Pain perception in mice is maintained for several days by augmented activity of a particular enzyme in a brain area associated with chronic pain. Blocking the enzyme, PKMζ, with a peptide inhibitor alleviates the pain.

Bong-Kiun Kaang at Seoul National University, Min Zhuo at the University of Toronto in Canada and their colleagues show that in the days following a nerve injury, mice had higher levels of PKMζ in a brain region known as the anterior cingulate cortex (ACC). Injecting the PKMζ inhibitor into the ACC led to a drop in synaptic activity, or neuronal communication, in that region, as well as a decrease in pain responses.

The authors suggest that PKMζ mediates chronic pain by boosting synaptic transmission in the ACC.

Science 330, 1400–1404 (2010)