Nissl body

A Nissl body (or Nissl granule or tigroid body) is a large granular body found in neurons. It was named after Franz Nissl, German neurologist (1860-1919).

Nissl bodies can be demonstrated by a method of selective staining developed by Nissl (Nissl staining), using an aniline stain to label extranuclear RNA granules. RNA stains blue with this method due to its basophilic (lat. "base-loving") properties.

These granules are rough endoplasmic reticulum (with ribosomes) and are the site of protein synthesis.

Nissl bodies show changes under various physiological conditions and in pathological conditions they may dissolve and disappear (karyolysis).