05.Synapse and receptor

Synapse and receptor

What is left from last section: calcium-activated potassium channels, low-threshold and high-threshold calcium-activated potassium channels, are responsible for post-inhibitory-rebound and adaptation respectively.

Calcium dynamics

Calcium concentration varies in different parts of neuron: soma, dendrite and spines, enabling neurotransmitter release, action potential generation and synapse stabilization.

Synapse

Synapses could be classified as inhibitory synapses (mainly using GABA as neurotransmitter) and excitatory synapses (adopting glutamate as neurotransmitter).

The activation of post-synaptic element is realized by binding of neurotransmitter and receptor, ion channel opening and post-synaptic current (or potential) generation, or other intracellular cascade. The amount of current pass through a specific synapse could be described as a function of synaptic conductance $\mathrm{g_{syn}}$ and driving potential.

The conductance of synapse is an exponential decay function:

for inhibitory synapse, which has two types of current components:

for excitatory synapse, which adapts two types of receptors: NMDA (slow) and AMPA (fast):

with $g_{\infty} = (1+e^{\alpha u}[\mathrm{Mg}^{2+}]_o/\beta)^{-1}.$

Receptors

See this reference for differences between AMPA and NMDA receptor. http://www.sumanasinc.com/webcontent/animations/content/receptors.html

Spatial structure of dendritic tree

Cable equations based on Kirchhoff’s law. See Green’s function solving the stationary solution of cable equations in next section.

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