5.14 - Synapses and Synaptic Models Flashcards
Which is faster, an electrical or a chemical synapse?
An electrical synapse is instantaneous. But note that it tends to be low pass filtered.
What is the major cause of short-term synaptic depression?
Depletion of synaptic vesicle in the presynaptic terminal. (extra info: alternatively, postsynaptic receptors can be desensitised after repeated activation.)
What is the quantal hypothesis/quantal theory of synaptic transmission?
Synaptic transmission are composed of discrete quanta which are individual neurotransmitter-containing vesicles that are released at the presynaptic terminal.
How can a facilitating synapse (a synapse that shows facilitation) reduces noise in information transfer?
Single, isolated action potentials (noise) in the presynaptic cell will not be well transmitted to the postsynaptic cell, while bursts of activities (signal) will be especially effective at affecting the postsynaptic cell.
What are the two main types of receptors based on mode of action?
Inotropic receptors (ion channels) and metabotropic receptors (G-protein coupled receptors).
What is Hebbian plasticity?
If neuron A repeatedly or persistently takes part in firing neuron B the efficiency in which neuron A excites neuron B will increase.
What are the typical mechanisms of long-term potentiation?
Recruitment of AMPA receptors facilitation of synaptic release
What is “cooperativity” in the context of ligand-protein binding? Give an example of positive cooperativity.
Cooperativity in ligand-protein binding refers to the phenomenon that for a protein with multiple binding sites, the binding of the first ligand can change the binding/unbinding rate of the second, third, etc. ligand. Hemoglobin has positive cooperativity, in which the binding of the first oxygen molecule makes it the binding of the next molecule easier.
How can you model a protein with multiple binding sites using ODE?
By specifying all the bound states (unbound, single bound, double bound, etc) and the rate of transition between the different states. The rate of change of each state can be described as a differential equation.
What are the two main types of synapses?
Electrical synapse and chemical synapse
What is the major molecule that forms an electrical synapse?
connexin (6 connexin -> 1 connexon)(2 connexon-> 1 gap-junxtion channel)
Which are the major excitatory and inhibitory neurotransmitter in the central nervous system?
Glutamic acid (glutamate) is the major excitatory neurotransmitter. GABA is the major inhibitory neurotransmitter.
How are the two types of short-term synaptic plasticity called?
Depression and facilitation.
What are the theorized functions of synaptic facilitation?
Counteracting depression. Temporal filtering. Optimize information transfer. Working memory.
What properties of NMDA receptor help it mediate long-term potentiation?
1) It has a extracellular magnesium block and thus only opens during large depolarizations. 2) It allows the flow of Ca2+ into the cell to act as a signal for metabolic processes.
