Nuclear receptor

A nuclear receptor is a protein inside the cell that binds a hormone or other small molecule and then acts directly on DNA to switch genes on or off.

Unlike cell-surface receptors such as GPCRs, which relay signals from outside the cell within seconds, nuclear receptors work more slowly by changing which proteins the cell manufactures, so their effects unfold over hours to days. The family includes receptors for steroid hormones, thyroid hormone, vitamin D and vitamin A derivatives, as well as the peroxisome proliferator-activated receptors that sense fatty acids and regulate metabolism and inflammation.

Nuclear receptors enter cannabinoid science mainly through PPAR-gamma, which several cannabinoids and endocannabinoids can activate in laboratory studies, offering a proposed pathway for effects on inflammation and neuroprotection that does not depend on CB1 or CB2. That work is preclinical. Because nuclear receptors control gene expression broadly, compounds that act on them are also of interest for drug-interaction and safety questions.