Gap junction channels are composed of two hemichannels called connexons in vertebrates, one contributed by each cell at the synapse.

[2][12][14] Connexons are formed by six 7.5 nm long, four-pass membrane-spanning protein subunits called connexins, which may be identical or slightly different from one another.

[2] However, sometimes the junctions are rectifying synapses,[2] containing voltage-gated ion channels that open in response to depolarization of an axon's plasma membrane, and prevent current from traveling in one of the two directions.

[17] Some channels may also close in response to increased calcium (Ca2+) or hydrogen (H+) ion concentration, so as not to spread damage from one cell to another.

[17] There is also evidence of synaptic plasticity where the electrical connection established can either be strengthened or weakened as a result of activity, or during changes in the intracellular concentration of magnesium.

[21][22] The model of a reticular network of directly interconnected cells was one of the early hypotheses for the organization of the nervous system at the beginning of the 20th century.

Modern understanding of the coexistence of chemical and electrical synapses, however, suggests that both models are physiologically significant; it could be said that the Nobel committee acted with great foresight in awarding the Prize jointly.