Application of α7pep2 peptide blocked choline induced upregulation of NMDA current in hippocampal primary culture. (A) The choline-induced synergistic effect is significantly inhibited by intracellular application of interfering peptides α7pep2, but not α7pep1 (10 µM) (choline/NMDA: 1202.7 ± 182.1 pA; NMDA: 910.5 ± 130.8, n = 6, p > 0.05). Cells were hold at -70 mV, 20 mM bicuculline, 1 mM strychnine, 0.5 μM TTX, 1 mM glycine were included in the extracellular solution. (B) Amplitude histogram summarizes data from groups of individual neurons treated with glycine (200 μM; 3 min) in the absence or presence of choline (1 mM) with the intracellular application of α7pep1, α7pep2 peptide respectively. Responses obtained 30 min after glycine treatment (basal) and 30 min after choline treatment (choline). α7pep1 peptide did not block the enhancing effect of choline on the mEPSC amplitude (basal: 25.2 +/-2.1 pA; choline: 28.4+/-2.4 pA, n = 4, *p < 0.01, paired t-test) while choline failed to upregulate mEPSC amplitude with the presence of α7pep2 (basal: 24.2+/-2.0; choline: 25.1 +/-2.3 pA, n = 6, p > 0.05, paired t-test).