Synthesis, Storage, and Release of Neurotransmitters Flashcards

1
Q

What is the process of synaptic transmission?

A

nt packaged in vesicle> docking> priming> exocytosis> endocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is an electrical synapse?

A

passive communication via direct electrical coupling of 2 cells through gap junctions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a chemical synapse?

A

communication through release and binding of molecules (NT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the name of the pore forming proteins that connnect 2 cells?

A

connexins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Multiple connexins make a …

A

connexon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Two connexons make a ….

A

gap junction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the limitation of electrical synapses?

A

postsynaptic = presynaptic (identical signal, less plasticity)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the advantage of electrical synapses?

A

rapid signal transmission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the limitation of chemical synapses?

A

slower signal transmission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the advantage of electrical synapses?

A

postsynaptic signal varies from presynaptic signal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the 6 types of neurotransmitters?

A
  1. Ach
  2. amino acids
  3. purines
  4. biogenic amines
  5. gases (NO, CO)
  6. peptides
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are NT regulators?

A

BDNF and NGF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the 2 types of amino acid transmitters?

A

inhibitory and excitatory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the characteristics of inhibitory transmitters?

A
  • GABA and glycine
  • IPSPs, influx of Cl- or efflux of K+
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are drug examples of inhibitory transmitters?

A
  • phenobarbital
  • diazepam
  • vigabatrin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the characteristics of excitatory transmitters?

A
  • glutamate, aspartate, Ach, serotonin, histamine
  • associated primarily with EPSPs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are drug examples of excitatory transmitters?

A
  • ketamine
  • riluzole
  • MSG
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the 5 peptide NT?

A
  1. brain out
  2. opioid
  3. pituitary
  4. hypothalamic-releasing
  5. miscellaneous
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the biogenic amines?

A
  • catecholamines
  • histamine
  • serotonin
20
Q

What is the life cycle of a NT?

A

synthesis -> packaging -> release -> binding -> inactivation

21
Q

What is the rate limiting enzyme for the synthesis of catecholamines?

A

tyosine

22
Q

In the synthesis of histamine and seratonin, what does a low 5HT cause?

A
  • depression
  • OCD
  • ADHD
23
Q

What occurs in the synthesis of small molecule transmitters?

A
  1. synthesis of enzymes in cell body, then transported to presynaptic nerve terminal
  2. slow axonal transport of enzymes
  3. synthesis and packing of nt
  4. release and diffusion of nt
  5. tranpsort of precurors into terminal
24
Q

What occurs in the synthesis of peptide transmitters?

A
  1. synthesis of precursors/enzymes
  2. transport of enzymes and pre-peptides down microtubule tracks
  3. enzymes modify pre-peptides to produce peptide nt
  4. nt diffuses away and is degraded by proteolytic enzymes
25
Q

The packaging of nt include what 2 vesicles?

A

clear-core and dens-core

26
Q

What are clear-core vesicles?

A
  • small molecule transmitter synthesized at presynaptic nerve terminal
  • transmitters stored in endosomes which bud off small, clear-core vesicles
27
Q

What are dense-core vesicles?

A
  • large propeptide transmitters synthesized in cell body with enzymes packaged together in dense-core vesicles
  • bud off from golgi and transported along axon
28
Q

What does the vesicle docking complex include?

A
  • vSNARE
  • SNAPs
  • tSNARE
29
Q

What is a vSNARE?

A
  • aka synaptobrevin
  • botulism target
  • many types of SNAREs
  • vesicle docking with presynaptic membrane
30
Q

What is a SNAP?

A
  • soluble NSF attachment protein
  • NSF cofactors
31
Q

What is a tSNARE?

A

target membrane; AKA syntaxin

32
Q

Docking and release of vesicles involves what 2 things?

A

vSNARE and tSNARE

33
Q

What happens during fusion and release (exocytosis)?

A
  1. AP triggers increase in Ca+
  2. synaptotagmin acts as the Ca+ sensor and binds
  3. Ca+ bound synaptotagmin induces vesicular and plasma membrane fusion via interaction with SNAP-25
34
Q

What are the 2 important proteins involved in endocytosis?

A

clathrin and dynamin

35
Q

What is the role of clathrin?

A

coats membrane and begins process of endocytosis

36
Q

What is the role of dynamin?

A

“molecular scissor” which pinches vesicle off membrane

37
Q

What are the characteristics of clostridial neurotoxins?

A
  • cleave SNAREs
  • botulism toxim: blocks exocytosis of Ach vesicles
  • multiple targets: synaptobrevin, syntaxin, SNAP-25
38
Q

What are the 3 methods of inactivation?

A
  1. diffusion of transmitter from synaptic space
  2. cleaving the transmitter into inactive constituents
  3. reuptake of transmitter back into the presynaptic neuron via transporters
39
Q

What is the neuromuscular junction?

A
  • voluntary neuronal stimulus from CNS
  • AP leads to alpha motor neuron stimulation
  • Ach released at postsynaptic membrane in neuromuscular junction
40
Q

What are endplate potentials?

A
  • depolarizations of muscle fibers caused by Ach binding to postsynaptic membrane
  • AP fires -> Ach released -> muscle depolarizes and contracts
41
Q

What are the characteristics of nicotinic Ach receptors?

A
  • ligand gated
  • 2 Ach molecules bind to a single receptor
  • receptor changes conformation to open an ion channel that is equally permeable to Na+ and K+
42
Q

What is the make-up of nAch receptors?

A

functional receptor has 5 subunits where each winds around through plasma 4 times

43
Q

What is the process of a neuromuscular junction?

A
  1. alpha motor neuron stimulation releases Ach
  2. activation of nAch receptor
  3. depolarizing end plate potential
  4. firing of skeletal muscle AP
44
Q

What is Myasthenia Gravis?

A
  • autoimmune disease where Abs targeted against nAch receptors on the postsynaptic membrane
  • pathological effects of nAch receptor blockade
45
Q

What are the symptoms of Myasthenia Gravis?

A

muscle weakness, fatigue, drooping of eyelids

46
Q

What are the precursors, enzymes, and products for biogenic amines?

A
  1. tyrosine -> tyrosine hydroxylase -> dopamine
  2. norepinephrine ->phenethanolamine -> epinephrine
  3. histidine -> histidine decarboxylase -> histamine
  4. tryptophan -> tryptophan-5-hydroxylase -> 5-hydroxytryptophan -> acid decarbxylase -> serotonin