Ionotropic receptor (also ligand gated ion channel) are a subclass of transmembrane receptors. Their ion channel is regulated by a neurotransmitter ligand and is usually very selective to one or more ions like Na²⁺, Na⁺, Ca²⁺, or Cl^-. Ionotropic receptors located at synapses convert the chemical signal of presynaptically released neurotransmitter directly and very quickly into a postsynaptic electrical signal. This is in contrast to the metabotropic receptors which are not ion channels and signal slowly through complex intracellular second messenger cascades. Many ionotropic receptors are additionally modulated by allosteric ligands, by channel blockers, ions, or the membrane potential.

See also:

• Receptor (biochemistry)
• NMDA receptor
• AMPA receptor
• Kainate receptor
• Nicotinic acetylcholine receptor
• Glycine receptor
• GABA_A receptor
• 5-HT₃ receptor
• Glycine receptor