Researchers have identified a brain mechanism that could be a drug target to help prevent tolerance and addiction to opioid pain medication, such as morphine, according to a study by Georgia State University and Emory University.
The findings, published in the Nature journal, Neuropsychopharmacology, in August, show for the first time that morphine tolerance is due to an inflammatory response produced in the brain. This brain inflammation is caused by the release of cytokines, chemical messengers in the body that trigger an immune response, similar to a viral infection.
Researchers’ results show blocking a particular cytokine eliminated morphine tolerance, and they were able to reduce the dose of morphine required to alleviate pain by half.
‘These results have important clinical implications for the treatment of pain and also addiction,’ said Lori Eidson, lead author and a graduate student in the laboratory of Dr Anne Murphy in the Neuroscience Institute of Georgia State.
‘Until now, the precise underlying mechanism for opioid tolerance and its prevention have remained unknown.’
The study also found that tolerance to morphine develops rapidly. Administering one dose of morphine to rats for three days was sufficient to induce tolerance.
