Virally transduced or transgenic rodent and non-human primate neural and peripheral tissues
control mechanism
Systemic or local dosing of synthetic actuator ligands (clozapine-N-oxide, deschloroclozapine) at mutated muscarinic GPCRs
pioneer
Bryan L. Roth and colleagues (directed molecular evolution of human muscarinic receptors, 2007)
Core Principles & Analysis
Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) are engineered G-protein-coupled receptors mutated in their orthosteric binding pocket so they no longer respond to endogenous acetylcholine but are potently activated by synthetic small molecules.
The excitatory DREADD hM3Dq couples to Gq signaling to mobilize intracellular Ca²⁺ and increase neuronal firing, whereas the inhibitory DREADD hM4Di couples to Gi/o signaling to activate GIRK potassium channels and silence synaptic release.
Unlike optogenetics, which requires implanted fiber optics for millisecond light delivery, chemogenetic DREADDs modulate widespread or deep brain populations non-invasively over minutes to hours after systemic actuator dosing.