mEPSC amplitude (A), area (B), max-rise-rate (C), and decay time (D) from hippocampal neurons overexpressing Syb2 with the indicated glycine, arginine, and aspartate substitutions, and with a 101/103 double arginine substitution. Max-rise-rates were significantly reduced by two of the arginine mutations (Bonferroni test, 101R: N = 25, t = 3.00, p = 0.033, RR: N = 25, t = 3.08, p = 0.025). All groups had ≥ 20 cells. *p < 0.05.