Scientists at the University of Washington in Seattle have determined the atomic architecture of a sodium channel. The achievement opens new possibilities for molecular medicine researchers around the world to design better drugs for pain, epilepsy and heart rhythm disturbances. Sodium channels are pores in the membranes of excitable cells – such as brain nerve cells or beating heart cells – that emit electrical signals. Sodium channels selectively open and close to allow the passage of millions of tiny charged particles across the cell membrane. The gated flow of sodium ions generates tiny amounts of electrical current.