1. TRPM2 deficiency impairs carrageenan-induced inflammatory pain.
TRPM2 deficiency impairs carrageenan-induced inflammatory pain. WT and TRPM2-KO mice were injected intraplantarly with carrageenan. A–C, The 50% withdrawal threshold to mechanical stimulation in the von Frey filament test (n = 8; A), latency to thermal stimuli in the Hargreaves test (n = 6; B), and paw edema (n = 8; C) were determined at the indicated times. *p < 0.05; **p < 0.01; ***p < (compared with WT mice). D, The H2O2 content in the paws of WT and TRPM2-KO mice was measured 4 h after the injection of saline (Sal) or carrageenan (Carr). n.s., Not significant. n = 3–4. E, Expression level of TRPM2 mRNA in the carrageenan-inflamed paws of WT mice was measured by real-time PCR at the indicated times. TRPM2 mRNA level was normalized to the GAPDH mRNA level and expressed relative to the control (fold). **p < 0.01 (compared with noninjected control paws); n = 3. F, G, Expression levels of TRPM2 mRNA were measured in F4/80-positive macrophages (F) and Gr-1-positive neutrophils (G) isolated from the carrageenan-inflamed paw by MACS. The TRPM2 mRNA level was normalized to the GAPDH mRNA level and expressed relative to the samples 4 h after the carrageenan injection, because macrophages and neutrophils could not be isolated from the noninjected control paws. N.D., Not determined. n = 4.
Kayo Haraguchi et al. J. Neurosci. 2012;32:
©2012 by Society for Neuroscience