The investigators, whose results are published Oct. 15 in Cell, engineered a morphine-based compound called AM-3 that changes its shape in response to light in a certain frequency range. This conformational change alters AM-3’s degree of engagement with the mu-opioid receptor, the principal target of opioid painkiller drugs.
The researchers showed that with this light-switching or “photopharmacology” approach they could activate AM-3’s painkilling effect only where needed, allowing substantial pain relief without side effects in multiple preclinical pain models, including cancer pain models.