Dr. Zakon studies ion channels. These are proteins that are found in the membranes of excitable cells like nerves, heart, and muscle. These proteins function as little channels to let ions such as sodium, potassium, and calcium pass into and out of cells. They are essential for proper electrical activity of nerve, muscle, and cardiac cells. In fact, in the last 5 years numerous neurological, muscle, and heart diseases have been linked to mutations in various ion channels in humans. The channels Dr. Zakon studies are potassium and sodium channels. These ion channels are in the electric organ of the electric fish. This organ produces electric discharges that allow these fish to shock prey--as the electric eel does with its strong electric organ--or to navigate in total darkness and communicate with others of its species as occurs in those fish with weak electric organs. Dr. Zakon studies the ion channels of its electric organ because the electric discharge is different in males and females and is influenced by sex hormones such as testosterone and estrogen. Thus, work on the ion channels of electric fish allows a further understand how hormones might influence ion channels of the neurons in our brains. This may help us know how sex differences in the brain come about. In addition, Dr. Zakon is studying how the actvity of these channels is regulated at the molecular level. How do the cells know which kind of ion channel to make, how do they know how many to make, and how do they regulate their activity? This will have implications for all the ion channels in our bodies.