Toward the functional dissection of neuronal circuits, a number of new genetic tools have been developed that enable rapid and reversible manipulation of genetically defined neuronal subtypes in intact mammalian brain circuits. Alongside the breakthrough technology of optogenetics, receptor-ligand pairs provide complementary approaches to modulate neuronal activity using chemical genetics.
Wulff, P., & Arenkiel, B. R. (2012). Chemical genetics: receptor-ligand pairs for rapid manipulation of neuronal activity. Current Opinion in Neurobiology, 22(1), 54-60. https://doi.org/10.1016/j.conb.2011.10.008