Term
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Definition
Process through which new synapses are formed, identified by several physical landmarks:
1. Growth cone looses filopodia and forms close contact with postsynaptic cell membrane
2. Golgi apparatus and coated vesicles accumulate at the postsynaptic membrance
3. Vesicles accumulate in the presynaptic terminal
4. Dendrites make initial contact with axons
5. Glial cells prevent inital contact between axons and postsynaptic cell body
6. Vessicle accumulation/postsynaptic density can form even in the absence of synapse |
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Term
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Definition
| When filopodia come into contact with postsynaptic membrane (only with postsynaptic membrane) there is a sharp increase in calcium in the growth cone which leads to morphological changes associated with synaptic maturation. |
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Term
| Cell Adhesion Molecules in Synapse Formation |
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Definition
After contact with target, adhesion of the axon and postsynaptic membrance increases. NCAM's are expressed in the cell surfaces of both cells at synapses and make tight junctions. These receptor-ligand interactions can promote of vesicle accumulation to form the action zone.
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Term
| Patch-Clamp Method (outside-out) |
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Definition
Method through which a small piece of cell membrane is isolated at the tip of a needle. The flow of ions from receptors in this patch of membrane can be measured. Using this method, you can see that soon after contact, the synapse matures (measured by increase in spontanous post-synaptic current and also increased strength of evoked post-synaptic current)
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Term
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Definition
Synaptic maturation is marked also by an increased clustering of receptors in the postsynaptic membrane
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Term
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Definition
| The basal lamina is a layer of ECM proteins that surround muscle cells. AChRs accumulate underneath the basal lamina despite denervation. |
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Term
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Definition
| Signaling molecule produced by the presynpatic neuron that induces MuSK (its receptor) to cluster AChRs. |
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Term
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Definition
| Muscle Specific Kinase-- receptor to Agrin which causes the clustering of AChR |
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Term
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Definition
| Intracellular protein that is involved in receptor clustering in the CNS (glycine recptor) |
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Term
| Denervation supersensitivity |
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Definition
| NT release can influence postsynaptic receptor expression/clustering. Hence if TTX cuff is applied (dennervation) a supersensitivity might ensue. |
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Term
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Definition
| Growth Factor that mediates changes in AChR subunit composition |
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Term
| Neurotransmitter Re-uptake Changes |
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Definition
| As synapse matures, it produces NT re-uptake proteins. Hence synapse is capable of producing cripser, cleaner signals and is more responsive (the NT is being continouly and efficiently cleared from the synapse). |
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Term
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Definition
Receptors have different types of subunits and the use of particular subunits is capable of changing during development.
(e.g. GABAR has 13 forms of subunits, and certain types are utilized more in receptors of adults) |
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Term
Length of Synaptic Potential
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Definition
The length of synaptic potentials is related to how long the ion channels/receptors remain open which has to do with which specific types of subunits they are constructed
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