e4 neurotransmitters and synapses
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Assessment Statements Obj
E41 State that some neurotransmitters excite postsynaptic transmission and others inhibit postsynaptic transmission 1
E42 Explain how decision-making in the CNS can result from the interaction between the activities excitatory and inhibitory presynapatic neurons at synapses 3
E43 Explain how psychoactive drugs affect the brain and personality by either increasing or decreasing postsynaptic transmission 3
E44List three examples of excitatory and three examples of inhibitory psychoactive drugs
bull Excitatory nicotine cocaine amphetaminesbull Inhibitory benzodiazepines alcohol tetrahydrocannabinol (THC)
1
E45 Explain the effects of cocaine and THC in terms of their action at synapses in the brain 3
E46 Discuss the causes of addiction including genetic predisposition social factors and dopamine secretion 3
Assessment statements from Online IB Biology Subject GuideCommand terms httpi-biologynetibdpbiocommand-terms
Be sure you have a solid understanding of action potentials and synapses as you work through this subtopic
httpwwwyoutubecomwatchv=LT3VKAr4roo
httplearngeneticsutaheducontentaddictionrewardneurontalkhtml
Work through this tutorial
Communication via Synapses
Synapses are a fundamental part of neural pathways as they regulate decision-making in terms of exciting or inhibiting the post-synaptic neurons
Review bull Action potentials (AP) reach terminal
bud of the pre-synaptic neuron bull Neurotransmitters (NT) chemical
messengers diffuse across the synapse to bind with receptors on the post-synaptic membrane
Neurotransmitters are bull Excitatory which means they excite the
post-synaptic neuron (contributing to depolarisation and propagation of the AP
OR bull Inhibitory hyperpolarising the post-
synaptic neuron and preventing AP
Neurotransmitters can be excitatory or inhibitoryNeurotransmitters (NT) are proteins bull diffuse across the synaptic cleftbull bind with a receptor on the post-synaptic neuron
Whether or not the post-synaptic neuron propagates the action potential depends on bull Which NT diffuses acrossbull Which receptors they bind tobull Which ions flow inout of the post-synaptic neuronbull Whether or not depolarisation reaches threshold
-70mv
0mv
time
threshold
resting
depolarisation
hyperpolarisation
Excitatory NTs cause depolarisationbull eg ACh dopaminebull NT binds Na+ channels open Na+ rushes inbull Membrane potential depolarises AP propagated
Inhibitory NTs cause hyperpolarisationbull eg GABA dopamine (on different pathways)bull NT binds to receptorbull K+ channels open K+ rushes outbull OR Cl- channels open Cl- rushes inbull Membrane potential become more negativebull Action potential is prevented from propagating
httpisgdJellinek
This is a useful example of an inhibitory neurotransmitter
httpwwwyoutubecomwatchv=-pfG6yHAQ5U
Decision-making in the Central Nervous System (CNS)
axon
synapse
axon hillock
actio
n po
tenti
al
Diagram adapted from httphscuweacuksynapses_neurosummationhtm
The axons of many pre-synaptic neurons feed into the dendrites of one post-synaptic
neurons via synapses
The lsquodecisionrsquo whether or not to propagate the action potential along the axon of the
post-synaptic neuron takes place in a region of the cell body
called the axon hillock
This is achieved through summationof the incoming impulses If the total
impulse reaches thresholdthe post-synaptic neuron depolarises and
the action potential is propagated
If the sum does not reach threshold the AP is not propagated
There are two main methods of summation
temporal and spatial
Decision-making in the Central Nervous System (CNS)
Diagram adapted from httphscuweacuksynapses_neurosummationhtm
Test out temporal and spatial summation Temporal summationbull Action potentials arrive in rapid
successionbull Depolarisation in the axon hillock is
summativebull If it reaches threshold before
repolarisation the AP is propagated
Spatial summationbull Action potentials arrive simultaneously
from multiple sourcesbull Some neurotransmitters are excitatory
(increasing depolarisation)bull Other NTs are inhibitory
(hyperpolarising) bull Summation in the axon hillock is
summative bull If it reaches threshold the AP is
propagated
httpwwwjellinekeubrainindexhtmlKeepThis=trueampTB_iframe=trueampheight=588ampwidth=672
How do psychoactive drugs affect the brain
Work through the excellent animations and explanations from httpwwwjellinekeu
Before thinking about how drugs affect the synapses be sure you understand how they work and are reset bull Some NTs have a normal excitatory functionbull Other NTs have a normal inhibitory function
In general psychoactive drugs can 1 Increase or decrease the release of NTs (eg
THC ndash cannabis)2 Breakdown re-uptake proteins which are
responsible for returned used components of NTs to the pre-synaptic neuron (ready to use again)
3 Block re-uptake proteins (egcocaine)4 Mimic or block NTs binding to the receptors
on post-synaptic membranes5 Inhibit production of new NTs
