Ligand-gated ion channels

Ligand-gated ion channels (LGICs), also known as ionotropic receptors, are a group of transmembrane ion channels that are opened or closed in response to the binding of a chemical messenger (i.e., a ligand), such as a neurotransmitter.

Structure

The structure of LGICs is typically composed of five protein subunits symmetrically arranged around a central pore. These subunits can be the same (homomeric) or different (heteromeric). Each subunit comprises four transmembrane domains (M1, M2, M3, and M4). The M2 domain lines the pore of the ion channel and is therefore responsible for its ion selectivity.

Function

LGICs are involved in a wide variety of physiological processes, including fast synaptic transmission in the nervous system. They are distinct from other types of ion channels in that they are directly linked to receptors that can bind to ligands, which can cause an immediate change in the permeability of the cells to ions.

Types

There are numerous types of LGICs, including:

• Cys-loop receptors
• Glutamate receptors
• ATP-gated channels
• Adenosine receptors
• GABA receptors
• Glycine receptors

Clinical significance

LGICs are the target of various pharmacological agents such as anesthetics, anticonvulsants, sedatives, and antidepressants.

See also

• Voltage-gated ion channel
• Receptor (biochemistry)
• Signal transduction
• Cell membrane

Ligand-gated ion channels Resources
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