Week 8

Question 1

Glutamate

Answer 1

– ThedominantexcitatoryCNSneurotransmitter
– Binds/opensiGluRs(ionotropicglutamatereceptors)
• AMPA receptor is a Na+ channel (EPSP)
• NMDA receptor is a Na+ and Ca2+ channel (EPSP)
– AlsomGluRs(metabotropicglutamatereceptors)

Question 2

GABA

Answer 2

– ThedominantinhibitoryCNSneurotransmitter
– Binds/opens GABAARs: Cl- channels
• Cl- influx causing hyperpolarisation
• Inhibits post-synaptic neuron (IPSP)
– AlsoGABABRs(metabotropic)

Question 3

Acetylcholine (ACh) - excitatory or inhibitory

Answer 3

– Nicotinic (nAChR)
• Ionotropic - ligand-gated Na+ channel • Always excitatory
– Muscarinic (mAChR) - GPCRs
• Metabotropic - activates enzymes • Often inhibitory (can be excitatory)

Question 4

Nordrenaline (NA) - excitatory or inhibitory

Answer 4

– Alpha-adrenergic receptors - GPCRs
• Metabotropic - activates enzymes • Excitatory of inhibitory
– Beta-adrenergic receptors - GPCRs
• Metabotropic - activates enzymes
• Excitatory or inhibitory

Question 5

Normal cognition

Answer 5

• ‘Normal’ thinking depends on the balance of excitatory Glutamate & inhibitory GABA → = impaired cognition
• Behaviour and emotions are even more complicated

Question 6

Dopamine (DA) - ON

Answer 6

• ON = activate DA Receptors (GPCRs)
– D1-like (↑cAMP) and D2-like (↓cAMP) are all GPCRs but act in contradictory ways

Question 7

Dopamine (DA) - OFF

Answer 7

– Reuptake - DA transporter (DAT), then…
– broken down by enzymes: monoamine oxidase (MAO), catechol-O-methyl transferase (COMT)

Question 8

Serotonin or 5-hydroxytriptamine (5-HT) - ON

Answer 8

• ON = activate 5-HT Receptors
– The 5-HT receptors, are GPCRs → signalling
• (except 5-HT3 receptor = ligand-gated cation channel)

Question 9

Serotonin or 5-hydroxytriptamine - OFF

Answer 9

• OFF = reuptake
– monoamine transporter (SERT), on the presynaptic neuron.
– Various agents can inhibit 5-HT reuptake, including cocaine, tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs) → increase synaptic 5-HT