Such membrane-associated transport systems are especially important in epithelia which function to maintain total body homeostasis by selectively excreting certain substances and reabsorbing others. The choroid plexus is an epithelia dedicated to maintaining homeostasis for the brain in much the same way that the kidney does for the total body. However, the mechanisms by which the choroid plexus accomplishes this homeostatic function are poorly understood. In particular, age-related characteristics of transport via the choroid plexus have received little attention.
Taurine provides an ideal focus for three reasons.
First, it is crucial for normal development of the central nervous system. Taurine depletion during fetal and early postnatal life is associated with severe neurological deficits. Second, data suggest that systems in the choroid plexus for the transport of other amino acids change as a function of age. Therefore, it is reasonable to propose that transport systems for taurine in choroid plexus may also undergo developmental changes. We are just completing an in vivo study in rats measuring the clearance of taurine using a stereotactic technique.