Table of Contents
Gap Junctions,
Electrotonic Synapses
Electrotonic Synapses Discovered
Properties of Gap Junctions (GJ) and
Electrotonic Synapses (ES)
Ultrastructure
Molecular
Gap Junction Channel Formation
Gap Junction Channels
Freeze-fracture Gap Junction Plaque
Not all Gap Junctions form "Plaques"
Domain Structure of Connexins
(> 12 cloned so far)
Major function of Gap Junctions is to regulate brain volume
Gap junction
communicating
compartments
Distinctions between Chemical and Electrotonic Synaptic Transmission
Bidirectional
Electrotonic Junctions
Gap Junction Coupling
Junctional Conductance also determined by amount of transjunctional voltage
Modulated by other factors too
Rectifying Electrotonic Synapse (direction of current flow depends on depolarization status)
No Synaptic Delay - SPEED!
Electrotonic and Synaptic Junctions can be mixed in all combinations on the same cell
Dye-coupling - LM indicator of Gap Junctions
Thalamic - Neocortical Slice Setup
Firing patterns distinguish different types of Cortical interneurons
Chemical Synapses
Review - Begin Here on WEDNESDAY
Other studies have shown that cortical Interneurons have
Electrical (Electrotonic) Synapses
Octanol blocks gap junctions and
electrical coupling
Action Potentials evoked Spikelets
Frequency stimulation to Cell 1
Electrical Synapses Couple Spiking activity of two interneurons
Electrical Synapses Couple Spikeing activity of two interneurons
Occurrence of Electrical Synapses between Pairs of Neocortical Interneurons
Summary Electrical Synapses
Dermietzel, 1993, Fig. 3A
Dermietzel, 1993, Fig. 4
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