Chemogenetic

The term chemogenetics has been used to describe the processes by which macromolecules can be engineered to interact with previously unrecognized small molecules. Chemogenetics as a term was originally coined to describe the observed effects of mutations on chalcone isomerase activity on substrate specificities in the flowers of Dianthus caryophyllus. This Method is very similar to Optogenetics however, it uses chemically engineered molecules and ligands instead of light and light-sensitive channels known as Opsins.

In recent research projects, chemogenetics has been widely used to understand the relationship between brain activity and behavior. Prior to chemogenetics, researchers used methods such as transcranial magnetic stimulation (TMS) and deep brain stimulation(DBS) to study the relationship between neuronal activity and behavior.

Optogenetics and Chemogenetics are the more recent and popular methods used to study this relationship. Both of these methods target specific brain circuits and cell population to influence cell activity. However, they use different procedures to accomplish this task. Optogenetics uses light-sensitive channels and pumps that are virally introduced into neurons. Cells' activity, having these channels, can then be manipulated by light. Chemogenetics, on the other hand, uses chemically engineered receptors and exogenous molecules specific for those receptors, to affect the activity of those cells. The engineered macromolecules used to design these receptors include nucleic acid hybrids,kinases, variety of metabolic enzymes, and G-protein coupled receptors (GPCRs) such as DREADDs.

DREADDs are the most common GPCRs used in chemogenetics. These receptors solely get activated by the drug of interest (inert molecule) and influence physiological and neural processes that take place within and outside of the central nervous system.

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