What are ion channels called that open or close based on changes in the membrane potential?

Ion channels that open or close in response to changes in membrane potential are referred to as voltage-gated channels. These channels are crucial for the generation and propagation of action potentials in neurons and muscle cells. When the membrane depolarizes, a voltage change triggers a conformational change in the channel protein, resulting in the opening of the channel. This allows specific ions, such as sodium or calcium, to flow into or out of the cell, further influencing the electrical activity of the cell.

Voltage-gated channels are essential in various physiological processes, including synaptic transmission and muscle contraction, making them a fundamental component of cellular communication. The specificity of their function in relation to membrane potential distinguishes them from other types of ion channels, such as ligand-gated channels, which open in response to the binding of a chemical messenger, or mechanogated channels, which respond to mechanical forces. Porins, on the other hand, are involved in the passive diffusion of molecules across membranes and do not operate on the principle of voltage sensitivity.