A

V-type H+ ATPase proton pump

43
Q

NOT stored in vesicles

A

Gaseous neurotransmitters

44
Q

Depolarization of the membrane triggers voltage-gated Ca2+ channels to open and an influx of Ca2+ into the

A

Neuron occurs

45
Q

Ca2+ then binds to synaptotagmin on the vesicle and pulls on the

A

SNARE complex

46
Q

Ca2+ then binds to synaptotagmin on the vesicle and pulls on the SNARE complex to fuse the vesicle membrane with the

A

Presynaptic cell membrane

47
Q

What are the two families of post-synaptic receptors?

A

Ligand-gated ion channels and G-protein-coupled receptors

48
Q

Have very fast responses (less than 1 ms)

-Neurotransmitter receptor is an integral part

A

Ligand-gated (ionotropic) ion channels

49
Q

G-protein activation stimulates dissociation, which interacts with the ion channel

A

G-protein coupled (metabotropic) receptors

50
Q

In G-protein coupled (metabotropic) receptors, the receptor is separate from the

A

Ion channel

51
Q

Release of neurotransmitter may be regulated by

A

Pre-synaptic receptors

52
Q

When the binding of transmitter inhibits its own further release. This is called

A

Autoreceptor feedback regulation

53
Q

Astrocytes functionally support the neurons and strongly influence activity at a synapse. This forms a

A

Tripartite synapse

54
Q

Provide physical and nutritional support and Communicate with neurons (to release gliotransmitters: D-serine, ATP)

A

Astrocytes

55
Q

Sequester Na+ and K+ ions from the extracellular space- controlling concentrations

-Metabolize neurotransmitters (GABA, glutamate, serotonin, etc.)

A

Astrocytes

56
Q

The major excitatory neurotransmitter in the CNS- contained in approximately 50% neurons, and almost all excitatory neurons

A

Glutamate

57
Q

For glutamate, what are the inotropic post-synaptic receptors?

A

NMDA (N-methyl-D-aspartate), kainate and AMPA

-All excitatory

58
Q

May be excitatory or inhibitory, depending on the state of the neuron

A

Glutamate metabotropic post-synaptic receptors

59
Q

It is both a voltage-gated and ligand-gated Ca2+ ion channel

A

Glutamates NMDA receptor

60
Q

At resting membrane potential, the NMDA receptor is blocked by

A

Mg2+

61
Q

Uses the AMPA receptor and influx of Na+ to depolarize the membrane to remove the Mg2+ block

A

NMDA receptor

62
Q

What are two drugs that influence the Glutamate (NMDAR) signaling?

A

Ketamine and PCP

63
Q

Are both hallucinogens

A

Ketamine and PCP

64
Q

NMDA activation in the presence of depolarization, enables

A

Ca2+ to enter the cell

65
Q

Increased responsiveness of post-synaptic neurons after repeated stimulation of neurons (e.g., in hippocampus)

A

Glutamate Long-Term Potential (LTP)

66
Q

Trauma and disease that impair ATP-generation can cause

A

Increased glutamate release or decreased glutamate re-uptake

67
Q

In these situations, glutamate NMDA channels allow

A

Ca2+ leak into cells

68
Q

Increased Ca2+ causes increased water uptake and stimulation of intracellular enzymes that degrade

A

Proteins, lipids. and nucleic acids

69
Q

ALS, Alzheimer’s, tumors, oxygen deficiency, ischemia, trauma, and repeated seizures are examples of conditions thought to be associated with

A

Glutamate toxicity

70
Q

Major inhibitory neurotransmitter of the CNS- contained in about 30% of CNS neurons

A

GABA

71
Q

GABA is synthesized in the

A

Nucleus accumbens

72
Q

The metabotropic GABA receptor is funcitonally linked to

A

K+ or Ca2+ ion channels

73
Q

Are also ligand-gated Cl- channels similar to the GABAa receptor

A

Glycine receptors

74
Q

What is the name of the

  1. ) Inotropic GABA receptor
  2. ) Metabotropic GABA receptor
A
  1. ) GABAa

2. ) GABAb

75
Q

In the ANS, functions as neurotransmitter for postsynaptic sympathetic neurons at sites of action such as heart and blood vessels (α & β receptors)

A

Norepinephrine

76
Q

In the CNS, acts as a neurotransmitter to neurons in brainstem regions as well as in the forebrain

A

Norepinephrine

77
Q

Which two drugs influence NE signaling?

A

Amphetamines like adderall (+) and Methylphenidate (Ritalin) (+)

78
Q

Involved in reward-motivated behavior and motor pathways

A

Dopamine

79
Q

CNS- Neurons originate in brainstem regions (ventral tegmental area and substanstia nigra)

A

Dopamine

80
Q

The reward pathway. Uses dopamine for addiction, schizophrenia and depression

A

Mesolimbic pathway

81
Q

Uses dopamine as a neurotransmitter and is responsible for control of movement and Parkinson’s disease

A

Nigrostriatal Pathway

82
Q

Uses dopamine as the neurotransmitter and is responsible for Working memory, Schizophrenia, and ADHD

A

Mesocortical pathway

83
Q

What are two drug types that influence dopamine signaling?

A
  1. ) Anti-psychotics (-)

2. ) Nicotine, cocaine, methamphetamine (+)

84
Q

Main neurotransmitter in the PNS and ANS, but also has neuromodulator functions in CNS

A

Acetylcholine

85
Q

Neurons originate in the basal forebrain (nucleus basalis) and the brainstem (dorsolateral midbrain-pons) and have widespread connections to the cortex

A

CNS neurons that use ACh

86
Q

Involved in arousal, attention, memory and motivation

A

ACh in the CNS

87
Q

Degenerates in Alzheimer’s disease

A

Nucleus basalis

88
Q

What are three drug types that influence ACh signaling in the CNS?

A
  1. ) Nicotine (+)
  2. ) Atropine (-)
  3. ) Scopolamine (-)