The function of SLC38A1 (solute carrier family 38 member 1, Ensembl gene identifier ENSG00000111371) is as follows. Symporter that cotransports short-chain neutral amino acids and sodium ions from the extracellular to the intracellular side of the cell membrane (PubMed:10891391, PubMed:20599747). The transport is elctrogenic, pH dependent and driven by the Na(+) electrochemical gradient (PubMed:10891391). Participates in the astroglia-derived glutamine transport into GABAergic interneurons for neurotransmitter GABA de novo synthesis (By similarity). May also contributes to amino acid transport in placental trophoblasts (PubMed:20599747). Also regulates synaptic plasticity (PubMed:12388062). {ECO:0000250|UniProtKB:Q8K2P7, ECO:0000250|UniProtKB:Q9JM15, ECO:0000269|PubMed:10891391, ECO:0000269|PubMed:12388062, ECO:0000269|PubMed:20599747}.