Role of electrical synapses in vision

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Chemical and electrical communication are the two known types of transmission used in the nervous system. Historically, electrical transmission was already known by the 1940-1950s, but the functional significance largely ignored and controversially discussed. Today, it is agreed that two distinct families of channel forming proteins, the pannexins and connexins, participate in electrical communication, but we don't understand the rules and mechanisms of these processes in detail. It is my goal to demonstrate the physiological relevance of electrical transmission in particular in the visual system from molecules to systems to behavior. Major steps forward were achieved recently. We could prove that one molecular determinant of electrical transmission in the outer retina is a connexin protein. In addition, we demonstrated that chemical and electrical synapses share similar molecular mechanisms to achieve synaptic plasticity. Now, these exiting results let us address the functions of electrical synapses from a different angle by studying how major signaling pathways utilizing calcium, ATP and nitric oxide converge on the structure of two distinct pannexin proteins. A systematic and context dependent structure-function analysis as outlined will provide important novel insight into critical protein structures, channel functions and regulatory circuits in vitro, with the gain in knowledge applicable for rational design of animal models to address channel functions in neuronal network plasticity and behavior in vivo. These studies will form the basis to fit synaptic transmission through pannexins into physiologically meaningful regulatory networks linking major signaling pathways to function(s) of the visual system.