Excitatory drugs increase post-synaptic transmission
Examples bull Nicotine amphetamines cocaine
What is the effect of cocaine Normal bull Dopamine acts as excitatory NTbull Dopamine is re-uptaken by pumps on the pre-
synaptic membrane
With Cocainebull Cocaine blocks re-uptake pumpsbull Dopamine remains in synaptic cleftbull More dopamine continues to be releasedbull Summative increase in post-synaptic transmission
Effects on mood bull Dopamine is involved in reward pathways
enhancing feelings of pleasurebull Longer-lasting feelings as dopamine is not re-
uptaken
Effects on behaviourbull feelings of euphoriabull increased energy and alertnessbull highly addictivebull association with depression as body reduces
production of own dopamine over timehttpisgdJellinek
httpisgdJellinek
Inhibitory drugs decrease post-synaptic transmission
Examples bull Alcohol benzodiazapines THC
What is the effect of tetrahydrocannibol (THC) Normal bull Dopamine release is moderated (inhibited) by GABA
With THCbull THC mimics cannabinoids and inhibits GABA release
by binding to cannabinoid receptorsbull GABA cannot inhibit dopamine releasebull More dopamine is released
Effects on mood bull Dopamine is involved in reward pathways
enhancing feelings of pleasurebull Not as extreme release of dopamine as with
cocaine but still higher than normal
Effects on behaviourbull intoxicationbull hungerbull memory impairmentbull potential dependency
httpoutreachmcbharvardeduanimationssynapseswf
httpthebrainmcgillcaintermediairephp
A scale of harm for drugsWhich dots represent bull tobaccobull alcoholbull heroinbull cocainebull THC cannabisbull ecstasy
Drag the red dot to point you think represents alcohol
How can drugs cause physical harm
How can drug use lead to addiction (dependency)
What factors contribute to development of addiction
ActivePrompt linkhttpactivepromptherokuappcomSQSNK or httpisgddrugscaleprompt httpactivepromptherokuappcomTYYBH
httpwwwyoutubecomwatchv=bCChf2WHNE4
This is a Creative Commons presentation It may be linked and embedded but not sold or re-hosted
Please consider a donation to charity via Biology4GoodClick here for more information about Biology4Good charity donations
IBiologyStephen
- Slide 1
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- Slide 18
- Slide 19
- Slide 20
-
httpwwwyoutubecomwatchv=LT3VKAr4roo
httplearngeneticsutaheducontentaddictionrewardneurontalkhtml
Work through this tutorial
Communication via Synapses
Synapses are a fundamental part of neural pathways as they regulate decision-making in terms of exciting or inhibiting the post-synaptic neurons
Review bull Action potentials (AP) reach terminal
bud of the pre-synaptic neuron bull Neurotransmitters (NT) chemical
messengers diffuse across the synapse to bind with receptors on the post-synaptic membrane
Neurotransmitters are bull Excitatory which means they excite the
post-synaptic neuron (contributing to depolarisation and propagation of the AP
OR bull Inhibitory hyperpolarising the post-
synaptic neuron and preventing AP
Neurotransmitters can be excitatory or inhibitoryNeurotransmitters (NT) are proteins bull diffuse across the synaptic cleftbull bind with a receptor on the post-synaptic neuron
Whether or not the post-synaptic neuron propagates the action potential depends on bull Which NT diffuses acrossbull Which receptors they bind tobull Which ions flow inout of the post-synaptic neuronbull Whether or not depolarisation reaches threshold
-70mv
0mv
time
threshold
resting
depolarisation
hyperpolarisation
Excitatory NTs cause depolarisationbull eg ACh dopaminebull NT binds Na+ channels open Na+ rushes inbull Membrane potential depolarises AP propagated
Inhibitory NTs cause hyperpolarisationbull eg GABA dopamine (on different pathways)bull NT binds to receptorbull K+ channels open K+ rushes outbull OR Cl- channels open Cl- rushes inbull Membrane potential become more negativebull Action potential is prevented from propagating
httpisgdJellinek
This is a useful example of an inhibitory neurotransmitter
httpwwwyoutubecomwatchv=-pfG6yHAQ5U
Decision-making in the Central Nervous System (CNS)
axon
synapse
axon hillock
actio
n po
tenti
al
Diagram adapted from httphscuweacuksynapses_neurosummationhtm
The axons of many pre-synaptic neurons feed into the dendrites of one post-synaptic
neurons via synapses
The lsquodecisionrsquo whether or not to propagate the action potential along the axon of the
post-synaptic neuron takes place in a region of the cell body
called the axon hillock
This is achieved through summationof the incoming impulses If the total
impulse reaches thresholdthe post-synaptic neuron depolarises and
the action potential is propagated
If the sum does not reach threshold the AP is not propagated
There are two main methods of summation
temporal and spatial
Decision-making in the Central Nervous System (CNS)
Diagram adapted from httphscuweacuksynapses_neurosummationhtm
Test out temporal and spatial summation Temporal summationbull Action potentials arrive in rapid
successionbull Depolarisation in the axon hillock is
