Figure 7
Astrocytic SLC7A10 mediates glycine enrichment in glycinergic inhibitory neurons.
Either via direct supply of glycine, or through supply of biosynthetic precursors such as L-serine, astrocytic SLC7A10 mediates the cytoplasmic enrichment of glycine in glycinergic inhibitory neurons required to maintain adequate loading/quantal content of glycinergic synaptic vesicles. This model predicts that Slc7a10-null mice are unable to supply or recycle glycine (or glycine precursors) from astrocytes to glycinergic neurons; insufficient cytoplasmic concentration of glycine within glycinergic neurons leads to decreased vesicular glycine quanta, as reflected in diminished glycinergic mIPSC amplitudes and a hyperekplexia-like phenotype. Our observation that mice heterozygous for Slc7a10 show mIPSC amplitudes intermediate to those of Slc7a10-null mice and wild type mice is consistent with a concentration-dependent model.
