Rubiscolin-6, a σ-opioid peptide from spinach RuBisCo, exerts antidepressant-like effect in restraint-stressed mice

Abstract

Rubiscolin-6 (Tyr-Pro-Leu-Asp-Leu-Phe) is produced by a pepsin digest of spinach d-ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) and known to act as an agonist on σ-opioid receptor. Here, we showed that administration of rubiscolin-6 reduced immobility time in the tail suspension test in restraint-stressed mice without effect on locomotor activity. The antidepressant-like effect of rubiscolin-6 was blocked by a σ-opioid receptor antagonist, naltrindole. These results indicate that rubiscolin-6 exerts antidepressantlike effect through activation of σ-opioid receptor.