Furthermore, in experiments designed to understand the role of MOR-DOR heterocomplexes in MDD and anxiety, it was shown by Kabli et al. [226] that dissociation of this heterodimer by the intra-accumbal administration of an interfering peptide was able to suppress the antidepressant and anxiolytic actions induced by the DOR agonist UFP-512 (H-Dmt-Tic-NH-CH(CH2-COOH)-bid). This evidence concerns the gene OPRD1 and major depressive disorder.