Peptides, lipids, nucleotides & gasses: L20

Question 1

Non-traditional neurotransmitters (4)

Answer 1

1. peptides
2. nucleosides
3. lipids
4. gases

Question 2

non-traditional neurotransmitters do NOT satisfy all criteria for a normal neurotransmitter: (3)

Answer 2

1. present in presynaptic terminals
2. released from presynaptic terminals after neuron fires
3. existence of receptors on postsynaptic neurons

Question 3

Peptides

1. structure
2. (in contrast) proteins consist of

Answer 3

1. consist of 2 or more amino acids

2. more amino acids. either produced in body or eaten (much larger) = essential amino acids

Question 4

Peptides: synthesis & release

1. in the brain they
2. Most peptides serve as
3. good example of

Answer 4

1. are NOT synthesised from smaller compounds but the product of larger compounds (poly-peptides) being broken down into peptides within the neuron before release at the terminal button
2. modulators, however many others (hormones) also act as neurotransmitters & are co-released with other NTs
3. same compound having multiple roles & different functions in different contexts or brain regions

Question 5

Peptides - opioids

1. best known family of peptide neurotransmitters are
2. in the brain the highest density of…
   1) endogenous opioids =
   2) opiates =
3. opiate drugs known for

Answer 5

1. the endogenous opioids
2. opiate receptors are in areas involved in pain
   1) originating internally
   2) drugs like morphine, heroin
3. analgesic (pain relief) & euphoric properties

Question 6

Peptides - opiate drugs

1. heroin can
2. treatments for heroin dependancy
   1) buprenorphine
   2) naloxone
   3) methadone

Answer 6

1. cause death by respiratory failure (but not particularly neurotoxic)
2. 1) partial agonist
   2) full antagonist - rapidly block effects of heroin & prevent overdose (used by hospitals)
   3) full agonist & used in treatment of dependence because it has a much slower time course than heroin

Question 7

Lipids

1. structure
2. they are
3. main biological function (3)
4. synthesis pathways

Answer 7

1. naturally occurring molecules including fats, waxes
2. hydrophobic (water fear)
3. energy storage, signalling & provide the structural components of the cell membranes
4. unclear for many lipids that serve as neurotransmitters/modulators

Question 8

Lipids

1. best known lipid neurotransmitters
2. 2 known cannabinoid receptors
3. by regulating the activity of those neurons & release of neuromodulators these receptors..

Answer 8

1. endocannabinoids
2. 1) CB1 - found in the brain, responsible for main psychological effects. receptor activation > shortens duration of APs in presynaptic neuron > decreasing amount of neurotransmitter released
   2) CB2 - found in peripheral tissue
3. act to modulate the modulators

Question 9

Lipids - cannabis

1. active component
2. linked to
3. therapeutically used to

Answer 9

1. THC
2. apathy & underachievement
3. reduce nausea, relives asthma, decreases pressure within the eyes in glaucoma

Question 10

Medicinal cannabis

1. in 2016
2. from 2017
3. efficacy (produce desired intention) of cannabis
4. recent 2016 paper in the lancet reported a

Answer 10

1. medicinal cannabis act passed in victoria
2. children with severe intractable epilepsy will access cannabis
3. in the treatment of epilepsy compared to approved therapies is unknown
4. large open label study -> cannabis seizure reduction = similar to existing drugs

Question 11

Nucleosides

1. structure
2. synthesis
3. “co-transmitters” -> serve to modulate the release of other transmitters…

Answer 11

1. subunit of nucleic acids (heredity controlling components of all living cells, e.g. DNA & RNA)
2. obtained by chemical/enzymatic breakdown of nucleic acids
3. modulating the modulators

Question 12

Nucleosides - Adenosine

1. adenosine in the brain is a ..
2. it is a nucleoside that forms from
3. when you are awake adenosine levels
4. at synapses where adenosine is the primary neurotransmitter, a high postsynaptic firing rate =

Answer 12

1. inhibitory neurotransmitter
2. the breakdown of adenosine triphosphate (ATP) = primary energy source in cells for transport systems & many enzymes
3. gradually rise & promotes sleep, suppressing arousal
4. leads to sleepiness

Question 13

Nucleosides - caffeine

1. for plants
2. how many cups consumed a year

Answer 13

1. caffeine = natural pesticide, paralyses & kills insects
2. 400 billion

Question 14

Nucleosides - caffeine

1. acts as a
2. caffeine increases alertness by

Answer 14

1 adenosine-receptor antagonist & blocks the natural action of adenosine
2. reducing the firing/activation of adenosine in brain areas promoting sleepiness

Question 15

Gases

1. structure
2. soluble gases
3. neurons use 2 gases as neurotransmitters

Answer 15

1. fluid substance, expands freely to fill available space irrespective of its quantity
2. dissolve in fluid (dependant on pressure & temperature)
3. nitric oxide & carbon monoxide

Question 16

Gases - nitric oxide (NO)

1. named
2. in the brain NO is produced from
3. NO’s function in the brain

Answer 16

1. molecule of the year 1992
2. amino acid arginine in a subpopulation of 1-2% of neurons in the cortex
3. unclear
   - involved in learning & memory through effects on synaptic plasticity
   - dilated blood vessels in regions of the brain that become metabolically active

Question 17

Gases - NO
= very different to traditional neurotransmitters (4)
-> it can act on

Answer 17

1. NOT synthesised and stored in vesicles
2. produced throughout the cell including dendrites & diffuses out as soon as its produced
3. NOT activate receptors but enters neighbouring cell
4. very short lived & degraded/reacted within a few seconds of being produced

-> several nearby neurons (even those not connected by a synapse). However area is restricted due to short lifespan