summativebull If it reaches threshold before
repolarisation the AP is propagated
Spatial summationbull Action potentials arrive simultaneously
from multiple sourcesbull Some neurotransmitters are excitatory
(increasing depolarisation)bull Other NTs are inhibitory
(hyperpolarising) bull Summation in the axon hillock is
summative bull If it reaches threshold the AP is
propagated
httpwwwjellinekeubrainindexhtmlKeepThis=trueampTB_iframe=trueampheight=588ampwidth=672
How do psychoactive drugs affect the brain
Work through the excellent animations and explanations from httpwwwjellinekeu
Before thinking about how drugs affect the synapses be sure you understand how they work and are reset bull Some NTs have a normal excitatory functionbull Other NTs have a normal inhibitory function
In general psychoactive drugs can 1 Increase or decrease the release of NTs (eg
THC ndash cannabis)2 Breakdown re-uptake proteins which are
responsible for returned used components of NTs to the pre-synaptic neuron (ready to use again)
3 Block re-uptake proteins (egcocaine)4 Mimic or block NTs binding to the receptors
on post-synaptic membranes5 Inhibit production of new NTs
Excitatory drugs increase post-synaptic transmission
Examples bull Nicotine amphetamines cocaine
What is the effect of cocaine Normal bull Dopamine acts as excitatory NTbull Dopamine is re-uptaken by pumps on the pre-
synaptic membrane
With Cocainebull Cocaine blocks re-uptake pumpsbull Dopamine remains in synaptic cleftbull More dopamine continues to be releasedbull Summative increase in post-synaptic transmission
Effects on mood bull Dopamine is involved in reward pathways
enhancing feelings of pleasurebull Longer-lasting feelings as dopamine is not re-
uptaken
Effects on behaviourbull feelings of euphoriabull increased energy and alertnessbull highly addictivebull association with depression as body reduces
production of own dopamine over timehttpisgdJellinek
httpisgdJellinek
Inhibitory drugs decrease post-synaptic transmission
Examples bull Alcohol benzodiazapines THC
What is the effect of tetrahydrocannibol (THC) Normal bull Dopamine release is moderated (inhibited) by GABA
With THCbull THC mimics cannabinoids and inhibits GABA release
by binding to cannabinoid receptorsbull GABA cannot inhibit dopamine releasebull More dopamine is released
Effects on mood bull Dopamine is involved in reward pathways
enhancing feelings of pleasurebull Not as extreme release of dopamine as with
cocaine but still higher than normal
Effects on behaviourbull intoxicationbull hungerbull memory impairmentbull potential dependency
httpoutreachmcbharvardeduanimationssynapseswf
httpthebrainmcgillcaintermediairephp
A scale of harm for drugsWhich dots represent bull tobaccobull alcoholbull heroinbull cocainebull THC cannabisbull ecstasy
Drag the red dot to point you think represents alcohol
How can drugs cause physical harm
How can drug use lead to addiction (dependency)
What factors contribute to development of addiction
ActivePrompt linkhttpactivepromptherokuappcomSQSNK or httpisgddrugscaleprompt httpactivepromptherokuappcomTYYBH
httpwwwyoutubecomwatchv=bCChf2WHNE4
This is a Creative Commons presentation It may be linked and embedded but not sold or re-hosted
Please consider a donation to charity via Biology4GoodClick here for more information about Biology4Good charity donations
IBiologyStephen
- Slide 1
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Neurotransmitters can be excitatory or inhibitoryNeurotransmitters (NT) are proteins bull diffuse across the synaptic cleftbull bind with a receptor on the post-synaptic neuron
Whether or not the post-synaptic neuron propagates the action potential depends on bull Which NT diffuses acrossbull Which receptors they bind tobull Which ions flow inout of the post-synaptic neuronbull Whether or not depolarisation reaches threshold
-70mv
0mv
time
threshold
resting
depolarisation
hyperpolarisation
Excitatory NTs cause depolarisationbull eg ACh dopaminebull NT binds Na+ channels open Na+ rushes inbull Membrane potential depolarises AP propagated
Inhibitory NTs cause hyperpolarisationbull eg GABA dopamine (on different pathways)bull NT binds to receptorbull K+ channels open K+ rushes outbull OR Cl- channels open Cl- rushes inbull Membrane potential become more negativebull Action potential is prevented from propagating
httpisgdJellinek
This is a useful example of an inhibitory neurotransmitter
httpwwwyoutubecomwatchv=-pfG6yHAQ5U
Decision-making in the Central Nervous System (CNS)
axon
synapse
axon hillock
actio
n po
tenti
al
Diagram adapted from httphscuweacuksynapses_neurosummationhtm
The axons of many pre-synaptic neurons feed into the dendrites of one post-synaptic
neurons via synapses
The lsquodecisionrsquo whether or not to propagate the action potential along the axon of the
post-synaptic neuron takes place in a region of the cell body
called the axon hillock
This is achieved through summationof the incoming impulses If the total
impulse reaches thresholdthe post-synaptic neuron depolarises and
the action potential is propagated
