Franz Nissl



Franz Nissl (September 9, 1860 – August 11, 1919) was a German neuropathologist. Born in Bavaria, he did his medical studies in Munich where he became interested in the pathology of cortical neurons. He is best known for developing a histological stain which allowed for selective visualization of neuronal cell bodies throughout the brain, ushering a new era in neurocytology and neuropathology. He also did important work in psychiatry correlating changes in glial cells, blood vessels, and brain tissue in general with mental illness. He also worked with and was friends with Alois Alzheimer. Toward the end of his life he studied the nature of the connections between the cerebral cortex and the thalamus.

Named Histology Concepts
The Nissl method uses basic aniline to stain RNA blue, and is used to highlight important structural features of neurons. The Nissl substance (rough endoplasmic reticulum) appears dark blue due to the staining of ribosomal RNA, giving the cytoplasm a mottled appearance. Individual granules of extranuclear RNA are named Nissl granules (ribosomes). DNA present in the nucleus stains a similar color.