Which stain is used to identify chromatolysis in neurons?

• A. Cresyl Echt Violet
• B. Bielschowsky
• C. Cajal
• D. Holmes

Answer: (A)

Chromatolysis is the loss or dispersion of the Nissl substance, which are the basophilic granules of rough endoplasmic reticulum and ribosomes in the neuron’s soma. A Nissl stain like Cresyl Echt Violet binds to the RNA in these granules, making them stand out as distinct blue-purple bodies in healthy neurons. When chromatolysis occurs, these Nissl bodies break down and spread out or fade, so the staining pattern becomes disrupted and the cytoplasm around the nucleus may look clearer. Cresyl Echt Violet is specifically suited to reveal these changes because it highlights the Nissl material directly.

Other stains emphasize different neuronal features rather than the Nissl substance. Bielschowsky stain highlights axons and neurofibrillary changes; Cajal staining (Golgi-type methods) reveals overall neuron morphology but not the specific state of the Nissl bodies; Holmes stain also targets different tissue components and is not focused on Nissl substance.