Description_x000D_ General description_x000D_ Clozapine N-oxide hydrochloride is a water soluble form of Clozapine N-oxide (CNO) (Sigma cat# C0832). CNO is a pharmacologically inert metabolite of the atypical anti-psychotic drug clozapine. CNO is a ligand for the engineered Gq protein coupled receptors (GPCRs) in the chemogenetic Designer Receptors Exclusively Activated by Designer Drug (DREADD). The typical use of DREADD is testing, enhancing neuronal firing and activating Gq signaling in neuronal and non-neuronal cells._x000D_ The selective targeting of DREADD systems to cell population can be achieved by using a cell type-specific promoter to drive DREADD expression, and the expression of this promoter can be further controlled using a recombinase-based system. DREADDs possess a low affinity for endogenous ligands and little constitutive activity, but may be activated by synthetic compounds such as CNO._x000D_ DREADD systems are activated by low nM concentrations of CNO and mobilize intracellular calcium. CNO appears to be pharmacologically and behaviorally inert in mice and rats when administered at the recommended doses (generally 0.1–3 mg/kg). CNO is commonly administrated via injection but also can be mixed into food chow or drinking water._x000D_ Other Notes_x000D_ High concentration Solutions of (40mg/ml) can be prepared from the water soluble CNO and be used in CNO applications without the use of DMSO.