Microinjection of octopamine at the ACC in Ap oa1 mice enhances inflammatory pain. (A) Behavioral nociceptive responses to hindpaw formalin injection, plotted in 5 minute intervals. Wild-type mice are plotted as filled circles (n = 7) while Ap oa1 mice are plotted as open circles (n = 6). Arrow shows the time for octopamine microinjection. MI: microinjection. (B) Data were grouped into 3 phases: early (acute), intermediate (inflammatory), and late phases. (C) Bilateral microinjection of 1 mM octopamine into the ACC of Ap oa1 mice (n = 5) did not alter hotplate (left) or tail-flick (right) responses compared to wild-type control (n = 3). (D) Location of lesion sites from all animals included in the study (left). Open circles represent injection sites of wild-type mice while filled circles represent injection sites of Ap oa1 mice. The right panel showed the example of lesion site location in the ACC of an H&E stained brain section. The injection sites are indicated by *, and the scale bar is 300 μm.
Wu et al. Molecular Pain 2008 4:40 doi:10.1186/1744-8069-4-40