Subcommissural organ

Subcommissural Organ

The Subcommissural Organ (SCO) is a small glandular structure found in the brain of most vertebrates, including humans. It is located in the third ventricle, at the junction of the third ventricle and the cerebral aqueduct. The SCO is involved in the production of a glycoprotein substance known as Reissner's fiber.

Etymology

The term "subcommissural" is derived from the Latin words "sub" meaning under, and "commissura" meaning a joining together. This refers to the organ's location beneath the posterior commissure, a band of white matter in the brain that connects the two cerebral hemispheres.

Structure and Function

The Subcommissural Organ is composed of secretory ependymal cells that produce a complex glycoprotein known as SCO-spondin. This substance is secreted into the cerebrospinal fluid (CSF) where it forms a long, thread-like structure known as Reissner's fiber. The exact function of Reissner's fiber is not fully understood, but it is believed to play a role in the circulation of CSF.

In addition to producing SCO-spondin, the Subcommissural Organ also has a role in the regulation of the blood-brain barrier. It is thought to influence the permeability of the barrier, thereby controlling the exchange of substances between the blood and the brain.

Clinical Significance

Abnormalities in the Subcommissural Organ have been associated with a number of neurological disorders. For example, a decrease in the production of SCO-spondin has been observed in patients with hydrocephalus, a condition characterized by an accumulation of CSF in the brain. This suggests that the SCO may play a role in the pathogenesis of this disorder.

See Also

• Ependyma
• Cerebrospinal fluid
• Hydrocephalus

References

Subcommissural organ Resources
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