Figure 3: The AP substrates INT/BCIP and NBT/BCIP have comparable sensitivities. (A) In situ hybridization of the whole-mount larval lamprey brainstem with DCC-digoxigenin antisense probe developed with AP-INT/BCIP system. Several large identifiable neurons (M1, M2, M3, I1, I3, I4, Mauthner and B cells) are stained yellow-brown. (B) Lamprey brain after sequential ethanol washes but without glycine-Tris-HCl, pH 2.2 treatment. Note that the previously observed yellow-brown color has been completely washed away. (C) Color development of the same brainstem with NBT/BCIP. Note that all the cells that stain purpleblue when visualized with NBT-BCIP previously stained yellow-brown when visualized by INT-BCIP in A.