Basic mechanisms of voltage sensing

Since the early pioneering studies by Bernstein, Cole, Hodgkin, Huxley, and others, voltage-sensitive conductances have been extensively studied because of their primary role in electrical excitability in nerves and muscles (2-11). Voltagedependent K⁺, Na⁺, and Ca⁺⁺ channels are responsible for generation of an action potential, which is the elementary unit of electrical signals in biology. Calcium inux through calcium channels can also act as a second messenger, which initiates various processes such as muscle contraction (12, 13). Isoforms of voltage-dependent potassium channels are involved in diverse physiological processes, which include volume regulation, secretion, proliferation, and migration.