Plasticity at electrical synapses

Abstract

Trafficking of transmitter receptors to maintain and modify strength of chemical synapses has been characterized extensively. However, trafficking of gap junction components at electrical synapses is little known, although turnover time of connexin gap junctions in, e.g., heart, liver, and recombinant systems, is a few hours. We combined ultrastructural and physiological analysis at mixed (electrical and chemical) synapses on the goldfish Mauthner cell. Both components can exhibit LTP and LTD. As at other gap junctions, hemichannels are added at the adges of GJ plaques where they dock with hemichannels in the apposed membrane to form cell-cell channels, and intact junctional regions are removed from the centers of these plaques into either presynaptic axon or postsynaptic dendrite. Moreover, electrical coupling is modified by intradendritic application of peptides that interfere with endocytosis or exocytosis. [...].