The delta-opioid receptor, also known as delta opioid receptor or simply delta receptor, abbreviated DOR, is an opioid receptor that has enkephalins as its endogenous ligands. Opioid receptors mediate the analgesic action and addictive properties of opioid drugs. The delta-receptor is a promising target for treatment of both drug addiction and mood-related disorders. DOR is also a good target related with Alzheimer′s Disease (AD). Agonist-induced activation of the delta-opioid receptor has been shown to augment beta - and gamma-secretase activities, which increased the production of beta -amyloid peptide (Abeta ), known to accumulate in the brain tissues of Alzheimer"s disease (AD) patients.