Using Opioid Receptors to Expand the Chemogenetic and Optogenetic Toolbox

In this issue of Neuron, innovative new modifications to opioid receptors are used to expand the tools available to modulate neuronal activity. Vardy et al. (2015) describe a new “DREADD” chemogenetic tool based on the inhibitory κ opioid receptor (KORD) that can be used in conjunction with already-available DREADDs. Siuda et al. (2015) report the development of “opto-MOR,” a light-activatable μ opioid receptor (MOR) chimera that can be used to better understand the complexities of MOR signaling. Extending the toolset to inhibit neuronal activity in this issue of Neuron, Vardy et al. (2015) describe the development of a new “DREADD” chemogenetic tool based on the κ opioid DREADD (KORD), a mutated Gαi-coupled kappa-opioid receptor, activated by the pharmacologically inert ligand salvinorin B (SALB), and Siuda et al. (2015) create the “opto-MOR,” a Gαi-coupled, photosensitive, mu-opioid-like chimeric receptor.