If the sum does not reach threshold the AP is not propagated
There are two main methods of summation
temporal and spatial
Decision-making in the Central Nervous System (CNS)
Diagram adapted from httphscuweacuksynapses_neurosummationhtm
Test out temporal and spatial summation Temporal summationbull Action potentials arrive in rapid
successionbull Depolarisation in the axon hillock is
summativebull If it reaches threshold before
repolarisation the AP is propagated
Spatial summationbull Action potentials arrive simultaneously
from multiple sourcesbull Some neurotransmitters are excitatory
(increasing depolarisation)bull Other NTs are inhibitory
(hyperpolarising) bull Summation in the axon hillock is
summative bull If it reaches threshold the AP is
propagated
httpwwwjellinekeubrainindexhtmlKeepThis=trueampTB_iframe=trueampheight=588ampwidth=672
How do psychoactive drugs affect the brain
Work through the excellent animations and explanations from httpwwwjellinekeu
Before thinking about how drugs affect the synapses be sure you understand how they work and are reset bull Some NTs have a normal excitatory functionbull Other NTs have a normal inhibitory function
In general psychoactive drugs can 1 Increase or decrease the release of NTs (eg
THC ndash cannabis)2 Breakdown re-uptake proteins which are
responsible for returned used components of NTs to the pre-synaptic neuron (ready to use again)
3 Block re-uptake proteins (egcocaine)4 Mimic or block NTs binding to the receptors
on post-synaptic membranes5 Inhibit production of new NTs
Excitatory drugs increase post-synaptic transmission
Examples bull Nicotine amphetamines cocaine
What is the effect of cocaine Normal bull Dopamine acts as excitatory NTbull Dopamine is re-uptaken by pumps on the pre-
synaptic membrane
With Cocainebull Cocaine blocks re-uptake pumpsbull Dopamine remains in synaptic cleftbull More dopamine continues to be releasedbull Summative increase in post-synaptic transmission
Effects on mood bull Dopamine is involved in reward pathways
enhancing feelings of pleasurebull Longer-lasting feelings as dopamine is not re-
uptaken
Effects on behaviourbull feelings of euphoriabull increased energy and alertnessbull highly addictivebull association with depression as body reduces
production of own dopamine over timehttpisgdJellinek
httpisgdJellinek
Inhibitory drugs decrease post-synaptic transmission
Examples bull Alcohol benzodiazapines THC
What is the effect of tetrahydrocannibol (THC) Normal bull Dopamine release is moderated (inhibited) by GABA
With THCbull THC mimics cannabinoids and inhibits GABA release
by binding to cannabinoid receptorsbull GABA cannot inhibit dopamine releasebull More dopamine is released
Effects on mood bull Dopamine is involved in reward pathways
enhancing feelings of pleasurebull Not as extreme release of dopamine as with
cocaine but still higher than normal
Effects on behaviourbull intoxicationbull hungerbull memory impairmentbull potential dependency
httpoutreachmcbharvardeduanimationssynapseswf
httpthebrainmcgillcaintermediairephp
A scale of harm for drugsWhich dots represent bull tobaccobull alcoholbull heroinbull cocainebull THC cannabisbull ecstasy
Drag the red dot to point you think represents alcohol
How can drugs cause physical harm
How can drug use lead to addiction (dependency)
What factors contribute to development of addiction
ActivePrompt linkhttpactivepromptherokuappcomSQSNK or httpisgddrugscaleprompt httpactivepromptherokuappcomTYYBH
httpwwwyoutubecomwatchv=bCChf2WHNE4
This is a Creative Commons presentation It may be linked and embedded but not sold or re-hosted
Please consider a donation to charity via Biology4GoodClick here for more information about Biology4Good charity donations
IBiologyStephen
- Slide 1
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- Slide 4
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- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
-
This is a useful example of an inhibitory neurotransmitter
httpwwwyoutubecomwatchv=-pfG6yHAQ5U
Decision-making in the Central Nervous System (CNS)
axon
synapse
axon hillock
actio
n po
tenti
al
Diagram adapted from httphscuweacuksynapses_neurosummationhtm
The axons of many pre-synaptic neurons feed into the dendrites of one post-synaptic
neurons via synapses
The lsquodecisionrsquo whether or not to propagate the action potential along the axon of the
post-synaptic neuron takes place in a region of the cell body
called the axon hillock
This is achieved through summationof the incoming impulses If the total
impulse reaches thresholdthe post-synaptic neuron depolarises and
the action potential is propagated
If the sum does not reach threshold the AP is not propagated
There are two main methods of summation
temporal and spatial
Decision-making in the Central Nervous System (CNS)
Diagram adapted from httphscuweacuksynapses_neurosummationhtm
Test out temporal and spatial summation Temporal summationbull Action potentials arrive in rapid
successionbull Depolarisation in the axon hillock is
summativebull If it reaches threshold before
