ESNs exhibit sensitive and specific responses to BoNTs. A. Log:lin plot calculated from densitometric measurements of SNARE cleavage after a 24 h exposure to 0–17,800 pM BoNT/B, BoNT/C, BoNT/D, BoNT/F and BoNT/G (n ≥ 5 for all time points). B. Fractional cleavage of SNAP-25 after exposing ESNs to 6.7 or 67 pM BoNT/A under depolarizing (K+) or basal (BEB or NB+B27) conditions (n = 5). Error bars indicate standard error.