MadSci Network: Neuroscience
Query:

Re: what are the activities at the synaptic junction

Date: Tue Dec 19 09:35:49 2000
Posted By: Alexander Craig, Grad student, Physiology/Neurobiology
Area of science: Neuroscience
ID: 976126378.Ns
Message:

I assume you want to know about what happens after an action potential has reached the synapse.
I will start off with a short - but somewhat simplified -recap of how a synapse is schematically structured although you probably already know that:
You have the pre-synaptic cell which usually ends in a so called terminal bouton and 'sends' the chemical signal. In close apposition you find the post-synaptic cell which receives the neurotransmitter signal. Both are separated by a synaptic cleft usually in the range of 25 to 100 nm in width.

When there is no specific signal, the membranes of both pre- and post-synaptic cell are at their resting potential (for simplicity's sake we will neglect the fact that sometimes spontaneous action potentials arrive at the synapse), which is essentially determined by the conductance for different ions (sodium, potassium, chloride) according to the Nernst equation.
So, here's our cell - resting - and what happens at the synapse when the action potential comes rushing in is, briefly, the following:




Image summarizing the events at the synapse; taken from the textbook by Shepherd with some additions by me.
G = G-protein, E = effector, PK = protein kinase

For further questions feel free to email me at this address.

Glossary


References


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