Nissl body

Nissl Body

A Nissl body is a large granular body found in neurons. These bodies are essentially rough endoplasmic reticulum with rosettes of free ribosomes, and are the site of protein synthesis. Named after German psychiatrist and neuropathologist Franz Nissl, Nissl bodies are unique to neurons and are a crucial component of the cell's machinery.

History

The Nissl bodies were first identified by Franz Nissl in the late 19th century. Nissl used a staining technique with basic aniline dyes, known as Nissl staining, to visualize these structures. This technique is still used today in neuropathology to identify changes in the distribution of Nissl bodies in neurons.

Structure and Function

Nissl bodies are composed of rough endoplasmic reticulum and free ribosomes. The rough endoplasmic reticulum is responsible for protein synthesis, while the ribosomes are the site of translation, the process of producing proteins from mRNA.

Nissl bodies are found throughout the cytoplasm of neurons, but are absent from the axon. This is because the axon is the site of rapid signal transmission, and the presence of Nissl bodies could potentially interfere with this process.

Clinical Significance

Changes in the distribution or appearance of Nissl bodies can indicate neuronal damage or disease. For example, in response to injury, neurons may undergo chromatolysis, a process in which Nissl bodies disperse throughout the neuron. This is thought to be a response to increased demand for protein synthesis to repair the damaged neuron.

See Also

• Neuron
• Endoplasmic reticulum
• Ribosome
• Franz Nissl
• Nissl staining
• Chromatolysis