Ionotropic glutamate receptor

PDB 1s50 EBI

Ionotropic glutamate receptor

Ionotropic glutamate receptors are a type of glutamate receptor that are ligand-gated ion channels. These receptors are critical for synaptic transmission and play a key role in the central nervous system (CNS). They are activated by the neurotransmitter glutamate, which is the primary excitatory neurotransmitter in the CNS.

Types of Ionotropic Glutamate Receptors

Ionotropic glutamate receptors are classified into three main types based on their pharmacological properties and the specific agonists that activate them:

• AMPA receptors (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors)
• Kainate receptors
• NMDA receptors (N-methyl-D-aspartate receptors)

AMPA Receptors

AMPA receptors are responsible for fast synaptic transmission in the CNS. They are permeable to sodium (Na+) and potassium (K+) ions and, in some cases, to calcium (Ca2+) ions. These receptors are composed of four subunits, which can combine in different ways to form functional receptors.

Kainate Receptors

Kainate receptors are less well understood than AMPA and NMDA receptors. They are involved in both excitatory and modulatory roles in the CNS. Like AMPA receptors, they are permeable to Na+ and K+ ions.

NMDA Receptors

NMDA receptors are unique in that they require both glutamate binding and membrane depolarization to become activated. They are permeable to Na+, K+, and Ca2+ ions. NMDA receptors play a crucial role in synaptic plasticity, which is essential for learning and memory.

Function

Ionotropic glutamate receptors mediate rapid excitatory synaptic transmission. When glutamate binds to these receptors, they undergo a conformational change that opens the ion channel, allowing ions to flow across the cell membrane. This ion flow generates an excitatory postsynaptic potential (EPSP), which can lead to the generation of an action potential if the EPSP is strong enough.

Clinical Significance

Dysfunction of ionotropic glutamate receptors is implicated in various neurological disorders, including Alzheimer's disease, Parkinson's disease, epilepsy, and ischemic stroke. Overactivation of these receptors can lead to excitotoxicity, a process that causes neuronal injury and death.

Related Pages

• Glutamate receptor
• Synaptic transmission
• Central nervous system
• Neurotransmitter
• Excitatory postsynaptic potential
• Synaptic plasticity
• Excitotoxicity

See Also

• Metabotropic glutamate receptor
• Neurotransmission
• Neuroplasticity