Sandbox WWC3

From Proteopedia

Sodium channels ^[1] are voltage gated integral membrane proteins found in muscles and neurons that selectively allow for the diffusion of sodium ions across the membrane. These proteins important for all cells but are specifically responsible initiating electrical signaling in these cells ^[2] and are commonly targets of drugs and mutation. Each sodium channel is composed of two subunits: the alpha subunit, which is the ion channel transmembrane domain ^[3], and two beta subunits that modulate channel gating and regulate the channel expression in the membrane ^[4].

Function

Sodium channels initiate action potentials in nerve and muscle cells. These electrical signals initiate the contraction of muscles and the release of neurtransmitters. The electrical signal is propogated when the sodium challen allows the influx of sodium ions. These positively charged ions depolarize the resting membrane potential of -70mV to +40mV, which creates the electrical signal that is sent along the length of the cell.The initial influx of sodium ions is often activated by the binding of a neurotransmitter to receptors on the post-synaptic membrane ^[5]. Then, as the sodium ions depolarize the membrane potential. more sodium channels open, and the action potential moves along the length of the muscle or nerve. The channels inactivate after 1-2ms ^[6] and the depolarization is then reversed by the efflux of potassium ions out of potassium channel^[7]. This information was first discovered by Hodgkin and Huxley in 1952^[8]. For more information on the role of sodium channels in electrical signaling, visit