CNS synapses and neurotransmitters Flashcards Preview

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Flashcards in CNS synapses and neurotransmitters Deck (35)
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1
Q

what is a chemical synapse?

A

-neurotransmitters cross a synaptic cleft to postsynaptic structure

2
Q

what is an electrical synapse?

A
  • gap junctions

- direct passage of current

3
Q

what are cell adhesion molecules? why are they important?

A
  • transmembrane proteins that bridge the synapse

- critical for synapse formation and structural plasticity

4
Q

postsynaptic receptors are coupled to scaffolding proteins, which then link to ____________. what does this protein-protein interaction do?

A
  • 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
5
Q

go through the 7 steps of the chemical synapse

A
  1. precursors enter the cell
  2. Neurotransmitter synthesis
  3. vesicular transporter (package NT)
  4. Postsynaptic receptor(binds to NT and exhibits a response)
  5. Release-modulating autoreceptor (on presynaptic side to regulate presynaptic terminal)
  6. Presynaptic re-uptake transporter (sits on membrane of pre and recycles NT back into pre as it starts to accumulate)
  7. Astrocyte clearance (clears excess NT)
6
Q

what is the difference between neurtransmitters and neuropeptides?

A
  • 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
7
Q

what are the two ways a NT can get into a vesicle?

A
  • Proton pump (ATP dependent)
  • Proton/Transmitter anti-porter

-NT use electrochemical gradient to get into the vesicle

8
Q

what are the two exceptions to NT sequestrantion into a vesicle?

A
  1. when NT are synthesized inside of a vesicle

2. Neuropeptides

9
Q

in resting state, most vesicles are tethered by ______ and not yet docked.

A

actin

10
Q

what happens after AP and Calcium influx?

A
  • actin filaments de-polymerize and dis-associate from vesicles
  • vesicles dock, fuse, and release, then are recycled
11
Q

name some amino acid neruotransmitters

A
  • Glutamate(excitatoy)
  • aspartate
  • GABA (inhibitory)
  • Glycine(inhibitory)
  • histamine
12
Q

what are the two categories of biogenic amines?

A
  • catecholamines

- indolamines

13
Q

name some catecholamines

A
  • dopamine
  • norepi
  • epi
14
Q

what is an indolamine?

A

serotonin (from brain stem neurons)

15
Q

what is a retrograde messengers?

A
  • released from post-synaptic neuron and act on Pre-synaptic neuron
  • regulates neurotransmitter release
16
Q

what are some examples of retrograde messengers?

A

-endocannabinoids
-NO
CO

17
Q

what precursors and enzyme make acetylcholine?

A

Acetyl CoA + Choline

cholineacetyltransferase

18
Q

where do we get choline?

A

-diet or synthesized in liver

19
Q

where would you find acetylcholine?

A

forebrain and midbrain

20
Q

what is the functional significance of acetylcholine?

A
  • memory and attention
  • reward seeking behavior
  • arousal
  • sleep cycle
21
Q

what is the major excitatory NT in the CNS?

A

L-glutamate

22
Q

what are the three sources of Glutamate and what is the enzyme?

A
  • 2 from mitochondria and 1 from astrocytes

- glutamate dehydrogenase

23
Q

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?

A

Calcium influx: addition of more AMPA glutamate receptors

IPSP: removal of AMPA glutamate receptors

24
Q

AMPA and Kainate receptors select for what ions? what type of channel are they?

A
  • Potassium and calcium

- ligand gated

25
Q

NMDA receptors select for what ions?

A

-potassium, calcium, and sodium

26
Q

why are ionotropic receptors excitatory?

A

they let their cations in, which makes the potential less negative and pushes it to threshold

27
Q

what is the purpose of the Mg site in NMDA receptors?

A

-acts as a block and depolarization releases the block

28
Q

increased amounts of glutamate means increased amounts of calcium, which can result in what?

A

necrosis and cell death

29
Q

what is the major inhibitory NT in the CNS?

A

GABA

30
Q

GABA is synthesize from what and by what?

A

from glutamate by glutamic acid decaroxylase

31
Q

what is GABA metabolized by?

A

mitochondrial enzymes

32
Q

what does GABA(a) receptor do?

A

it hyperpolarizes to make potential more negative

33
Q

what is the clinical significance of GABA?

A
  • deficiency results in increase in neuronal excitability

- GABA dysfunction leads to seizures

34
Q

what is the clinical significance of glutamate?

A
  • concept of glutamate excitotoxicity

- target for general anesthetics

35
Q

what NT is important for neuronal plasticity?

A

glutamate (learning/memory)