TC-2559 enhances sIPSCs by activation of α4β2 subtype of nAchRs. A, Sample traces of sIPSCs recorded from a lamina II neuron in the presence of 15 μM DNQX and 2 μM DHβE before (left) and during bath application of 2 μM TC-2559 (right). Membrane potential was clamped at -70 mV. B-C, Normalized rate histogram showing the sIPSC frequency (B) and amplitude (C) before and during bath application of 2 μM TC-2559 in the presence of 2 μM DHβE (n = 12). D-E, In the presence of 2 μM DHβE, 2 μM TC-2559 had no significant effects on both the frequency (D, P = 0.6865, n = 12) and amplitude (E, P = 0.0978, n = 12) of sIPSCs (Paired t test).