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Neuroscience Ch 5 (Synaptic Transmission) Vocab

Terms in this set (47)

Presynaptic
Referring to the compartment of a neuronal process (typically, a terminal of an axon) at a synapse specialized for transmitter release; upstream at a synapse
Postsynaptic
Referring to the compartment of a neuronal process (typically, a dendritic spine or shaft)or a location on a cell body that is specialized for transmitter reception; downstream at a synapse
Gap Junction
Specialized intercellular contacts formed by channels that directly connect the cytoplasm of two cells
Connexon
Precisely aligned, paired transmembrane channels that form gap junctions between cells. They are formed from connexins, members of a specialized family of channel proteins
Synaptic Cleft
The space that separates pre- and postsynaptic neuron sat chemical synapses.
Synaptic Vesicles
Spherical, membrane-bound organelles in presynaptic terminals that store neurotransmitter molecules and associated molecular machinery that facilitates exocytosis.
Neurotransmitters
Substances released by synaptic terminals for the purpose of transmitting information from one cell (the presynaptic cell) to another (the postsynaptic cell).
Connexins
Precisely aligned, paired transmembrane channels that form gap junctions between cells. They are formed from connexins, members of a specialized family of channel proteins.
Active Zone
The location within the presynaptic terminal where synaptic vesicles fuse with the presynaptic plasma membrane to discharge their neurotransmitters into the synaptic cleft
Postsynaptic Density
A cytoskeletal junction in developing synapses that may serve to organize postsynaptic receptors and speed their response to neurotransmitters.
Exocytosis
A form of cell secretion resulting from the fusion of the membrane of a storage organelle, such as a synaptic vesicle, with the plasma membrane
Acetylcholine (ACh)
Neurotransmitter at motor neuron synapses, in autonomic ganglia, and in a variety of central synapses. Binds to two types of AChRs, either ligand-gated ion channels (nicotinic receptors) and G-protein-coupled receptors (muscarinic receptors)
Co-Transmitters
Two or more types of neurotransmitters within a single synapse; may be packaged into separate populations of synaptic vesicles or co-located within the same synaptic vesicles
Small Clear-Core Vesicles
A type of synaptic vesicle characterized by a small diameter (typically on the order of 50 nanometers) and an absence of an electron-dense core. These vesicles typically contain and release small-molecular neurotransmitters, such as acetylcholine, glutamate and GABA.
Axonal Transport
The process that allows cellular components, such as proteins and organelles, to move within the axons of neurons.
Large Dense-Core Vesicles
A type of synaptic vesicle characterized by a large diameter (typically 90-250 nanometers) and the presence of an electron-dense core. These vesicles typically contain and release neuropeptides.
End Plates
The complex postsynaptic specializations at the site of nerve contact on skeletal muscle fibers.
End Plate Potential (EPP)
Depolarization of the membrane potential of skeletal muscle fiber, caused by the actions of the transmitter acetylcholine at the neuromuscular synapse.
Miniature End Plate Potentials (MEPPS)
Small, spontaneous depolarization of the membrane potential of skeletal muscle cells, caused by the release of a single quantum of acetylcholine.
Synaptic Vesicle Cycle
Sequence of budding and fusion reactions that occurs in presynaptic terminals to maintain the supply of synaptic vesicles
Synapsin
A protein which reversibly binds to synaptic vesicles and is responsible for tethering these vesicles within a reserve pool.
Ca2+/Calmodulin-Dependent Protein Kinase, type II (CaMKII)
A protein kinase that is activated by the second messenger, calcium ions, binding to the calcium-binding protein calmodulin. Once activated by calcium and calmodulin, this protein kinase can phosphorylate numerous substrate proteins to alter their signaling properties.
NSF
NEM-sensitive fusion protein. An enzyme responsible for dissociating complexes of SNARE proteins
SNAPs
Soluble NSF-attachment proteins. A protein that attaches the enzyme NSF to SNARE complexes, to allow NSF to dissociate the SNARE complexes.
SNAREs
SNAP receptors. Proteins that are found on two membranes and are responsible for fusing the two membranes together.
Synaptobrevin
A SNARE protein located in the membrane of synaptic vesicles. This protein forms a SNARE complex with syntaxin and SNAP-25 that mediates fusion of synaptic vesicles with the presynaptic plasma membrane.
Syntaxin
A SNARE protein found primarily in the plasma membrane. This protein forms a SNARE complex with synaptobrevin and SNAP-25 that mediates fusion of synaptic vesicles with the presynaptic plasma membrane.
SNAP-25
A SNARE associated with the plasma membrane. This protein forms a SNARE complex with synaptobrevin and syntaxin that mediates fusion of synaptic vesicles with the presynaptic plasma membrane.
Synaptotagmins
A family of calcium-binding proteins found in the membrane of synaptic vesicles and elsewhere. 1 and 2 serve as the calcium sensors that trigger the rapid release of neurotransmitters.
Clathrin
The most important protein for endocytotic budding of vesicles from the plasma membrane; its three-pronged "triskelia" attach to the vesicular membrane to be retrieved.
Dynamin
A GTP-hydrolyzing enzyme involved in the fission of membranes during endocytosis.
Actin
A cytoskeletal protein involved in maintaining cell shape and organelle movement.
Hsc 70
An ATP-hydrolyzing enzyme inolved in dissociation of clathrin-coats on vesicles following endocytosis.
Auxilin
An accessory protein that promotes the actions of HSC70 during vesicle uncoating after endocytosis.
Synaptojanin
A protein involved in uncoating of synaptic vesicles. It works by modifying a vesicular lipid, which serves as a cue for vesicle uncoating by Hsc70
Receptor Molecules
A molecule that binds to chemical signals and transduces these signals into a cellular response
Ionotropic Receptors
Receptors in which the ligand binding site is an integral part of the receptor molecule
G-Proteins
Proteins that are activated by exchanging bound GDP for bound GTP (and thus also known as GTP-binding proteins).
G-Protein-Coupled Receptors
A large family of neurotransmitter or hormone receptors, characterized by seven transmembrane domains; the binding of these receptors by agonists leads to the activation of intracellular G-proteins.
End Plate Current (EPC)
A macroscopic postsynaptic current resulting from the summed opening of many ion channels; produced by neurotransmitter release and binding at the motor end plate
Reversal Potential
Membrane potential of a postsynaptic neuron (or other target cell) at which the action of a given neurotransmitter causes no net current flow
Postsynaptic Current (PSC)
The current produced in a postsynaptic neuron by the binding of neurotransmitter released from a presynaptic neuron
Postsynaptic Potential (PSP)
The potential change produced in a postsynaptic neuron by the binding of neurotransmitter released from a presynaptic neuron
EPSPs
Postsynaptic potentials that increase the probability of firing a postsynaptic action potential
IPSPs
Postsynaptic potentials that decrease the probability that a postsynaptic cell will generate an action potential
Summation
The addition in space and time of sequential synaptic potentials to generate a postsynaptic response larger than that produced by a single synaptic potential
Tripartite Synapse
A three-way junction involving a presynaptic terminal, a postsynaptic process, and neighboring glia
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