Delta Opioid Receptor 3-17

G protein-coupled receptors (GPCRs) are the largest family of membrane receptors that activate intracellular signaling cascades and undergo endocytosis, recycling, or degradation upon stimulation.  The (mu) m-, delta (d) and kappa (k) opioid receptors areGPCRs of the nervous system, which control pain, stress, and addictive behaviors.  The delta opioid receptor (DOR-1) is the stereoselective receptor for enkephalins and inhibits neurotransmitter release by reducing calcium ion currents and increasing potassium ion conductance.