Editing Signal transduction (section)

====Ligand-gated ion channels====
{{Main|Ligand-gated ion channel}}

A ligand-gated ion channel, upon binding with a ligand, changes conformation to open a channel in the cell membrane through which ions relaying signals can pass. An example of this mechanism is found in the receiving cell of a neural [[synapse]]. The influx of ions that occurs in response to the opening of these channels induces [[action potentials]], such as those that travel along nerves, by depolarizing the membrane of post-synaptic cells, resulting in the opening of voltage-gated ion channels.

An example of an ion allowed into the cell during a ligand-gated ion channel opening is Ca<sup>2+</sup>; it acts as a second messenger initiating signal transduction cascades and altering the physiology of the responding cell. This results in amplification of the synapse response between synaptic cells by remodelling the [[dendritic spines]] involved in the synapse.