Figure 2.

PMP inhibition of recombinant homomeric and heteromeric KARs. A, Representative currents from recombinant homomeric and heteromeric KARs. Currents were evoked by glutamate for 100 ms either alone (black lines) or in the presence of PMP (10 µm, colored lines). Top, The gray bar denotes glutamate application. The current amplitudes of heteromeric GluK1/GluK5 and GluK2/GluK5 KARs are markedly decreased by PMP compared with those of homomeric GluK1 or GluK2 KARs. PMP did not inhibit either GluK3 or GluK3/GluK5 KARs to a substantial degree. B, Normalized mean amplitudes of currents evoked from recombinant homomeric and heteromeric KARs at a range of PMP concentrations were best fit with logistic curves with variable IC₅₀ and Hill slopes. Homomeric GluA4(i) AMPARs are shown for comparison to demonstrate that GluK2/GluK5 KARs are inhibited in the same concentration range as AMPARs. IC₅₀ values, 95% confidence intervals, and statistical analyses are shown in Table 1.