Table 1.

Effect of Mg2+o on memantine and ketamine IC50s at −66 mV

Drug[Mg2+o ] (mm)NMDAR subtype
NR1/2ANR1/2BNR1/2CNR1/2D
Exp IC50Model IC50Exp IC50Model IC50Ratio 2A/2BExp IC50Model IC50Ratio 2A/2CExp IC50Model IC50Ratio 2A/2D
Memantine00.80 ± 0.070.57 ± 0.091.400.52 ± 0.021.540.54 ± 0.061.48
113.4 ± 1.316.510.4 ± 0.411.81.291.61 ± 0.063.368.321.76 ± 0.063.497.61
Ketamine00.33 ± 0.010.31 ± 0.021.060.51 ± 0.010.650.83 ± 0.020.40
15.35 ± 0.346.825.08 ± 0.026.411.051.18 ± 0.043.304.532.95 ± 0.025.371.81
  • All IC50 values are in μm. Exp (Experimental) IC50s (IC50 values measured by fitting concentration-inhibition curves; see Materials and Methods) are given as mean ± SE (estimated during nonlinear curve fitting by Origin) and are based on measurements from 3–4 cells for each condition. For information on Model IC50 values, see supplemental material (available at www.jneurosci.org). Each Ratio is the IC50 for NR1/2A receptors divided by the IC50 for the indicated NMDAR subtype.