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According to the Specification you
need to be able to :
Describe, with reference to heroin and nicotine
1. Mode of action
2. Effects
3. Tolerance
4. Physical / psychological dependencies
5. withdrawal
You can think of a brain pathway as a power line that connects two brain
regions. Brain pathways are made up of interconnected neurons along which
signals are transmitted from one brain region to another.
Dopamine is the neurotransmitter used by the reward pathway. But there are
other important pathways in the brain that utilize dopamine.
Generally, drugs that affect dopamine levels in the brain affect all of these
dopamine pathways.
http://www.youtube.com/watch?v=Tl8-C9ZuLTA
Dopamine and another neurotransmitter called Serotonin are released
by a small number of neurons in the brain.
Nigrostriatal pathway
Substantia Nigra to
Striatum
. Motor control
. Death of neurons in
this pathway can result
in
Parkinson's Disease
Mesolimbic and Mesocortical
pathways
Ventral Tegmental Area to Nucleus
Accumbens, Amygdala & Hippocampus,
and Prefrontal Cortex
. Memory
. Motivation and emotional response
. Reward and desire
. Addiction
. Can cause hallucinations and
schizophrenia if not functioning properly
There are 3 main
pathways that use
Dopamine
Tuberoinfundibular pathway
Hypothalamus to Pituitary gland
. Hormonal regulation
. Maternal behavior (nurturing)
. Pregnancy
. Sensory processes
http://learn.genetics.utah.edu/content/addiction/rewardbehavior/
Mode of Action:
http://learn.genetics.utah.edu/co
ntent/addiction/crossingdivide/
Glutamate and GABA
A system in Balance
• Glutamate and GABA (gamma-aminobutyric acid)
are the brain's major "workhorse"
neurotransmitters.
• Over half of all brain synapses release glutamate,
and 30-40% of all brain synapses release GABA.
• Since GABA is inhibitory and glutamate is excitatory,
both neurotransmitters work together to control
many processes, including the brain's overall level of
excitation.
• Many of the drugs of abuse affect either glutamate
or GABA or both to exert tranquilizing or stimulating
effects on the brain.
As an antagonist of the GABA receptor, Heroin blocks GABA binding.
This in turn elevates the quantity of Dopamine produced in this
pathway.
This causes an increase in the concentration of dopamine at the
synapse throughout the reward pathway.
Heroin blocks the inhibitor
Gaba (traffic cop) –controls the dopamine
activity in the synapse
Heroin stops it
from working
by locking it up
Mode of Action:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
In groups…..
• Use this system to explain how tolerance may occur…
•
•
•
•
Why may the first ‘high’ never be achieved?
Describe how this leads to physiological dependence?
Describe how this leads to psychological dependence?
Why is withdrawal so bad?
Heroin - Effects
• What is it like to take Heroin?
• http://www.youtube.com/watch?v=v6uBkJSbQO
0
• http://www.youtube.com/watch?v=hLVl7Asp3k
• Morphine Withdrawal :
• http://www.youtube.com/watch?v=7hw4Hvu
HnQ8&NR=1
Pete has been admitted to rehab
clinics on a regular basis over the
past 3 years. He has had drug
dependency and addiction issues for
around 5-6 years which has seriously
jeopardized his health. Pete abuses
heroin on a regular basis, mainly
injecting the substance. However, he
has failed to fully comply with any of
his doctor’s orders. This includes
complete detoxification (controlled
withdrawal from drugs) which also
involves counseling sessions.
In your groups:
List all of the Bio-psycho-social factors that may be
preventing Pete from choosing a healthy lifestyle.
Exam questions
What is meant by health Psychology? (3 Marks)
With reference to at least two areas, discuss the
work of a health psychologist. (12 marks)
HW – Next week
• Complete the two questions from last lessons
worksheet.
• Read and make notes on Heroin in textbook
• Look and Talk to Frank website
• http://www.youtube.com/watch?v=aBR2_mc6A4c
– Watch this documentary and make notes on the
Biopsychosocial effects of Bens addiction.
i.e. Biological, cognitive, social and learning
• Read and make notes on the PET ejaculation study.