Permeation of calcium through glutamate receptor channels

Excitatory neurotransmission is mainly mediated by cationic channels activated by glutamate in the mammalian central nervous system (CNS). Molecular cloning and expression studies have revealed that the subtype diversity of the glutamate receptor channel is much larger than expected from pharmacological studies. Among various types of glutamate receptor channels, the NMDA receptor channel is most permeable to Ca²⁺. The Ca²⁺permeability of the AMPA receptor channel depends on the subunit composition. The receptor channel lacking the edited form of GluR2 subunit has a substantial permeability to Ca²⁺. Physiological and pathological implications of the Ca²⁺inflow through these glutamate receptor channels are discussed.