Blood—Brain Barrier Taurine Transport during Osmotic Stress and in Focal Cerebral Ischemia

Open Access
Publisher Website
Google Scholar
Abstract
Little is known about blood to brain taurine transport despite substantial evidence suggesting a role of taurine in brain volume regulation during osmotic stress or conditions inducing cell swelling, such as ischemia. We have made measurements of the taurine influx rate constant (K1) with [3H]taurine in three conditions: raised plasma taurine concentrations induced by infusion with 50 mM taurine (10 μl/100 g/min); osmotic stress induced by i.p. injections of 1.5 M NaCl (2 ml/100 g) or distilled water (10 ml/100 g); and 4 h of middle cerebral artery occlusion (MCAo). In rats with MCAo, additional determinations were made of tissue water and taurine contents, and blood-brain barrier passive permeability with [3H]α-aminoisobutyric acid. Taurine infusion increased plasma taurine from 110 ± 63 μM (SD) to 407 ± 63 (p < 0.001) and decreased taurine K1 at the blood–brain barrier by 70% (p < 0.001), signifying saturable uptake that maintained unidirectional influx constant. Similarly, although hypo- and hyperosmol...