Types of Neurotransmitters

Question 1

Acetylcholine

Answer 1

• The neuromuscular junction
• Also basal forebrain → wakefulness, arousal, attention, etc.
• Nicotine (also a mild psychostimulant) - that’s why nicotine acts as a mild cognitive enhance (because of the above point)

Question 2

Endocannabinoids

Answer 2

• Travel from dendrite to axon, ie. retrograde transmission → produced in the dendrite, released in the postsynaptic side, cross back to the presynaptic side and bind to receptors
• Weaken connection between two cells at a synapse
• Brain is trying to forget
• They’re so fatty in their design and can cross membranes very easily so it can’t be stored in the cell so it has to be synthesized right away

Question 3

Adenosine

Answer 3

• Remember : ATP is cellular energy
• Adenosine is an ATP by product (when broken down because ADP, then ANP, then adenosine)
• Adenosine receptors (all across the whole brain)
• Adenosine builds up in the brain throughout the day (dampening your brain and making you sleepy)
• Only one mechanism for sleep (3-4 others)
• Caffeine/theophylline → adenosine antagonist (block the effects of adenosine), body tries to add more receptors to compensate so over time coffee won’t make a difference

Question 4

Endogenous Opioids

Answer 4

• Aka. Endorphins
• Giant peptide neurotransmitters
• The neurotransmitter system that exogenous opioids (eg.heroin) mimic
  Fentanyl and naloxone (naloxone blocks pleasure)
• Receptors are all GPCRs
• Receptors found in spinal cord, periaqueductal grey (PAG), nucleus accumbens, more

Question 5

Norepinephrine

Answer 5

Originates in brain stem region called the locus coeruleus
Enhancement of memory by stress/emotion
Potential PTSD treatment via reconsolidation?
More likely to see synaptic changes when norepinephrine is involved (tells the brain that the event is important when stressed)
Propranolol - for mediating heart rate, norepinephrine antagonist (blocking some of the effects of stress effects)
Consolidation → when transfer something from working memory to long term memory
Reconsolidation → Every time you remember an event it’s subject to distortment and then it’s laid down again
So using propranolol (beta blocker) during reconsolidation can potentially treat PTSD

Question 6

Serotonin

Answer 6

Primarily produced by the raphe nuclei (brain stem)
Precursore: tryptophan
Can’t get tryptophan to the brain without carbs
Serotonin depletion studies
- Very costly
- Have participants live at the lab for a number of days
- Experimental group eats a tryptophan depleted diet
- Serotonin levels deplete from low tryptophan
– Decrease in cognitive flexibility
– Increased levels of aggression and impulsivity
– Usually don’t see decreased levels of mood (unless if person has a family history of depressive disorders)

Question 7

Selective Serotonin Reuptake Inhibitors

Answer 7

For depression
Block serotonin from being removed from the synapse
Effect of SSRIs are quick, improvements are slow
SSRI Efficacy
Meta-analyses: SSRIs no better than placebo for mild to moderate depression
May help with major depression but the effect size is tiny → causing little benefit