Neuron-specific, H(+)-coupled oligopeptide transporter with broad specificity towards di- and tripeptides in a Na(+) and Cl(-)-independent manner. Shows H(+) channel activity in the absence of peptide substrates. Expressed in the AVA interneuron. Expression is detected as early as the larval L1 stage and continues into the adult stage. Belongs to the major facilitator superfamily. Proton-dependent oligopeptide transporter (POT/PTR) (TC 2.A.17) family.