Neurotransmitters CNS - Trachte

Question 1

What is the sequence of events in a synapse?

Answer 1

Presynaptic membrane depolarization
Ca channels activate and let Ca into presynaptic neuron
Ca entry promtores NT vesicles docking with plasma membrane
NT diffuses across synapse
NT binds to receptor and changes membrane pot.
Excitation causes EPSP, inhibition causes IPSP

Question 2

Contrast ligand-gated (ionotropic) with metabotropic receptors:

Answer 2

Ligand-gated channels

• Open briefly (tens of milliseconds)
• Account for fast action potentials
• An example is glutamate receptors

Metabatropic receptors

• Receptor interacts with a GTP-binding protein
• Modulates voltage gated channels
• Typically enhances K or inhibits Ca channels
• Typically inhibitory

Question 3

Give an example of a drug you can give to a patient that they can then synthesize into a necessary neurotransmitter:

Answer 3

L-DOPA given to increase amounts of dopamine

Question 4

What is Cocaine’s mechanism of action?

Answer 4

prevents dopamine uptake into nerves

Question 5

What NTs are associated with hierarchal pathways?

Answer 5

Glutamate, GABA, glycine

Question 6

What extra do NMDA receptors need to work, apart from Glutamate?

Answer 6

A depolarizeed membrane potential.

Question 7

What are the differences between D1 and D2 dopamine receptors?

Answer 7

d1

• Gs protein coupled to cAMP production
• Associated with Tourrette’s

d2

• Gi protein coupled to inhibit cAMP
• substantia nigra and neostriatum projections
• suppress GABA release
• ANtiscychotics antagonize these receptors

Question 8

Summary of disease associations:

Answer 8

Motor stimulation
-Glutamate

Motor inhibition

• GABA
• Glycine
• Norepinephrine

Motor stimulation via inhibition of inhibition
-Dopamine

Memory
-Acetylcholine

Psychoses

• Dopamine D2 receptor
• 5 Hydroxytryptamine
• 5 HT2 receptors

Pain
-Opioids

Question 9

Summary of NT’s

Answer 9

Glutamate- major stimulatory neurotransmitter
GABA- major inhibitory neurotransmitter
Glycine- inhibitory neurotransmitter
Acetylcholine- inhibitory via muscarinic and stimulatory via nicotinic receptors; involved with memory
Dopamine- inhibitory neurotransmitter on other inhibitory neurotransmitters (disinhibition); movement & psychoses
Norepinephrine- inhibitory neurotransmitter via alpha2 receptor
Serotonin-inhibitory neurotransmitter via 5HT2; psychoses
Opioids- inhibitory neurotransmitter
Be aware of potential relevance of each for motor function, cognition, memory and psychoses