repolarisation the AP is propagated
Spatial summationbull Action potentials arrive simultaneously
from multiple sourcesbull Some neurotransmitters are excitatory
(increasing depolarisation)bull Other NTs are inhibitory
(hyperpolarising) bull Summation in the axon hillock is
summative bull If it reaches threshold the AP is
propagated
httpwwwjellinekeubrainindexhtmlKeepThis=trueampTB_iframe=trueampheight=588ampwidth=672
How do psychoactive drugs affect the brain
Work through the excellent animations and explanations from httpwwwjellinekeu
Before thinking about how drugs affect the synapses be sure you understand how they work and are reset bull Some NTs have a normal excitatory functionbull Other NTs have a normal inhibitory function
In general psychoactive drugs can 1 Increase or decrease the release of NTs (eg
THC ndash cannabis)2 Breakdown re-uptake proteins which are
responsible for returned used components of NTs to the pre-synaptic neuron (ready to use again)
3 Block re-uptake proteins (egcocaine)4 Mimic or block NTs binding to the receptors
on post-synaptic membranes5 Inhibit production of new NTs
Excitatory drugs increase post-synaptic transmission
Examples bull Nicotine amphetamines cocaine
What is the effect of cocaine Normal bull Dopamine acts as excitatory NTbull Dopamine is re-uptaken by pumps on the pre-
synaptic membrane
With Cocainebull Cocaine blocks re-uptake pumpsbull Dopamine remains in synaptic cleftbull More dopamine continues to be releasedbull Summative increase in post-synaptic transmission
Effects on mood bull Dopamine is involved in reward pathways
enhancing feelings of pleasurebull Longer-lasting feelings as dopamine is not re-
uptaken
Effects on behaviourbull feelings of euphoriabull increased energy and alertnessbull highly addictivebull association with depression as body reduces
production of own dopamine over timehttpisgdJellinek
httpisgdJellinek
Inhibitory drugs decrease post-synaptic transmission
Examples bull Alcohol benzodiazapines THC
What is the effect of tetrahydrocannibol (THC) Normal bull Dopamine release is moderated (inhibited) by GABA
With THCbull THC mimics cannabinoids and inhibits GABA release
by binding to cannabinoid receptorsbull GABA cannot inhibit dopamine releasebull More dopamine is released
Effects on mood bull Dopamine is involved in reward pathways
enhancing feelings of pleasurebull Not as extreme release of dopamine as with
cocaine but still higher than normal
Effects on behaviourbull intoxicationbull hungerbull memory impairmentbull potential dependency
httpoutreachmcbharvardeduanimationssynapseswf
httpthebrainmcgillcaintermediairephp
A scale of harm for drugsWhich dots represent bull tobaccobull alcoholbull heroinbull cocainebull THC cannabisbull ecstasy
Drag the red dot to point you think represents alcohol
How can drugs cause physical harm
How can drug use lead to addiction (dependency)
What factors contribute to development of addiction
ActivePrompt linkhttpactivepromptherokuappcomSQSNK or httpisgddrugscaleprompt httpactivepromptherokuappcomTYYBH
httpwwwyoutubecomwatchv=bCChf2WHNE4
This is a Creative Commons presentation It may be linked and embedded but not sold or re-hosted
Please consider a donation to charity via Biology4GoodClick here for more information about Biology4Good charity donations
IBiologyStephen
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
-
Decision-making in the Central Nervous System (CNS)
axon
synapse
axon hillock
actio
n po
tenti
al
Diagram adapted from httphscuweacuksynapses_neurosummationhtm
The axons of many pre-synaptic neurons feed into the dendrites of one post-synaptic
neurons via synapses
The lsquodecisionrsquo whether or not to propagate the action potential along the axon of the
post-synaptic neuron takes place in a region of the cell body
called the axon hillock
This is achieved through summationof the incoming impulses If the total
impulse reaches thresholdthe post-synaptic neuron depolarises and
the action potential is propagated
If the sum does not reach threshold the AP is not propagated
There are two main methods of summation
temporal and spatial
Decision-making in the Central Nervous System (CNS)
Diagram adapted from httphscuweacuksynapses_neurosummationhtm
Test out temporal and spatial summation Temporal summationbull Action potentials arrive in rapid
successionbull Depolarisation in the axon hillock is
summativebull If it reaches threshold before
repolarisation the AP is propagated
Spatial summationbull Action potentials arrive simultaneously
from multiple sourcesbull Some neurotransmitters are excitatory
(increasing depolarisation)bull Other NTs are inhibitory
(hyperpolarising) bull Summation in the axon hillock is
summative bull If it reaches threshold the AP is
propagated
httpwwwjellinekeubrainindexhtmlKeepThis=trueampTB_iframe=trueampheight=588ampwidth=672
How do psychoactive drugs affect the brain
Work through the excellent animations and explanations from httpwwwjellinekeu
Before thinking about how drugs affect the synapses be sure you understand how they work and are reset bull Some NTs have a normal excitatory functionbull Other NTs have a normal inhibitory function
