Stimulation of Na+/Cl--coupled Opioid Peptide Transport System in SK-N-SH Cells by L-kyotorphin, an Endogenous Substrate for H+-coupled Peptide Transporter PEPT2

DOI Web Site Web Site 2 Citations 78 References

Bibliographic Information

Other Title
  • Stimulation of Na+/Cl−-coupled Opioid Peptide Transport System in SK-N-SH Cells by L-kyotorphin, an Endogenous Substrate for H+-coupled Peptide Transporter PEPT2

Search this article

Abstract

  We have recently identified a Na+/Cl--coupled transport system in mammalian cells for endogenous and synthetic opioid peptides. This transport system does not transport dipeptides/tripeptides, but is stimulated by these small peptides. Here we investigated the influence of L-kyotorphin (L-Tyr-L-Arg), an endogenous dipeptide with opioid activity, on this transport system. The activity of the transport system, measured in SK-N-SH cells (a human neuronal cell line) with deltorphin II as a model substrate, was stimulated ~2.5-fold by L-kyotorphin, with half-maximal stimulation occurring at ~100 μM. The stimulation was associated primarily with an increase in the affinity for deltorphin II. The stimulation caused by L-kyotorphin was stereospecific; L-Tyr-D-Arg (D-kyotorphin) had minimal effect. The influence of L-kyotorphin was observed also in a different cell line which expressed the opioid peptide transport system. While L-kyotorphin is a stimulator of opioid peptide transport, it is a transportable substrate for the H+-coupled peptide transporter PEPT2, which is expressed widely in the brain. Since the activity of the opioid peptide transport system is modulated by extracellular L-kyotorphin and since PEPT2 is an important determinant of extracellular L-kyotorphin in the brain, the expression/activity of PEPT2 may be a critical factor in the modulation of opioidergic neurotransmission in vivo.<br>

Journal

Citations (2)*help

See more

References(78)*help

See more

Keywords

Details 詳細情報について

Report a problem

Back to top