Peptides, lipids, nucleosides, gases Flashcards
Why are peptides, lipids, nucleosides, gases not NTs?
Do not satisfy ALL criteria for a Neurotransmitter
- Present in presynaptic terminals
- Released from presynaptic terminals after neuron fires
- Existence of receptors on postsynaptic neurons
What are peptides, lipids, nucleosides, and gases?
Non-traditional NT
What are the structure of peptides? How is it synthesized?
What do peptides serve as (NT/NM)?
- Consist of 2 or more amino acids (protein are much larger)
- Not synthesized
- Polypeptides broken down into peptides within neuron
- Most peptides serve as modulators, however many peptides known to be hormones also act as neurotransmitters and are often co-release with other neurotransmitters
What is the common NT of peptide?
Endogenous Opiods
What are some examples of opiods?
Morephine, Heroin, Opium
How does heroin affect receptors?
They are Full agonists.
What are other drugs alongside heroin, that acts on the same receptors?
Buprenorphine:
- Partial Agnoist
Naloxone:
- Full antagonist
- Counter heroin
Methadone:
- Full Agonist (SLOW release)(Like Heroin)
- Helps dependent
B-N-M
Is heroin neurotoxic?
- Not neurotoxic (no brain damage)
- Cause death by respiratory failure.
What are opiate drugs known for?
Pain relief and euphoria
Where in the brain has the highest density of opiate receptors?
In areas involved in pain
What are lipids? Function and synthesis pathways.
Lipids
- Naturally occuring molecules - fats, waxs
- Hydrophobic
- Function: Energy storage, signaling
Synthesis
- Unclear. But we know many serve as NT or modulators (modulate the modulators)
What is the best known lipid NT?
Endocannabinoids (endogenous cannibis-like substance)
What are the receptors for endocannabinoids? Where are they found and What do they do?
- CB1 (brain)
- Shorten duration of AP in presynaptic neurons
- Decrease NT released
- Modulating the modulator
- CB2 (peripheral)
What is the active compound in marijuana?
THC
What are effects of cannibis?
Changes in appetite, time perception, arousal (relaxation/anxiety), apathetic states, “underachievement”
What is therapeutic uses of marijuana?
Reduce nausea, relieve asthma, decrease pressure within eyes
What is nucleosides structure and synthesis?
- Subnit of nucleic acid (Link to DNA/RNA)
Synthesis
- Enzymatic breakdown of nucleic acids
- Often “co-transmitters” that serve to modulate the release of other transmitters.. Again modulating the modulators - Similar to Lipids
What do nucleosides do?
“Co-transmitter” that modulate release of other NT
(Similar to CB1 receptors/lipids, modulate modulators)
What are Nucleoside NT?
Adenosine
What is adenosine (excitation/inhibitory)? How are they formed?
- Inhibitory NT
- Forms from breakdown of ATP.
When is adenosine high, which part of the day? What does it do? If adenosine is the primary NT, what happens?
- Awake: Adenosine gradually rise throughout day
- Normal Conditions: Promotes sleep and suppress arousalt
- At synapses where adenosine is the primary NT, a high postsynaptic firing rate = reduced arousal = sleepiness
How does caffeine work with adenosine?
Adenosine-receptor antagonist (block adenosine action)
- Increase firing of adenosine = Sleepy
- Reduce firing of adenosine = Caffeine
- Alert
What are two gases used as NT? What are they produced from?
Nitric (not nitrous) oxide and carbon monoxide
Note: They are NTs
NO
- Produced from the amino acid Arginine in a subpopulation of 1-2% of neurons in cortex.
What is nitric oxide function role in brain?
Unclear.
- But we know it is involved in
- (a) learning and memory through effects on synaptic plasticity
- (b) dilates blood vessels in metabolically active region of brain