In general psychoactive drugs can 1 Increase or decrease the release of NTs (eg
THC ndash cannabis)2 Breakdown re-uptake proteins which are
responsible for returned used components of NTs to the pre-synaptic neuron (ready to use again)
3 Block re-uptake proteins (egcocaine)4 Mimic or block NTs binding to the receptors
on post-synaptic membranes5 Inhibit production of new NTs
Excitatory drugs increase post-synaptic transmission
Examples bull Nicotine amphetamines cocaine
What is the effect of cocaine Normal bull Dopamine acts as excitatory NTbull Dopamine is re-uptaken by pumps on the pre-
synaptic membrane
With Cocainebull Cocaine blocks re-uptake pumpsbull Dopamine remains in synaptic cleftbull More dopamine continues to be releasedbull Summative increase in post-synaptic transmission
Effects on mood bull Dopamine is involved in reward pathways
enhancing feelings of pleasurebull Longer-lasting feelings as dopamine is not re-
uptaken
Effects on behaviourbull feelings of euphoriabull increased energy and alertnessbull highly addictivebull association with depression as body reduces
production of own dopamine over timehttpisgdJellinek
httpisgdJellinek
Inhibitory drugs decrease post-synaptic transmission
Examples bull Alcohol benzodiazapines THC
What is the effect of tetrahydrocannibol (THC) Normal bull Dopamine release is moderated (inhibited) by GABA
With THCbull THC mimics cannabinoids and inhibits GABA release
by binding to cannabinoid receptorsbull GABA cannot inhibit dopamine releasebull More dopamine is released
Effects on mood bull Dopamine is involved in reward pathways
enhancing feelings of pleasurebull Not as extreme release of dopamine as with
cocaine but still higher than normal
Effects on behaviourbull intoxicationbull hungerbull memory impairmentbull potential dependency
httpoutreachmcbharvardeduanimationssynapseswf
httpthebrainmcgillcaintermediairephp
A scale of harm for drugsWhich dots represent bull tobaccobull alcoholbull heroinbull cocainebull THC cannabisbull ecstasy
Drag the red dot to point you think represents alcohol
How can drugs cause physical harm
How can drug use lead to addiction (dependency)
What factors contribute to development of addiction
ActivePrompt linkhttpactivepromptherokuappcomSQSNK or httpisgddrugscaleprompt httpactivepromptherokuappcomTYYBH
httpwwwyoutubecomwatchv=bCChf2WHNE4
This is a Creative Commons presentation It may be linked and embedded but not sold or re-hosted
Please consider a donation to charity via Biology4GoodClick here for more information about Biology4Good charity donations
IBiologyStephen
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
- Slide 16
- Slide 17
- Slide 18
- Slide 19
- Slide 20
-
Decision-making in the Central Nervous System (CNS)
Diagram adapted from httphscuweacuksynapses_neurosummationhtm
Test out temporal and spatial summation Temporal summationbull Action potentials arrive in rapid
successionbull Depolarisation in the axon hillock is
summativebull If it reaches threshold before
repolarisation the AP is propagated
Spatial summationbull Action potentials arrive simultaneously
from multiple sourcesbull Some neurotransmitters are excitatory
(increasing depolarisation)bull Other NTs are inhibitory
(hyperpolarising) bull Summation in the axon hillock is
summative bull If it reaches threshold the AP is
propagated
httpwwwjellinekeubrainindexhtmlKeepThis=trueampTB_iframe=trueampheight=588ampwidth=672
How do psychoactive drugs affect the brain
Work through the excellent animations and explanations from httpwwwjellinekeu
Before thinking about how drugs affect the synapses be sure you understand how they work and are reset bull Some NTs have a normal excitatory functionbull Other NTs have a normal inhibitory function
In general psychoactive drugs can 1 Increase or decrease the release of NTs (eg
THC ndash cannabis)2 Breakdown re-uptake proteins which are
responsible for returned used components of NTs to the pre-synaptic neuron (ready to use again)
3 Block re-uptake proteins (egcocaine)4 Mimic or block NTs binding to the receptors
on post-synaptic membranes5 Inhibit production of new NTs
Excitatory drugs increase post-synaptic transmission
Examples bull Nicotine amphetamines cocaine
What is the effect of cocaine Normal bull Dopamine acts as excitatory NTbull Dopamine is re-uptaken by pumps on the pre-
synaptic membrane
With Cocainebull Cocaine blocks re-uptake pumpsbull Dopamine remains in synaptic cleftbull More dopamine continues to be releasedbull Summative increase in post-synaptic transmission
Effects on mood bull Dopamine is involved in reward pathways
enhancing feelings of pleasurebull Longer-lasting feelings as dopamine is not re-
uptaken
Effects on behaviourbull feelings of euphoriabull increased energy and alertnessbull highly addictivebull association with depression as body reduces
production of own dopamine over timehttpisgdJellinek
httpisgdJellinek
Inhibitory drugs decrease post-synaptic transmission
Examples bull Alcohol benzodiazapines THC
