Figure 4.

Specificity of increases in Glu uptake. (A) The increase in synaptosomal Glu uptake produced by 500 μM 5-HT (n = 12) was not observed when sodium was removed from the extracellular media (n = 6). Synaptosomal uptake of Leu was not affected by 5-HT in vivo (n = 4). Synaptosomal Gln uptake was significantly increased by 5-HT in vivo (n = 6). (B) Gln uptake was inhibited by excess Gln, but not by excess Glu, indicating that Gln uptake was through a Gln transporter. (C) Glu uptake was inhibited by excess Glu, but not by excess Gln, indicating that Glu uptake was through a Glu transporter.