Neurotransmission Flashcards

(88 cards)

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
Specialized structures developed to pass information
Synapse
26
Principal means of communication between neurons & between neurons and their effector organs (eg. muscle)
Synapse
27
Better fidelity of event transfer between neurons and relatively faster -Co-ordinated connection of large groups of neurons
Electrical synapse
28
Important method of signaling in retina, glial cells, astrocytes in CNS
Electrical synapse
29
The signal is rapid and amplified in the target -Neurons can integrate their response from multiple inputs
Chemical synapse
30
Can be manipulated pharmacologically -Widely used in the CNS and PNS
Chemical synapses
31
In an electrical synapse, direct physical connection allows flow of ions between cells through
Gap junctions
32
Transmit depolarizing and hyperpolarizing currents
Electrical synapse
33
In an electrical synapse, gap junctions are composed of many individual channels between
Cells
34
A low-resistance (high-conductance) pathway with near instantaneous (very short latency) transmission
Electrical synapse
35
Involves the synthesis and release of neurotransmitters or neuromodulators from the presynaptic neuron into the synaptic cleft
Chemical synapse
36
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
Post-synaptic Potential (PSP)
37
Synthesized by the presynaptic neuron and reside within synaptic terminals (usually in vesicles)
Neurotransmitters
38
Neurotransmitters bind to specific receptors on the
Postsynaptic membrane
39
Neurotransmitters are inactivated or removed from the
Postsynaptic Cleft
40
More than 90% of neurotransmission uses which 6 neurotransmitters?
Glutamate, GABA, Dopamine, Norepinephrine, Serotonin, and Acetylcholine
41
Protect neurotransmitters from degradation
Vesicles
42
Neurotransmitters are pushed into vesicles by a
V-type H+ ATPase proton pump
43
NOT stored in vesicles
Gaseous neurotransmitters
44
Depolarization of the membrane triggers voltage-gated Ca2+ channels to open and an influx of Ca2+ into the
Neuron occurs
45
Ca2+ then binds to synaptotagmin on the vesicle and pulls on the
SNARE complex
46
Ca2+ then binds to synaptotagmin on the vesicle and pulls on the SNARE complex to fuse the vesicle membrane with the
Presynaptic cell membrane
47
What are the two families of post-synaptic receptors?
Ligand-gated ion channels and G-protein-coupled receptors
48
Have very fast responses (less than 1 ms) -Neurotransmitter receptor is an integral part
Ligand-gated (ionotropic) ion channels
49
G-protein activation stimulates dissociation, which interacts with the ion channel
G-protein coupled (metabotropic) receptors
50
In G-protein coupled (metabotropic) receptors, the receptor is separate from the
Ion channel
51
Release of neurotransmitter may be regulated by
Pre-synaptic receptors
52
When the binding of transmitter inhibits its own further release. This is called
Autoreceptor feedback regulation
53
Astrocytes functionally support the neurons and strongly influence activity at a synapse. This forms a
Tripartite synapse
54
Provide physical and nutritional support and Communicate with neurons (to release gliotransmitters: D-serine, ATP)
Astrocytes
55
Sequester Na+ and K+ ions from the extracellular space- controlling concentrations -Metabolize neurotransmitters (GABA, glutamate, serotonin, etc.)
Astrocytes
56
The major excitatory neurotransmitter in the CNS- contained in approximately 50% neurons, and almost all excitatory neurons
Glutamate
57
For glutamate, what are the inotropic post-synaptic receptors?
NMDA (N-methyl-D-aspartate), kainate and AMPA -All excitatory
58
May be excitatory or inhibitory, depending on the state of the neuron
Glutamate metabotropic post-synaptic receptors
59
It is both a voltage-gated and ligand-gated Ca2+ ion channel
Glutamates NMDA receptor
60
At resting membrane potential, the NMDA receptor is blocked by
Mg2+
61
Uses the AMPA receptor and influx of Na+ to depolarize the membrane to remove the Mg2+ block
NMDA receptor
62
What are two drugs that influence the Glutamate (NMDAR) signaling?
Ketamine and PCP
63
Are both hallucinogens
Ketamine and PCP
64
NMDA activation in the presence of depolarization, enables
Ca2+ to enter the cell
65
Increased responsiveness of post-synaptic neurons after repeated stimulation of neurons (e.g., in hippocampus)
Glutamate Long-Term Potential (LTP)
66
Trauma and disease that impair ATP-generation can cause
Increased glutamate release or decreased glutamate re-uptake
67
In these situations, glutamate NMDA channels allow
Ca2+ leak into cells
68
Increased Ca2+ causes increased water uptake and stimulation of intracellular enzymes that degrade
Proteins, lipids. and nucleic acids
69
ALS, Alzheimer’s, tumors, oxygen deficiency, ischemia, trauma, and repeated seizures are examples of conditions thought to be associated with
Glutamate toxicity
70
Major inhibitory neurotransmitter of the CNS- contained in about 30% of CNS neurons
GABA
71
GABA is synthesized in the
Nucleus accumbens
72
The metabotropic GABA receptor is funcitonally linked to
K+ or Ca2+ ion channels
73
Are also ligand-gated Cl- channels similar to the GABAa receptor
Glycine receptors
74
What is the name of the 1. ) Inotropic GABA receptor 2. ) Metabotropic GABA receptor
1. ) GABAa | 2. ) GABAb
75
In the ANS, functions as neurotransmitter for postsynaptic sympathetic neurons at sites of action such as heart and blood vessels (α & β receptors)
Norepinephrine
76
In the CNS, acts as a neurotransmitter to neurons in brainstem regions as well as in the forebrain
Norepinephrine
77
Which two drugs influence NE signaling?
Amphetamines like adderall (+) and Methylphenidate (Ritalin) (+)
78
Involved in reward-motivated behavior and motor pathways
Dopamine
79
CNS- Neurons originate in brainstem regions (ventral tegmental area and substanstia nigra)
Dopamine
80
The reward pathway. Uses dopamine for addiction, schizophrenia and depression
Mesolimbic pathway
81
Uses dopamine as a neurotransmitter and is responsible for control of movement and Parkinson's disease
Nigrostriatal Pathway
82
Uses dopamine as the neurotransmitter and is responsible for Working memory, Schizophrenia, and ADHD
Mesocortical pathway
83
What are two drug types that influence dopamine signaling?
1. ) Anti-psychotics (-) | 2. ) Nicotine, cocaine, methamphetamine (+)
84
Main neurotransmitter in the PNS and ANS, but also has neuromodulator functions in CNS
Acetylcholine
85
Neurons originate in the basal forebrain (nucleus basalis) and the brainstem (dorsolateral midbrain-pons) and have widespread connections to the cortex
CNS neurons that use ACh
86
Involved in arousal, attention, memory and motivation
ACh in the CNS
87
Degenerates in Alzheimer's disease
Nucleus basalis
88
What are three drug types that influence ACh signaling in the CNS?
1. ) Nicotine (+) 2. ) Atropine (-) 3. ) Scopolamine (-)