What is the effect of tetrahydrocannibol (THC) Normal bull Dopamine release is moderated (inhibited) by GABA
With THCbull THC mimics cannabinoids and inhibits GABA release
by binding to cannabinoid receptorsbull GABA cannot inhibit dopamine releasebull More dopamine is released
Effects on mood bull Dopamine is involved in reward pathways
enhancing feelings of pleasurebull Not as extreme release of dopamine as with
cocaine but still higher than normal
Effects on behaviourbull intoxicationbull hungerbull memory impairmentbull potential dependency
httpoutreachmcbharvardeduanimationssynapseswf
httpthebrainmcgillcaintermediairephp
A scale of harm for drugsWhich dots represent bull tobaccobull alcoholbull heroinbull cocainebull THC cannabisbull ecstasy
Drag the red dot to point you think represents alcohol
How can drugs cause physical harm
How can drug use lead to addiction (dependency)
What factors contribute to development of addiction
ActivePrompt linkhttpactivepromptherokuappcomSQSNK or httpisgddrugscaleprompt httpactivepromptherokuappcomTYYBH
httpwwwyoutubecomwatchv=bCChf2WHNE4
This is a Creative Commons presentation It may be linked and embedded but not sold or re-hosted
Please consider a donation to charity via Biology4GoodClick here for more information about Biology4Good charity donations
IBiologyStephen
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httpwwwjellinekeubrainindexhtmlKeepThis=trueampTB_iframe=trueampheight=588ampwidth=672
How do psychoactive drugs affect the brain
Work through the excellent animations and explanations from httpwwwjellinekeu
Before thinking about how drugs affect the synapses be sure you understand how they work and are reset bull Some NTs have a normal excitatory functionbull Other NTs have a normal inhibitory function
In general psychoactive drugs can 1 Increase or decrease the release of NTs (eg
THC ndash cannabis)2 Breakdown re-uptake proteins which are
responsible for returned used components of NTs to the pre-synaptic neuron (ready to use again)
3 Block re-uptake proteins (egcocaine)4 Mimic or block NTs binding to the receptors
on post-synaptic membranes5 Inhibit production of new NTs
Excitatory drugs increase post-synaptic transmission
Examples bull Nicotine amphetamines cocaine
What is the effect of cocaine Normal bull Dopamine acts as excitatory NTbull Dopamine is re-uptaken by pumps on the pre-
synaptic membrane
With Cocainebull Cocaine blocks re-uptake pumpsbull Dopamine remains in synaptic cleftbull More dopamine continues to be releasedbull Summative increase in post-synaptic transmission
Effects on mood bull Dopamine is involved in reward pathways
enhancing feelings of pleasurebull Longer-lasting feelings as dopamine is not re-
uptaken
Effects on behaviourbull feelings of euphoriabull increased energy and alertnessbull highly addictivebull association with depression as body reduces
production of own dopamine over timehttpisgdJellinek
httpisgdJellinek
Inhibitory drugs decrease post-synaptic transmission
Examples bull Alcohol benzodiazapines THC
What is the effect of tetrahydrocannibol (THC) Normal bull Dopamine release is moderated (inhibited) by GABA
With THCbull THC mimics cannabinoids and inhibits GABA release
by binding to cannabinoid receptorsbull GABA cannot inhibit dopamine releasebull More dopamine is released
Effects on mood bull Dopamine is involved in reward pathways
enhancing feelings of pleasurebull Not as extreme release of dopamine as with
cocaine but still higher than normal
Effects on behaviourbull intoxicationbull hungerbull memory impairmentbull potential dependency
httpoutreachmcbharvardeduanimationssynapseswf
httpthebrainmcgillcaintermediairephp
A scale of harm for drugsWhich dots represent bull tobaccobull alcoholbull heroinbull cocainebull THC cannabisbull ecstasy
Drag the red dot to point you think represents alcohol
How can drugs cause physical harm
How can drug use lead to addiction (dependency)
What factors contribute to development of addiction
ActivePrompt linkhttpactivepromptherokuappcomSQSNK or httpisgddrugscaleprompt httpactivepromptherokuappcomTYYBH
httpwwwyoutubecomwatchv=bCChf2WHNE4
This is a Creative Commons presentation It may be linked and embedded but not sold or re-hosted
Please consider a donation to charity via Biology4GoodClick here for more information about Biology4Good charity donations
IBiologyStephen
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Excitatory drugs increase post-synaptic transmission
Examples bull Nicotine amphetamines cocaine
What is the effect of cocaine Normal bull Dopamine acts as excitatory NTbull Dopamine is re-uptaken by pumps on the pre-
synaptic membrane
With Cocainebull Cocaine blocks re-uptake pumpsbull Dopamine remains in synaptic cleftbull More dopamine continues to be releasedbull Summative increase in post-synaptic transmission
Effects on mood bull Dopamine is involved in reward pathways
enhancing feelings of pleasurebull Longer-lasting feelings as dopamine is not re-
uptaken
