Ionotropic Channels: Ligand-Gated and Voltage-Gated

Types of Ionotropic Channels

• There are two primary types of ionotropic channels (ion channels) within a neuron, distinguished by their location and the 'key' required to open them.

  • First Type (Dendrites and Cell Body): Specific channels in these areas open with one type of 'key'.

  • Second Type (Axon and Axon Terminals): Other specific channels along the axon and axon terminals open with a second specific type of 'key'.

Ligand-Gated Ion Channels

• Definition: These are ionotropic channels that are opened by a specific chemical 'key' known as a ligand.

• The Ligand as a Neurotransmitter: In the context of neurons, the ligand that opens these channels is a neurotransmitter. Therefore, ligand $\Leftrightarrow$ neurotransmitter.

• Location and Activity: Ligand-gated ion channels are most active on the dendrites and cell body of a neuron. These correspond to the