Week 4 - ADHD

Question 1

Which regions of the brain are implicated in ADHD?

Answer 1

Nucleus Accumbens, Striatum, and Prefrontal Cortex

Question 2

Which neurotransmitters are involved in ADHD?

Answer 2

Dopamine and Noradrenaline

Question 3

Which receptor families are associated with noradrenaline in ADHD?

Answer 3

Alpha and Beta receptors

Question 4

What receptor families are activated by dopamine?

Answer 4

D1 and D2 receptor families

Question 5

What happens to neurotransmitter release in individuals with ADHD?

Answer 5

For every action potential, there is less neurotransmitter released because there are lower levels of dopamine and noradrenaline. This leads the neurons firing at a higher frequency which results in an erratic noisy signal. Hence the ability of the brain to communicate effectively is decreased because of this noisiness and hence the symptoms of inattention etc.

Question 6

What neurotransmitters are typically implicated in individuals with ADHD? and how so?

Answer 6

Lower levels of dopamine and noradrenaline

Question 7

What is the primary objective of treatments for ADHD?

Answer 7

Treatment for ADHD aims to reduce neural “noise” and high firing frequency by enhancing the amount of and the duration of dopamine or noradrenaline in the synaptic cleft.

• As a result the PFC has what it needs so the firing rate is decreased and the signal is clarified

Question 8

What is the mechanism of action for reuptake (transporter) antagonists?

Answer 8

Reuptake (transporter) antagonists bind to neurotransmitter transporters, preventing their normal function and increasing the concentration of neurotransmitters in the synaptic cleft

Question 9

Which categories of drugs are commonly used in the treatment of ADHD?

Answer 9

Antagonists, Blockers and Reversers

1. Reuptake (Transporter) Antagonists
2. Reuptake (Transporter) Blockers
3. Reuptake (Transporter) Reversers

Question 10

What is the mechanism of action for reuptake (transporter) blockers?

Answer 10

Reuptake (transporter) blockers bind to neurotransmitter transporters, inhibiting their ability to reabsorb neurotransmitters from the synaptic cleft. This leads to increased concentrations of neurotransmitters in the synaptic space

Question 11

What is the mechanism of action for reuptake (transporter) reversers?

Answer 11

Reuptake (transporter) reversers bind to neurotransmitter transporters and induce their reversal, causing neurotransmitters to flow out of the neuron and into the synaptic cleft instead of being reabsorbed.

Question 12

List some reuptake (transporter) antagonists used in ADHD treatment?

Answer 12

• Methylphenidate (e.g. Ritalin)
• Atomoxetine (Strattera)
• Dexamphetamine (e.g. Vyvanse)

Question 13

List some reuptake (transporter) blockers used in ADHD treatment?

Answer 13

• Methylphenidate (e.g. Ritalin and concerta)
• Extended-release methylphenidate (e.g. Ritalin LA)
• OROS methylphenidate (e.g. Concerta)

Question 14

List some reuptake (transporter) reversers used in ADHD treatment?

Answer 14

Dexamphetamine, Lisdexamphetamine (Aspen, Vyvanse)

Question 15

What are Antipsychotics (such as Quetiapine (Seroquel) and Risperidone (Risperdal)) used for in ADHD?

Answer 15

Antipsychotics can be used at low doses to offset side effects of reuptake blockers, or to reduce aggression and anger in individuals with ADHD.

Question 16

Other drugs used in ADHD?

Answer 16

alpha 2 (A2) receptor agonist –> activates NA neurons of LC, (increasing NA release in
PFC) and directly acts on A2 receptors in PFC (postsynaptic on pyramidal
neurons)

Can be used as adjunct therapy, or second line treatment to help regulate attention and behaviour

Question 17

What are Catecholamines?

Answer 17

They are a class of neurotransmitters. The main catecholamines involved in signalling are dopamine and noradrenaline (and epinephrine).