1.9 Synaptic Transmission Pt. 1 Flashcards
What are the general characteristics of Gap Junctions?
- Fast, bidirectional
- Channels are large/unselective. Metabolic signals can be passed
Where are gap junctions found?
In cardiac muscles, and some smooth muscle
Cardiac Ventricular, uterus, bladder
What type of synapse is a a Gap junction?
Electrical Synapses
What are Stellate cells?
Are neurons with several dendrites radiating from the cell body giving them a star shape.
Where are the vesicle, peptide, and enzymes synthesized in the neuron?
Golgi
Where are non-peptide neurotransmitters made?
Synthesized in the nerve terminal and transported into the vesicle.
What are the three steps to regulation of synaptic vesicle exocytosis?
i. Targeting
ii. Discharge of transmitter by exocytosis
iii. Recycling of membrane
What are the three steps of targeting in the regulation of synaptic vesicle exocytosis?
1) Rab protein binds to GTP
2) Hydrolysis of GTP to GDP and inorganic phosphate could be part of the targeting of the vesicle to docking sites
3) Rab proteins are recycled back into the cytoplasm.
What is SNARES?
soluble N-ethylmaleimide-senstiive factor attachment receptors
What is required for exocytosis of synaptic vesicles?
Munc18
What do synapsins do during transmitter release?
i. Substrates for cAMP-dependent protein kinase and Ca2+/calmodulin dependent protein kinase
ii. When no-phosphorylated the synapsins bind to vesicles to actin filaments in the cytosol.
iii. When phosphorylated due to Calcium entry, the synapsins release the vesicles allowing them to move into the active zone.
What are the steps of vesicle docking and priming?
i. Vesicle proteins ((synaptobrevin) VAMP)
ii. Interact with membrane proteins (SNAP-25 and syntxin)
iii. Dock vesicle to the presynaptic membrane
What cleaves SNARE proteins?
Neurotoxins
What does Munc18 bind to?
synaptobrevin, but will bind to syntaxin first if present
What does Tetanus target and cleave?
VAMP