1. By the end of this section you will be able to …..
State the role of endorphins
State 4 ways endorphin levels in the body can be increased
State 3 effects increased levels of endorphins can have on the body
State what is meant by the reward pathway
Describe dopamine’s role in the reward pathway.
Name 2 neurotransmitter related disorders
Describe how agonists, antagonists and other drugs (inhibitors) work when treating neurotransmitter related disorders
The functions of endorphins and dopamine.
Endorphins are neurotransmitters that stimulate neurones involved in reducing the intensity of pain. Increased levels are also connected with euphoric feelings, appetite modulation and release of sex hormones. Endorphin production increases in response to severe injury, prolonged and continuous exercise, stress and certain foods.
Dopamine induces the feeling of pleasure and reinforces particular behaviour in the reward pathway.
Neurotransmitter related disorders and their treatment.
Agonists bind to and stimulate receptors mimicking the neurotransmitter. Antagonists bind to specific receptors blocking the action of the neurotransmitter. Other drugs inhibit the enzymes which degrade neurotransmitters or inhibit re-uptake.
The reward pathway involves neurones which secrete or respond to the neurotransmitter dopamine. The reward pathway is activated on engagement of beneficial behaviours, eg eating when hungry.
Many drugs used to treat neurotransmitter related disorders are similar to neurotransmitters

2. Neurotransmitters!

3. Neurotransmitters, Mood and Behaviour.
Some neurotransmitters play a big part in how we feel and how we behave.
Two examples of such neurotransmitters are:
Endorphins
Dopamine

4. Endorphins

5. Endorphins
Endorphins are neurotransmitters that stimulate neurones involved in reducing the intensity of pain.
They act as natural pain killers by combining with receptors at synapses and blocking the transmission of pain signals.

6. When are additional endorphins released?
Endorphins in chocolate can reduce stress and improve mood.
Chocolate also contains theobromine, phenylalanine and caffeine which can increase awareness and concentrations levels as well as feeling of comfort and happiness 

7. Increased Levels of Endorphins
An increase in endorphin levels can be brought about by:
Severe injury
Prolonged/continuous exercise
Stress
And certain foods e.g. chocolate
Endorphins are produced in the hypothalamus and increased levels in the body can cause:
Euphoric feelings
Appetite modulation (regulation)
The release of sex hormones

8. Dopamine
Dopamine is a neurotransmitter produced in several regions of the brain.
Two of these areas are located in the limbic system.
It has a key role in activating the brains ‘reward pathway’ and in the control and coordination of movement.
Limbic System
Limbic diagram

9. What is the Reward Pathway?

10. What is the Reward Pathway?
The reward pathway involves neurons which secrete or respond to the neurotransmitter dopamine.
The reward pathway is activated on engagement of beneficial behaviours e.g. eating when hungry:
Area ‘V’ releases dopamine
This travels to area ‘N’ which also produces dopamine inducing a pleasurable feeling.
Dopamine induces pleasure and reinforces particular behaviour in the reward pathway

11. Neurotransmitter related disorders and their treatment
Form of dementia that is incurable.
Caused by a progressive loss of neurones which produce acetylcholine.
Drugs which inhibit the enzyme which removes acetylcholine from the synaptic cleft have improved symptoms but have ultimately been ineffective.
Alzheimer's

12. Neurotransmitter related disorders and their treatment
Caused by the loss of dopamine synthesising neurones.
Loss of dopamine can affect control and coordination of movement.
Dopamine cannot be given as a treatment as it cannot cross the blood brain barrier.
Patients are given drugs such as L-dopa but they have unpleasant side effects.
Research into the use of stem cells to treat PD is currently underway.
Parkinson's

13. Treatment of neurotransmitter related disorders
Many drugs used to treat neurotransmitter related disorders are similar to neurotransmitters.
Agonists
Antagonists
Other drugs (Inhibitors)
Agonists bind to and stimulate receptors mimicking the neurotransmitter. e.g. L-dopa in Parkinson's
Antagonists bind
to specific
receptors blocking
the action of the
neurotransmitter.
e.g. Beta –blockers for anxiety
Inhibitors inhibit the enzyme involved in degradation or re-uptake of the neurotransmitter. e.g. Cholinesterase inhibitors for Alzheimer's
Fig 18.3 pg266
Agonist enhance activity

14. Agonists
Antagonists

15. By the end of this section you will be able to …..
State the role of endorphins
State 4 ways endorphin levels in the body can be increased
State 3 effects increased levels of endorphins can have on the body
State what is meant by the reward pathway
Describe dopamine’s role in the reward pathway.
Name 2 neurotransmitter related disorders
Describe how agonists, antagonists and other drugs (inhibitors) work when treating neurotransmitter related disorders
The functions of endorphins and dopamine.
Endorphins are neurotransmitters that stimulate neurones involved in reducing the intensity of pain. Increased levels are also connected with euphoric feelings, appetite modulation and release of sex hormones. Endorphin production increases in response to severe injury, prolonged and continuous exercise, stress and certain foods.
Dopamine induces the feeling of pleasure and reinforces particular behaviour in the reward pathway.
Neurotransmitter related disorders and their treatment.
Agonists bind to and stimulate receptors mimicking the neurotransmitter. Antagonists bind to specific receptors blocking the action of the neurotransmitter. Other drugs inhibit the enzymes which degrade neurotransmitters or inhibit re-uptake.
The reward pathway involves neurones which secrete or respond to the neurotransmitter dopamine. The reward pathway is activated on engagement of beneficial behaviours, eg eating when hungry.
Many drugs used to treat neurotransmitter related disorders are similar to neurotransmitters