Fluorescent Amplification of Whole Mount In Situ Localization:

Novel fluorescent substrates for peroxidase allow fluorescent amplification of whole mount RNA in situ hybridization as well as signal amplification of whole mount immunolocalization. NEN Life Science sells a kit that includes substrates for carrying out the deposition of the fluorescent substrate once a peroxidase has been localized either to the target RNA or the target epitope.

See Lance Davidson's Fluorescent In Situ Page for more details.