11. Studies on the mechanisms and action of taurine as an osmoeffector in brain cells

Taurine has long been known as an osmolyte for intertidal invertebrates which regulate their volume during daily osmotic perturbations caused by the ebb and flood of the sea (Pierce 1982; Gilles 1987; Chamberlin and Strange 1989). However, comprehensive demonstration of taurine’s role as an osmolyte in the mammalian brain would wait until the experiments of Trachtman in 1988 and later Bedford, Lien and Verbalis in the early mid 1990s (Trachtman et al. 1988; Lien et al. 1990; Verbalis and Gullans 1991; Bedford and Leader 1993). While the mammalian brain does not experience the fluctuations in extracellular osmolality that an invertebrate may face during daily changes in sea level, several aspects of brain anatomy and metabolism render volume regulation a high priority for homeostasis of this tissue. The mammalian brain parenchyma is separated from fluid in the blood stream by a relatively water and solute impermeable blood-brain barrier. The high transport rate of glucose and other metabolic substances across this