A stable intraventricular milieu is crucial for maintaining normal neuronal function. The choroid plexus epithelium produces the cerebrospinal fluid and in doing so influences the chemical composition of the interstitial fluid of the brain. Here, we review the molecular pathways involved in transport of the electrolytes Na, K, Cl, and HCO3 across the choroid plexus epithelium.
The human brain is a delicate organ that is surrounded by the rigid skull. The effective weight of the brain is reduced from 1,500 to 50 g by being submerged in the cerebrospinal fluid (CSF). This helps reduce the risk of mechanical injury to the brain parenchyma and cerebral blood vessels (51). The CSF is constantly secreted and thus displaces older fluid, which drains into the systemic circulation via the dural sinuses. This creates a flow of fluid through the ventricular system, which is important in maintaining a stable environment within the brain. The flow of CSF also assists in the removal of waste products from the central nervous system, e.g., excess neurotransmitters (43), debris from the surface lining epithelium, bacteria, and viruses (22).
