NR2ANR2D

NR2ANR2D is a designation used in neurobiology to describe NMDA-type glutamate receptors that incorporate both NR2A and NR2D subunits, typically assembled with NR1. In practice, these receptors are often discussed as tri-heteromeric channels containing NR1, NR2A, and NR2D, though co-expression of NR2A and NR2D can yield receptors with mixed subunit compositions and properties.

NMDA receptors are ligand-gated ion channels that require glutamate and a co-agonist (usually glycine or D-serine) to activate. The NR2A and NR2D subunits confer distinct kinetic and pharmacological features, with NR2D-containing receptors generally showing slower deactivation and higher glutamate affinity than NR2A-containing receptors. When NR2A and NR2D are co-assembled, the resulting NR1/NR2A/NR2D receptors tend to exhibit intermediate decay kinetics and a pharmacological profile distinct from receptors containing only NR2A or only NR2D. The exact properties can depend on subunit stoichiometry and the neuronal context.

Distribution and function: NR2A and NR2D subunits are expressed in overlapping but heterogeneous patterns across brain regions, including cortex and hippocampus. NR2D expression is relatively higher during early development, while NR2A becomes more prominent later, shaping the maturation of NMDA receptor signaling. Receptors containing both NR2A and NR2D contribute to synaptic transmission and plasticity and are studied for their potential roles in development, learning, and certain neuropsychiatric conditions.

Nomenclature note: NR2ANR2D is not a separate gene or protein class but a shorthand used in some studies to denote NMDA receptors that include both NR2A and NR2D subunits.