3- Neurotransmitter Theories of Schizophrenia

Question 1

What does the dopamine hypothesis explain?

Answer 1

Positive symptoms

Question 2

How does the dopamine hypothesis explain schizophrenia?

Answer 2

Caused by synapse overactivity between dopaminergic neurons of ventral tegmental area and neurons in mesolimbic pathway (nucleus accumbens and amygdala)

Question 3

What are dopaminergic neuron activity involved in in these areas?

Answer 3

Reinforcement

Question 4

What do agonists on dopaminergic neuron synapses do?

Answer 4

Reinforce behaviour

Question 5

What happens when dopamine agonists are taken in large doses?

Answer 5

They induce positive psychosis symptoms and worsen symptoms in schizophrenia patients

Question 6

What do antagonists on dopaminergic neuron synapses do?

Answer 6

Work as antipsychotic medication

Question 7

What 2 effects are produced by dopamine antagonists?

Answer 7

1. Reduce positive symptoms
2. Side effects caused Parkinson’s-like symptoms

Question 8

Link to schizophrenia with DA agonist drugs?

Answer 8

Induces/worsens psychotic symptoms

Question 9

Link to schizophrenia with DA receptor antagonists?

Answer 9

Reduce symptoms

Question 10

Link to schizophrenia with DA depleting drugs?

Answer 10

Reduce symptoms

Question 11

Link to schizophrenia with DA metabolites in CSF and plasma?

Answer 11

Increased in schizophrenia

Question 12

Link to schizophrenia with DA metabolite levels in the brain?

Answer 12

DA increased in striatum

Question 13

Link to schizophrenia with DA synthesis?

Answer 13

DA increased in striatum

Question 14

What is the suggestion about the control of striatal dopaminergic activity in schizophrenia?

Answer 14

Too much dopamine activity in the striatum

Question 15

What is increased dopamine activity associated with?

Answer 15

Schizophrenia positive symptoms

Question 16

What is the most abundant neurotransmitter in the CNS?

Answer 16

Glutamate

Question 17

What is glutamate’s effect?

Answer 17

Excitatory

Question 18

How many synaptic connections is glutamate in?

Answer 18

> 90%

Question 19

Where does glutamate have a key role?

Answer 19

In learning and memory

Question 20

What is glutamate involved in?

Answer 20

Synaptic plasticity

Question 21

What 3 classes of glutamate receptors are there?

Answer 21

1. AMPA receptors
2. NMDA receptors
3. Metabotropic glutamate receptors

Question 22

What is glutamate’s relevance to schizophrenia?

Answer 22

1. Several associated genes code for proteins related to glutamate receptors
2. Involved in pathway influencing mesolimbic dopamine activity
3. May explain cognitive and negative symptoms