Effects on behaviourbull feelings of euphoriabull increased energy and alertnessbull highly addictivebull association with depression as body reduces
production of own dopamine over timehttpisgdJellinek
httpisgdJellinek
Inhibitory drugs decrease post-synaptic transmission
Examples bull Alcohol benzodiazapines THC
What is the effect of tetrahydrocannibol (THC) Normal bull Dopamine release is moderated (inhibited) by GABA
With THCbull THC mimics cannabinoids and inhibits GABA release
by binding to cannabinoid receptorsbull GABA cannot inhibit dopamine releasebull More dopamine is released
Effects on mood bull Dopamine is involved in reward pathways
enhancing feelings of pleasurebull Not as extreme release of dopamine as with
cocaine but still higher than normal
Effects on behaviourbull intoxicationbull hungerbull memory impairmentbull potential dependency
httpoutreachmcbharvardeduanimationssynapseswf
httpthebrainmcgillcaintermediairephp
A scale of harm for drugsWhich dots represent bull tobaccobull alcoholbull heroinbull cocainebull THC cannabisbull ecstasy
Drag the red dot to point you think represents alcohol
How can drugs cause physical harm
How can drug use lead to addiction (dependency)
What factors contribute to development of addiction
ActivePrompt linkhttpactivepromptherokuappcomSQSNK or httpisgddrugscaleprompt httpactivepromptherokuappcomTYYBH
httpwwwyoutubecomwatchv=bCChf2WHNE4
This is a Creative Commons presentation It may be linked and embedded but not sold or re-hosted
Please consider a donation to charity via Biology4GoodClick here for more information about Biology4Good charity donations
IBiologyStephen
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httpisgdJellinek
Inhibitory drugs decrease post-synaptic transmission
Examples bull Alcohol benzodiazapines THC
What is the effect of tetrahydrocannibol (THC) Normal bull Dopamine release is moderated (inhibited) by GABA
With THCbull THC mimics cannabinoids and inhibits GABA release
by binding to cannabinoid receptorsbull GABA cannot inhibit dopamine releasebull More dopamine is released
Effects on mood bull Dopamine is involved in reward pathways
enhancing feelings of pleasurebull Not as extreme release of dopamine as with
cocaine but still higher than normal
Effects on behaviourbull intoxicationbull hungerbull memory impairmentbull potential dependency
httpoutreachmcbharvardeduanimationssynapseswf
httpthebrainmcgillcaintermediairephp
A scale of harm for drugsWhich dots represent bull tobaccobull alcoholbull heroinbull cocainebull THC cannabisbull ecstasy
Drag the red dot to point you think represents alcohol
How can drugs cause physical harm
How can drug use lead to addiction (dependency)
What factors contribute to development of addiction
ActivePrompt linkhttpactivepromptherokuappcomSQSNK or httpisgddrugscaleprompt httpactivepromptherokuappcomTYYBH
httpwwwyoutubecomwatchv=bCChf2WHNE4
This is a Creative Commons presentation It may be linked and embedded but not sold or re-hosted
Please consider a donation to charity via Biology4GoodClick here for more information about Biology4Good charity donations
IBiologyStephen
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httpoutreachmcbharvardeduanimationssynapseswf
httpthebrainmcgillcaintermediairephp
A scale of harm for drugsWhich dots represent bull tobaccobull alcoholbull heroinbull cocainebull THC cannabisbull ecstasy
Drag the red dot to point you think represents alcohol
How can drugs cause physical harm
How can drug use lead to addiction (dependency)
What factors contribute to development of addiction
ActivePrompt linkhttpactivepromptherokuappcomSQSNK or httpisgddrugscaleprompt httpactivepromptherokuappcomTYYBH
httpwwwyoutubecomwatchv=bCChf2WHNE4
This is a Creative Commons presentation It may be linked and embedded but not sold or re-hosted
Please consider a donation to charity via Biology4GoodClick here for more information about Biology4Good charity donations
IBiologyStephen
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A scale of harm for drugsWhich dots represent bull tobaccobull alcoholbull heroinbull cocainebull THC cannabisbull ecstasy
Drag the red dot to point you think represents alcohol
How can drugs cause physical harm
How can drug use lead to addiction (dependency)
What factors contribute to development of addiction
ActivePrompt linkhttpactivepromptherokuappcomSQSNK or httpisgddrugscaleprompt httpactivepromptherokuappcomTYYBH
httpwwwyoutubecomwatchv=bCChf2WHNE4
This is a Creative Commons presentation It may be linked and embedded but not sold or re-hosted
Please consider a donation to charity via Biology4GoodClick here for more information about Biology4Good charity donations
IBiologyStephen
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httpwwwyoutubecomwatchv=bCChf2WHNE4
This is a Creative Commons presentation It may be linked and embedded but not sold or re-hosted
Please consider a donation to charity via Biology4GoodClick here for more information about Biology4Good charity donations
IBiologyStephen
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IBiologyStephen
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