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25 Cards in this Set
- Front
- Back
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Where are electrical synapses found |
-Cardiac Muscle Cells -Epithelial Cells |
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Gap junctions; what are they used in (1), how do they work(3), features (2) |
-Used for electrical syntaptic transmission
-Bridge gaps between two spaces -Low impedence pathway for current -Pore is made of a protein called connexin
-Can be bidirectional/unidirectional -No Delay in transmission |
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Who first demonstrated chemical transmission? |
-Otto Loewi (1921) -The double frog heart experiment |
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Criteria for idenfitying a neurotranmisster |
Effects in presynaptic neuron -Has to be produced and stored here -Has to be released when excited here Effects in post-synaptic neuron -When experimentally applied to post-synaptic neuron has to mimic normal transmission -Should be a mechanism for removing substance from the synaptic cleft -Drugs that act postsynaptically to affect normal transmission should affect responses to candidate NT in same way |
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What is the end of an axon which branches into many axon terminals called? |
Telondron |
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Is serotonin generally excitatory or inhibitory? |
Inhibitory |
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Is dopamine generally excitatory or inhibitory? |
Excitatory (Generally) |
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Is glutamate generally excitatory or inhibitory? |
Excitatory |
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Is gamma aminobutyric acid generally excitatory or inhibitory? |
GABBA is inhibitory |
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Is achtylcholine generally excitatory or inhibitory? |
Mixed |
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Is norepinephrine generally excitatory or inhibitory? |
Mixed |
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Name three biogenic amine NTs? |
Serotonin Dopamine Norepinephrine |
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Name Two amino acid NTs |
Glutamate GABBA (Glycine, Aspartate) |
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What is the processes of when a NT is released into the synpatic cleft? |
Exocytosis |
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Mechanism of NT release (4- general points) |
-Presynpatic nerve terminal depolarises -Voltage-gated Ca+ channels open -Ca+ enters the terminal -Causes the vesicle to fuse with active zone and release molecules into the cleft |
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Two groups of SNARE proteins? |
V-SNARE - Vesicle Membrane Proteins T-SNARE - Target Membrane Proteins |
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What does SNARE proteins do? |
V-SNARE: Senses calcium, helps fusion T-SNARE |
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Which SNARE protein senses calcium and aids in fusion? |
Synaptotagmin |
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Reuptake Process ( |
-NTs are too large and hydrophillic to diffuse through the membrane -Taken back via transport proteins via ion gradient and absorbed back into celll |
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Recycling Vesicles |
-CLATHRIN coats remnant of fused vesicle -DYNAMIN pinches off the vesicle from the membrane -ATPase removes coating of clathrin ... no more detail in slides... |
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Two types of NT receptor, main difference
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Ionotropic and Metatropic Receptor. -Ionotropic receptors: mixes transmitter-binding and channel functions into one molecular entity. Rapid and short-duration -Metabotropic receptors: G-protein-coupled-receptor. Longer onset and duration of responses. |
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How does Ionotropic Receptors work? |
-NT binds to receptors -Opens NA+ / K+ permeable channels - |
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Two methods of regulation of receptors: |
-Densitization & Down-regulation |
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Two types of summation |
Spatial summation: -When EPSPs from two or more neurons activate simultaneously generate a potential Temporal Summation -When a single presynaptic neuron generates an action potential by rapid firing |
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IPSP- how? |
-Chemically gated K+ or Cl- channels! -Selective to either ion -Causes hyperpolarisation |
