CNS synapses and neurotransmitters Flashcards
what is a chemical synapse?
-neurotransmitters cross a synaptic cleft to postsynaptic structure
what is an electrical synapse?
- gap junctions
- direct passage of current
what are cell adhesion molecules? why are they important?
- transmembrane proteins that bridge the synapse
- critical for synapse formation and structural plasticity
postsynaptic receptors are coupled to scaffolding proteins, which then link to ____________. what does this protein-protein interaction do?
- postsynaptic receptors are coupled to scaffolding proteins, which then link to cytoskeletal proteins
- through these interactions, neurotransmission can lead to structural and functional changes to the synapses
go through the 7 steps of the chemical synapse
- precursors enter the cell
- Neurotransmitter synthesis
- vesicular transporter (package NT)
- Postsynaptic receptor(binds to NT and exhibits a response)
- Release-modulating autoreceptor (on presynaptic side to regulate presynaptic terminal)
- Presynaptic re-uptake transporter (sits on membrane of pre and recycles NT back into pre as it starts to accumulate)
- Astrocyte clearance (clears excess NT)
what is the difference between neurtransmitters and neuropeptides?
- Neurotransmitters: enzymes and vesicles are transferred from the soma to the axon terminal, then the NT is synthesized in terminal
- Neuropeptide: synthesized in soma, then vesicle and NT are transported to the axon terminal
what are the two ways a NT can get into a vesicle?
- Proton pump (ATP dependent)
- Proton/Transmitter anti-porter
-NT use electrochemical gradient to get into the vesicle
what are the two exceptions to NT sequestrantion into a vesicle?
- when NT are synthesized inside of a vesicle
2. Neuropeptides
in resting state, most vesicles are tethered by ______ and not yet docked.
actin
what happens after AP and Calcium influx?
- actin filaments de-polymerize and dis-associate from vesicles
- vesicles dock, fuse, and release, then are recycled
name some amino acid neruotransmitters
- Glutamate(excitatoy)
- aspartate
- GABA (inhibitory)
- Glycine(inhibitory)
- histamine
what are the two categories of biogenic amines?
- catecholamines
- indolamines
name some catecholamines
- dopamine
- norepi
- epi
what is an indolamine?
serotonin (from brain stem neurons)
what is a retrograde messengers?
- released from post-synaptic neuron and act on Pre-synaptic neuron
- regulates neurotransmitter release
what are some examples of retrograde messengers?
-endocannabinoids
-NO
CO
what precursors and enzyme make acetylcholine?
Acetyl CoA + Choline
cholineacetyltransferase
where do we get choline?
-diet or synthesized in liver
where would you find acetylcholine?
forebrain and midbrain
what is the functional significance of acetylcholine?
- memory and attention
- reward seeking behavior
- arousal
- sleep cycle
what is the major excitatory NT in the CNS?
L-glutamate
what are the three sources of Glutamate and what is the enzyme?
- 2 from mitochondria and 1 from astrocytes
- glutamate dehydrogenase
what happens to AMPA glutamate receptors when there is an influx of Calcium and EPSP? what happens when there is lack of stimulation or IPSP?
Calcium influx: addition of more AMPA glutamate receptors
IPSP: removal of AMPA glutamate receptors
AMPA and Kainate receptors select for what ions? what type of channel are they?
- Potassium and calcium
- ligand gated
