Figure 6.

NMDA receptors with intrasubunit GluN1 or GluN2A cross-links display largely symmetrical changes in multiple open- and closed-time components. (A, left) Mean fold change (±SEM) in duration of open-time components as determined by MIL fitting of single-channel recordings (see Materials and methods). Although single-channel records (in the cell-attached configuration) comprised two to four open-time components arising from modal gating behavior of NMDA receptors (Popescu and Auerbach, 2003), they were combined for simplicity into aggregates of two states, one short duration (for N1/N2A, 0.12 ± 0.01 ms) and one long duration (for N1/N2A, 8.71 ± 0.9 ms) (see Table II). (Right) Mean relative areas (±SEM) of the open-time components. (B, top) Mean fold change in duration (±SEM) of closed-time components as determined by MIL fitting of single-channel recordings. For WT GluN1/GluN2A, the time constants were (ms): τ₁ 0.14 ± 0.01, τ₂ 1.03 ± 0.13, τ₃ 4.16 ± 0.4, τ₄ 26.9 ± 5.6, and τ₅ 1,789 ± 366 (see Table II). (Bottom) Mean relative areas (±SEM) of the closed-time components. Significant differences (P < 0.05) relative to WT and between GluN1(C,C)/GluN2A and GluN1/GluN2A(C,C) are indicated with filled bars and asterisks, respectively.