Chemical Imbalance

Question 1

What is Parkinson’s disease + symptoms?

Answer 1

Brain disorder affecting coordination of movement caused by loss of neurones, results in symptoms:
- tremors, slow movement, difficulty w balance, stiff muscles

Question 2

What is Parkinson’s caused by ?

Answer 2

• Insufficient amount of dopamine due to loss of DA-producing neurones
• Less dopamine binds with receptors on post synaptic membrane, fewer Na channels opened so less action potential is generated —> leads to symptoms of tremor/slow movement

Question 3

How can Parkinson’s disease be treated?

Answer 3

L-dopa
~ dopamine precursor
~ able to cross blood-brain barrier + converted into dopamine by enzyme dopa-decarboxylase
Enzyme inhibitors
~ inhibit activity of enzymes that would normally break down dopamine in the synaptic cleft, raising levels of dopamine e.g MAOB
Dopamine agonists
Produce the same effect as dopamine by binding to and activating the dopamine receptors on the postsynaptic membrane

Question 4

What is depression linked to?

Answer 4

Low levels of the neurotransmitter serotonin —> transmits nerve impulses through the areas of the brain that control mood

Question 5

Describe treatments for depression

Answer 5

SSRIs
selective serotonin reuptake inhibitors —> type of antidepressant that prevent the uptake of serotonin at synapses; increases overall levels of serotonin in the brain

Question 6

Why can dopamine not be given directly to Parkinson’s patients?

Answer 6

Because dopamine cannot pass the blood-brain barrier

Question 7

What is the effect of MDMA on neurotransmitters?

Answer 7

MDMA (ecstasy)
- serotonin usually reabsorbed into presynaptic neurone
- inhibits reuptake of serotonin by binding to specific proteins enabling reuptake on presynaptic membrane
- increases amount of serotonin present in brain