A procedure for the simultaneous demonstration of neurosecretory and mucosubstances in tissue sections

Many well known histochemical techniques have been employed to study the neurosecretory products in invertebrates and vertebrates. Among these aldehyde-fuchsin (AF) has been one of the two specific stains to demonstrate the presence of neurosecretory cells. Various counterstains have been employed with AF. However, AF is also useful in demonstrating the presence of mucosubstances or elastin. A method is described here for a simultaneous demonstration of neurosecretory substances (NSS) and mucosubstances (MS) by mercurochrome counterstaining. For this method sections of material fixed in methanol-formaldehyde-acetic acid (MFA) or alcoholic Bouin's or Susa were oxidized in 0.3% permanganate with 0.3 ml concentrated H2SO4 for 1 to 2 minutes, decolorized in 1% oxalic acid, stained in 0.5% aqueous basic fuchsin containing 1 ml concentrated HCl and 1 ml paraldehyde for 10 min and counterstained with 0.5% aqueous mercurochrome. After mercurochrome counterstaining the characteristic AF staining (purple colour) of NSS is dramatically swamped (becoming brick red) but the purple developed by MS remains unaltered in vertebrate and invertebrate material. Eosin or other counterstains do not behave in this way.