Neurotransmitter Systems Flashcards
What uses slow axonal transport?
Cytostructural components (mitochondria) or ion channels/receptors
What can travel retrograde back to the soma from the synapse?
- neurotrophic substances
- used vesicles and intracellular organelles
- Also some viruses (rabies)
What uses fast axonal transport?
Neurotransmitter vesicles from the soma to the synapse
Name the 3 catecholamine neurotransmitters
Norepiniphrine, epinephrine, and dopamine
What are the catecholamines synthesized from
tyrosine
what is the enzyme for tyrosine to L-DOPA?
tyrosine hydroxylase
where is dopamine beta hydroxylase located?
intracellular vesicular membrane
Where is norepinephrine synthesized?
within vesicles
What enzyme coverts norepinephrine to epinephrine and where does this occur?
PNMT; outside of the vesicle
Where is norepinephrine found in the central nervous system?
locus ceruleus
What does norepinephrine play a crucial role in?
waking us up; awareness
What are the proteins that move the catecholamines into vesicles?
VMATs
Where is VMAT1 found and what does it do?
adrenal medulla; moves both dopamine into the vesicle for its conversion to norepinephrine AND then the epinephrine that was created in the cytoplasm back into the vesicles
Where is VMAT2 found?
any neuron that releases the monoamines
What does VMAT2 do?
1) moves any monoamines into vesicles for either synthesis of norepinephrine or storage prior to release.
2) it can move toxins into the vesicles to protect the neurons from the toxin
What drug are VMAT 1 and 2 sensitive to and what is this drug used for?
Reserpine; hypertension
Which dopamine receptors are Gs coupled?
D1 and D5 (D1-like)
which dopamine receptors are Gi coupled?
D2, D3, and D4 (D2-like)
D1 receptor action
voluntary motion
D2 receptor action
inhibits motion
D3 receptor action
pleasure/reward system
What are the 2 ways to remove catecholamines from the synaptic cleft?
Reuptake and enzymatic destruction
What are the 2 enzymes used for enzymatic destruction of the catecholamines in the synaptic cleft?
MAO and COMT
Serotonin is synthesized from what amino acid?
tryptophan
What is the large cluster of neurons that use serotonin as their neurotransmitter?
midline raphe nuclei
serotonin plays a role in controlling what and disruptions in transmission are associated with what?
attention and mood; depression
How many different 5-HT (serotonin) receptors are there?
SEVEN
How is serotonin removed from the synaptic cleft?
metabolized by MAO AFTER REUPTAKE
What amino acid is histamine derived from?
histidine
Where is histamine found in the central nervous system?
Posterior hypothalamus in the tuberomammillary body