Ratiometric imaging of fresh rat hippocampal slice treated with H
. (A) The reaction between PN1 and H2O2 produced AN1 as the only major fluorescent product. (B) A hippocampal slice labeled with PN1. (C) Fluorescence spectra responses of 3 μM PN1 to 1 mM H2O2. Spectra were acquired at 0, 10, 20, 30, 40, 50, 60, and 120 min after H2O2 was added. (D) A hippocampal slice labeled with PN1 after pretreated with H2O2. Scale bars: 30 μm. The figures were adapted from ref.  with permission.