Application of α7pep2 peptide blocked choline induced upregulation of mEPSC of LTP in hippocampal primary culture. (A) Examples of continuous recordings from individual neurons 40 minute after intracellular application of α7pep2 peptide (10 µM) with/without the presence of choline (1 mM, 8 min). (B) Single events taken from the basal and choline traces after intracellular application of α7pep2 peptide, showing that choline application failed to increase the amplitude of mEPSCs. (C) Cumulative fraction plots for mEPSCs inter-event intervals and amplitudes obtained 5 minutes before (Basal) and 30 minutes after choline (8 min, 1 mM) with the presence of α7pep2 peptide intracellularly. (D) 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 α 7pep2 (basal: 24.2+/-2.0; choline: 25.1 +/-2.3 pA, n = 6, p > 0.05, paired t-test).