In some clinical applications, it is desirable to arrest
or block propagating action potentials and eliminate the
possibility of neurotransmitter release from the axons. Action
potentials are propagating signals that are transmitted by
neurons and can be initiated by natural or artificial inputs
to their neuronal membrane. When the initiating signal causes
a change in the local transmembrane potential a self-propagating
depolarization signal can be generated. This self-propagating
action potential signal, which is an active process by entry
of Sodium through ion channels in the membrane, travels along
the length of the axon.
The conduction of this signal can be prevented by rendering a section of the
axon unresponsive to this traveling wave of depolarization. Bio-toxins like Tetradotoxin
and some local anesthetics like Lidocaine do this by binding to the Sodium channels.
These chemical methods cannot be reversed quickly and can have wider responses
on other organ systems. Manipulating the excitability of the membrane ion channels
through applied electric fields or altering the temperature may enable one to
rapidly induce and reverse block of action potential propagation.