Gap Junctions as Electrical Synapses

  • Michael V. L. Bennett
Part of the Neuroscience Intelligence Unit book series (NIU.LANDES)


A synapse can be defined as a specialized site of functional interaction between neurons. By this definition gap junctions form one class of electrical synapse.1 There is another kind of electrical synapse that mediates short latency inhibition of the Mauthner cell of teleost fishes; this form of electrical transmission is not mediated by gap junctions, but involves a different kind of junctional specialization.2 In addition, there probably are electrical effects that occur between closely apposed cells without obvious gap junctions or specialization other than the absence of interposed glia.2,3 Whether these sites are to be considered synapses or incidental or accidental sites of interaction is a matter of opinion. I have no difficulty in using the term electrical synapse only for gap junctions between neurons and not for gap junctions between nonneuronal cells. Admittedly, this terminology leads to different names for gap junctions depending on where they are located, even when they are comprised of the same protein. However, I find less attractive the alternatives of calling the neuronal interactions mediated by gap junctions nonsynaptic or of using synapses to denote the junctions between such cells as hepatocytes. As will be seen below, transmission mediated at electrical synapses of the gap junction type can be very synaptic in its properties.


Electric Organ Electrical Transmission Chemical Synapse Electrical Synapse Junctional Conductance 
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© Springer-Verlag Berlin Heidelberg 1996

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  • Michael V. L. Bennett

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