Research In Brief

Acetaminophen mechanism of action: Analgesic may work by inhibiting COX-3 activity in brain and spinal cord, N. V. Chandrasekharan, et al., Brigham Young University, report in online Proceedings of the National Academy of Sciences posted Sept. 19. BYU researchers say they found a third distinct COX enzyme, which they named COX-3, derived from same gene as COX-1. Researchers tested common analgesic/antipyretic drugs and NSAIDS for their ability to inhibit COX -1, -2 and -3 activity in presence of exogenously added arachidonic acid at two concentrations. "At the higher concentration of substrate, only COX-3 was inhibited by acetaminophen. Moreover, COX-3 was significantly more sensitive to acetaminophen than either COX-1 or- 2 at the lower substrate concentration," Chandrasekharan et al. report. Researchers say their findings suggest that "highly selective inhibitors can be made for COX-3"...