Designer receptor exclusively activated by designer drug (DREADD)

Designer receptors exclusively activated by designer drugs (DREADDs) are genetically engineered G protein-coupled receptors that have been modified so they no longer respond to their natural ligand but can be selectively activated by otherwise inert synthetic small molecules. The most widely used DREADDs are based on human muscarinic acetylcholine receptors and include variants coupled to different intracellular signaling proteins—Gq for activation (e.g., hM3Dq), Gi/o for inhibition (e.g., hM4Di), and less commonly Gs. These tools allow precise chemogenetic control over cell populations, especially neurons, enabling researchers to remotely modulate cellular activity with high specificity using systemically administered ligands like clozapine-N–oxide. DREADDs have revolutionized neuroscience research for dissecting neural circuits and behaviors but are primarily experimental tools rather than direct therapeutic targets at present[1][2][6].

Other names

Designer receptors exclusively activated by designer drugsDREADDsChemogenetic receptorModified muscarinic acetylcholine receptor (e.g., hM3Dq, hM4Di)RASSL (related family, but not identical)

Activation or inhibition of engineered GPCRs by synthetic ligands that do not affect endogenous receptors, leading to modulation of intracellular signaling pathways such as Gq/11-mediated calcium release or Gi/o-mediated inhibition of cAMP production[1][2][3].