 Ball and chain inactivation

A tethered intracellular particle blocks an open ion channel from the cytoplasmic side. In classical Shaker-type channels the particle is N-terminal: removing it suppresses fast inactivation, while cytoplasmic application of a corresponding peptide can restore block. The pore-blocking mechanism differs from ordinary activation-gate closure.

Ball and chain inactivation is a mechanism by which certain types of ion channels, particularly voltage-gated sodium (Na⁺) channels, become inactive after they have opened in response to a change in membrane potential. This process is crucial for the proper functioning of action potentials in excitable tissues, such as neurons and muscle cells.