Yokukansan, a Traditional Japanese Medicine, Enhances the Glutamate Transporter GLT-1 Function in Cultured Rat Cortical Astrocytes

Figure 1

Effect of TA treatments and Yokukansan (YKS) on glutamate uptake in cultured rat cortical astrocytes. Astrocytes were exposed for 72 h in culture medium supplemented with or without 50 ng/mL TNF-α and 150 μM dBcAMP (TA). The cultures were treated with or without 500 μg/mL YKS. One day before measuring glutamate uptake, the content was replaced with serum-free medium. The glutamate uptake ability in each sample was evaluated based on the glutamate concentration measured in the culture supernatant collected from the culture medium 3 h after adding 100 μM glutamate (a). Here, the total glutamate uptake (total) is represented as the difference between the 100 μM glutamate added and the glutamate concentration in the culture medium. The difference between the glutamate concentration in the medium containing DHK (DHK (+)) and the glutamate concentration in the DHK-free medium (DHK (−)) signifies the GLT-1-mediated glutamate uptake, whereas the difference between the 100 μM added glutamate and DHK (+) is regarded as the GLAST-mediated glutamate uptake. (b), (c), and (d) show the total, GLT-1-mediated, and GLAST-mediated glutamate uptakes, respectively. Each column is the mean ± SEM (). Asterisks and daggers indicate a significant difference: , versus Control (0 μg/mL YKS), and versus TA (0 μg/mL YKS).

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