12A. Cholinergic neurotransmission Flashcards
6 important Neurotransmitters
The main processes involved in synthesis, storage and release of neurotransmitters
-> identify 1 - 4
1, uptake of precursors;
2, synthesis of transmitter;
3, uptake/transport of transmitter into vesicles;
4, degradation of surplus transmitter;
The main processes involved in synthesis, storage and release of neurotransmitters
-> identify 5 - 8
5, depolarisation by propagated action potential;
6, influx of Ca2+ in response to depolarisation;
7, release of transmitter by exocytosis;
8, diffusion to postsynaptic membrane;
The main processes involved in synthesis, storage and release of neurotransmitters
-> identify 9 - 13
9, interaction with postsynaptic receptors;
10, inactivation of transmitter;
11, reuptake of transmitter or
degradation products by nerve terminals;
12, uptake and release of transmitter by non-neuronal cells;
13, interaction with presynaptic receptors
What is Molecular Model of an Average SV>
How do Vesicular Neurotransmitter Transporters work?
1/ Transmitter uptake into vesicles
2/ Antiporters
3/ Secondary active transporters
4/ Proton gradient is generated by V-ATPases (proton pumps)
Proteins are involved in exocytosis
-> several bacterialvtoxins known to cause neurologic symptoms were proven to inhibit exocytosis by ____
cleaving specific SNARE proteins
Proteins are involved in exocytosis
-> mutation of yeast homologs of the ____ causes defects in membrane trafficking.
SNAREs
Proteins are involved in exocytosis
-> _____ spontaneously form a thermodynamically stable 1:1:1 complex.
syntaxin, synaptobrevin, and SNAP-25
What is synaptotagmin?
major calcium-binding protein
What does SNARE proteins include?
“SNAP REceptor”
Soluble NSF attachment proteins (SNAP)
N-ethylmaleimide-sensitive factor (NSF) ATPase
How do SNARE proteins work?
1/ Assembly of pre-fusion SNARE/SM protein complex
2/ Activation of pre-fusion SNARE/SM protein complex by complexin
3/ Ca2+-triggering of fusion-pore opening
4/ Fusion-pore expansion + NSF- & SNAP binding
5/ NSF-mediated SNARE-complex disassembly & vesicle recycling
What are 2 types of Neurotransmitter receptors
1/ Ligand-gated ion channels
2/ G protein-coupled receptors
Major neurotransmitters of the Autonomic nervous system
-> Where do we find cholinergic neurons?
1/ Neuromuscular junction
2/ Autonomic preganglionic fibers
3/ Parasympathetic postganglionic fibers - heart, glands, smooth muscle
2 important types of receptors binding to neurotransmitters in central nervous system?
- nicotinic receptors
- muscarinic receptors
Model of a cholinergic synapse
- High affinity choline uptake („low- affinity” choline uptake in all tissues, phospholipid synthesis)
- ACh synthesis: choline acetyltransferase
- ACh storage: a specific transporter
- ACh release
- ACh inactivation: ACh esterase
What is the inhibitor of the choline transporter?
Hemicholinium
An example of muscarinic agonist
Arecoline
2 examples of muscarinic antagonist
Atropine and benzotropine
What is the inhibitor of vesicular acetylcholine transporter?
Vesamicol
2 inhibitors of ACh release
Botulinus and tetanus toxins
What is the molecule stimulating ACh release
black window spider toxin
What are the 3 inhibitors of AChE?
(Acetylcholinesterase (AChE) is a cholinergic enzyme primarily found at postsynaptic neuromuscular junctions, especially in muscles and nerves)
Tacrine, galantamine and physostigmine
What are the 2 nicotinic antagonists?
Curare and mecamylamine
