In cellular neuroscience, Nissl bodies (also called Nissl granules, Nissl substance or tigroid substance) are discrete granular structures in neurons that consist of rough endoplasmic reticulum, a collection of parallel, membrane-bound cisternae studded with ribosomes on the cytosolic surface of the membranes. [1] Nissl bodies were named after Franz Nissl, a German neuropathologist who invented the staining method bearing his name ( Nissl staining). [2] [3] The term "Nissl bodies" generally refers to discrete clumps of rough endoplasmic reticulum and free ribosomes in nerve cells. Masses of rough endoplasmic reticulum also occur in some non-neuronal cells, where they are referred to as ergastoplasm, basophilic bodies, [1] or chromophilic substance. [4] While these organelles differ in some ways from Nissl bodies in neurons, [5] large amounts of rough endoplasmic reticulum are generally linked to the copious production of proteins. [1]
"Nissl stains" refers to various basic dyes that selectively label negatively charged molecules such as DNA and RNA. Because ribosomes are rich in ribosomal RNA, they are strongly basophilic ("base-loving"). The dense accumulation of membrane-bound and free ribosomes in Nissl bodies results in their intense coloration by Nissl stains, allowing them to be seen with a light microscope. [1]
Nissl bodies occur in the somata and dendrites of neurons, though not in the axon or axon hillock. [6] They vary in size, shape, and intracellular location; they are most conspicuous in the motor neurons of the spinal cord and brainstem, where they appear as large, blocky assemblies. [5] In other neurons, they may be smaller, and in some (such as the granule neurons of the cerebellar cortex) very little rough endoplasmic reticulum is present. [5] The pattern of coloration with Nissl stains once was used to classify neurons. [5] For various reasons, this practice has largely ceased, but specific neuronal types do manifest characteristic types of Nissl bodies. [5]
The functions of Nissl bodies are thought to be the same as those of the rough endoplasmic reticulum in general, primarily the synthesis and segregation of proteins. [1] [2] Similar to the ergastoplasm of glandular cells, Nissl bodies are the main site of protein synthesis in the neuronal cytoplasm. [5] The ultrastructure of Nissl bodies suggests they are primarily concerned with the synthesis of proteins for intracellular use. [7]
Nissl bodies show changes under various physiological conditions and in pathological conditions such as axonotmesis, during which they may dissolve and largely disappear ( chromatolysis). If the neuron is successful in repairing the damage, the Nissl bodies gradually reappear and return to their characteristic distribution within the cell. [5]
In cellular neuroscience, Nissl bodies (also called Nissl granules, Nissl substance or tigroid substance) are discrete granular structures in neurons that consist of rough endoplasmic reticulum, a collection of parallel, membrane-bound cisternae studded with ribosomes on the cytosolic surface of the membranes. [1] Nissl bodies were named after Franz Nissl, a German neuropathologist who invented the staining method bearing his name ( Nissl staining). [2] [3] The term "Nissl bodies" generally refers to discrete clumps of rough endoplasmic reticulum and free ribosomes in nerve cells. Masses of rough endoplasmic reticulum also occur in some non-neuronal cells, where they are referred to as ergastoplasm, basophilic bodies, [1] or chromophilic substance. [4] While these organelles differ in some ways from Nissl bodies in neurons, [5] large amounts of rough endoplasmic reticulum are generally linked to the copious production of proteins. [1]
"Nissl stains" refers to various basic dyes that selectively label negatively charged molecules such as DNA and RNA. Because ribosomes are rich in ribosomal RNA, they are strongly basophilic ("base-loving"). The dense accumulation of membrane-bound and free ribosomes in Nissl bodies results in their intense coloration by Nissl stains, allowing them to be seen with a light microscope. [1]
Nissl bodies occur in the somata and dendrites of neurons, though not in the axon or axon hillock. [6] They vary in size, shape, and intracellular location; they are most conspicuous in the motor neurons of the spinal cord and brainstem, where they appear as large, blocky assemblies. [5] In other neurons, they may be smaller, and in some (such as the granule neurons of the cerebellar cortex) very little rough endoplasmic reticulum is present. [5] The pattern of coloration with Nissl stains once was used to classify neurons. [5] For various reasons, this practice has largely ceased, but specific neuronal types do manifest characteristic types of Nissl bodies. [5]
The functions of Nissl bodies are thought to be the same as those of the rough endoplasmic reticulum in general, primarily the synthesis and segregation of proteins. [1] [2] Similar to the ergastoplasm of glandular cells, Nissl bodies are the main site of protein synthesis in the neuronal cytoplasm. [5] The ultrastructure of Nissl bodies suggests they are primarily concerned with the synthesis of proteins for intracellular use. [7]
Nissl bodies show changes under various physiological conditions and in pathological conditions such as axonotmesis, during which they may dissolve and largely disappear ( chromatolysis). If the neuron is successful in repairing the damage, the Nissl bodies gradually reappear and return to their characteristic distribution within the cell. [5]