Neurotransmitters

Question 1

How does reduction in ACh lead to Alzheimer’s Disease?

Answer 1

• Degeneration of cholinergic neurons -> reduction of ACh in the brain -> loss of postsynaptic neurons that respond to cholinergic neurons
• Synthetic chemicals like nerve gas can be used to help slow the progression of AD – inhibit AChE and increase [ACh] in synapses

Question 1

What is Acetylcholine?
What breaks it down?

Answer 1

• Major neurotransmitter in the brain and PNS at the NMJ
• Released by cholinergic neurons
• Destroyed by AChE (found in pre- and postsynaptic membranes)

Question 2

What are Catecholamines?
Where are they snthesized?
Where are they broken down?

Answer 2

• Dopamine, epinephrine (epi) and norepinephrine (NE)
• Synthesized in the brainstem and hypothalamus, epi and NE also synthesized in the adrenal glands
• Broken down by monoamine oxidase
• Monoamine oxidase inhibitors increase dopamine and NE
  concentration in the synapse and can be used to treat
  depression

Question 3

What is the purpose of Monoamine oxidase inhibitors?

Answer 3

• Monoamine oxidase inhibitors increase dopamine and NE
  concentration in the synapse and can be used to treat
  depression

Question 4

What is Serotonin?

Answer 4

• Serotonergic neurons innervate virtually every structure in the brain and spinal cord
• Excitatory effect on pathways involved in muscle control, inhibitory effect on pathways that mediate sensation
• Plays a role in regulation of food intake, mood and anxiety

Question 5

What are Selective serotonin reuptake inhibitors used for?

Answer 5

Selective serotonin reuptake inhibitors (SSRIs) can be used to treat depression

• Inactivates the presynaptic membrane 5-HT transporter -> mediates the reuptake of serotonin in the presynaptic cell -> increasing [serotonin] in the synaptic cleft

Question 6

Amino Acid Neurotransmitters

What is Glutamate?

Answer 6

• Most common excitatory neurotransmitter in the CNS
• High concentrations in the extracellular fluid can cause a pain response

Question 7

Amino Acid Neurotransmitters

What is GABA (gamma-aminobutyric acid)?

Answer 7

Major inhibitory neurotransmitter in the brain

• Not used to build proteins (modified form of glutamate)

Question 8

What is Benzodiazepines used for?

Answer 8

Benzodiazepines reduce anxiety, guard against seizures and induce sleep by increasing Cl- flux through the GABA receptor