BCSFB

In addition, the epithelial cells of the choroid plexus facing the cerebrospinal fluid (CSF) constitute the blood-cerebrospinal fluid barrier (BCSFB). The BCSFB is also a significant area for exchange between the blood and the CSF. In rats the total calculated surface area of the choroid plexus is about 33% of that of the BBB [2]. In humans, based on the relative mass of the choroid plexus in comparison with the brain, the relative surface area of the choroid plexus may be in the region of 10% of that of the BBB. The CSF is secreted across the choroid plexus epithelial cells into the brain ventricular system [3] the remainder of the brain extracellular fluid (ECF) and the interstitial fluid (ISF) are secreted at the capillaries of the BBB themselves [4]. The ratio of fluid production from these sites is 40% 60%, respectively [5],... 

Fig. 2 Possible transportation routes of drugs after nasal administration. MCC = mucociliary clearance BBB = blood-brain barrier BCSFB = blood SF barrier.

MRP4 ABCC4 13q32 NM 005845 1325 12 Liver, kidney, and brain Basal (liver, BCSFB), apical (kidney, BBB) E217pG, cAMP, cGMP, 6-mercaptopurine, folate, prostaglandins, and so on... 

Both the BBB and the BCSFB actively regulate the type and concentration of molecules transported to and from the extracellular fluid, CSF, and intracellular fluid [21]. Because of its large surface area ( 20ni /1.3 kg brain) and the short diffusion distance between neurons and capillaries (8-20 pm), the endothelium plays a predominant role in regulating the brain environment [1]. The BCSFB also contributes to this process besides playing other roles [22]. It was proposed... 

Passage of drugs into the CSF is controlled by the BCSFB. This barrier is created by ependymal cells of the choroid plexus, which function as an active transport system similar to the renal tubular epithelial cells. The inflammatory process associated with meningitis inhibits the active transport system of the choroid plexus. As in the active transport system in the kidney, the secretion of substances out of the choroid plexus also can be inhibited by the administration of probenecid. ... 

AIDS acquired immunodeficiency syndrome BBB blood-brain barrier BCSFB blood-cerebrospinal fluid barrier CBF cerebral blood flow... 

There are two barrier systems in the normal adult brain the blood-brain barrier (BBB) and the blood cerebrospinal fluid barrier (BCSFB). The BBB is composed of three cell types, all of which play an important role in BBB integrity and regulation endothelial cells of the cerebral vasculature, astrocytes, and pericytes (Fig. 1). Pericytes of BBB localize to the capillary basement membrane, sandwiched next to endothelial vessel cells by astrocytic end feet, which form very extensive and intimate bundles around both pericytes and endothelial vessel cells (Fig. 1). Specific characteristics of the BBB are believed to be maintained and induced by the astrocytic processes [28 30]. The endothelial cells of the cerebral vasculature differ from their counterparts in peripheral systems in that they lack fenestrations [31 33], demonstrate little to no... 

The BCSFB constitutes an additional compartment in the CNS which drugs must traverse. The BCSFB is comprised of the choroid plexus and arachnoid membranes which consist of choroid and arachnoid epithelium, respectively, as their major cell constituents. These structures interface with nearly all major... 

It is well-established that Pb accumulates in the choroid plexus of himians as well as animals, suggesting that the choroid plexus is a primary target for Pb-induced neurotoxicity Behl et al. (2009) demonstrated that exposure to Pb results in a significantly increased accumulation of intracellular amyloid-p (APi o) hi rat choroid plexus tissues in mvo and in immortalized choroidal epithelial Z310 cells in intro. Several mechanisms may lead to an increased Ap level at the BCSFB a diminished expulsion of Ap molecules from the plexus cells to the extracellular milieu an increased uptake of Ap from the CSF, blood, or both an increased synthesis of Ap and/or a reduced metabolism or degradation of Ap. Pb-induced inhibition of the production of LRPl (a key intracellular Ap transport protein in the choroid plexus) may be responsible for the accmnulation of Ap, and may be a major risk factor for AD. 

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