Functions as a sodium-dependent amino acid transporter. Mediates the saturable, pH-sensitive and electrogenic cotransport of glutamine and sodium ions with a stoichiometry of 1:1. May also transport small zwitterionic and aliphatic amino acids with a lower affinity. May supply glutamatergic and GABAergic neurons with glutamine which is required for the synthesis of the neurotransmitters glutamate and GABA (By similarity). Inhibited by lithium, potassium, choline ions, N-methyl-D-glucamine and 2-methylamino-isobutyric acid (MeAIB). Restricted to the somatodendritic compartment of neurons. Found in the cellular processes of neurons in the developing brain. Belongs to the amino acid/polyamine transporter 2 family.