Article Figures & Data
Figures
- Figure 1.
Modulation of the desensitization properties of AMPA receptors by γ4 is far more pronounced than by γ2. A, B, Representative scaled current responses of GluR1 (A) or GluR2(Q) (B) to the fast application of 3 mm glutamate, when coexpressed with either γ2 or γ4 (black traces) compared with current responses obtained in the absence of any TARP (gray traces). C, Extent of desensitization of homomeric and heteromeric AMPA receptors in the absence of TARPs and during coexpression of either γ2 or γ4. D, Desensitization time constants of homomeric and heteromeric AMPA receptors in the absence of TARPs or during coexpression of either γ2 or γ4. Bars represent means ± SEM (n = 5–30). *p < 0.05, **p < 0.01, ***p < 0.001, significantly different from control (without TARP); ++p < 0.01, +++p < 0.001, significantly different from coexpression of γ2. Con., Control.
- Figure 2.
The kainate efficacy of AMPA receptors is modulated by γ2 and γ4 in the same manner. A, B, Representative current responses of GluR1 (A) or GluR2(Q) (B) during application of either glutamate (Glu; 3 mm) in the presence of CTZ (300 μm) (left traces) or kainate (KA; 600 μm) (right traces), in the absence of TARPs and in coexpression with either γ2 or γ4. C, Apparent kainate efficacies of AMPA receptor complexes determined as ratios of IKA and IGlu+CTZ. Bars represent means ± SEM (n = 4–10). **p < 0.01, ***p < 0.001, significantly different from control (without TARP). Con., Control.
Tables
- Table 1.
Modulatory effects of coexpression of either γ2 or γ4 on glutamate-evoked (3 mm) peak amplitudes, desensitization properties, and the kainate efficacy of AMPA receptors
n IGlu peak (pA) τdes (ms) Extent of desensitization (%) Apparent kainate efficacy GluR1 Control 9–20 210.1 ± 55.8 6.24 ± 0.43 95.6 ± 1.2 0.04 ± 0.01 +γ2 9–30 745.5 ± 141.7 8.55 ± 0.31 92.6 ± 0.8 0.84 ± 0.08 +γ4 7–22 925.8 ± 160.2 19.68 ± 1.33 66.1 ± 4.7 0.75 ± 0.20 GluR2(Q) Control 7–8 249.8 ± 34.9 11.44 ± 0.78 86.1 ± 2.5 0.04 ± 0.01 +γ2 6–17 625.8 ± 90.8 16.84 ± 0.92 57.4 ± 3.7 0.60 ± 0.07 +γ4 8–14 468.0 ± 90.5 28.44 ± 3.10 36.4 ± 5.5 0.49 ± 0.11 GluR3 Control 5–7 47.2 ± 6.6 6.20 ± 0.75 98.6 ± 1.3 0.03 ± 0.01 +γ2 6–8 108.5 ± 24.6 11.20 ± 1.10 87.9 ± 3.2 0.92 ± 0.12 +γ4 4–5 93.0 ± 28.9 32.88 ± 2.92 43.8 ± 6.0 0.77 ± 0.06 GluR4 Control 8–10 458.5 ± 188.0 7.98 ± 0.56 89.5 ± 1.9 0.04 ± 0.01 +γ2 5–10 873.2 ± 213.7 14.58 ± 1.32 78.5 ± 4.1 0.80 ± 0.06 +γ4 9–12 658.0 ± 149.0 28.67 ± 2.67 50.4 ± 7.2 0.69 ± 0.06 GluR1/GluR2(R) Control 8–10 250.0 ± 20.4 11.42 ± 0.63 86.0 ± 3.5 0.15 ± 0.04 +γ2 6 276.5 ± 32.0 18.70 ± 1.53 62.2 ± 4.8 0.80 ± 0.05 +γ4 5 390.5 ± 60.7 33.38 ± 1.53 32.3 ± 4.2 0.77 ± 0.12 -
Apparent kainate efficacy: (IKA/IGlu+CTZ) with KA at 600 μ m, Glu at 3 mm, and CTZ at 300 μ m. Extent of desensitization (%): (1 − IGlu steady-state/IGlu peak) × 100, with Glu at 3 mm. Control, Without TARP.
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Supplemental Data
Files in this Data Supplement:
- supplemental material - Supplemental Figure 1
- supplemental material - Supplemental Text
