%0 Journal Article
%T Tumor Necrosis Factor-¦Á Suppresses Sustained Potassium Currents in Rat Small Diameter Sensory Neurons
%A Bao-Gang Liu
%A Maxim Dobretsov
%A Joseph R. Stimers and Jun-Ming Zhang
%J The Open Pain Journal
%D 2008
%I Bentham Open
%R 10.2174/1876386300902010001]
%X Tumor necrosis factor-¦Á (TNF-¦Á), a pro-inflammatory cytokine, produces pain and hyperalgesia by activating and/or sensitizing nociceptive sensory neurons. In the present study, using whole-cell patch clamp techniques, the regulation of potassium currents by TNF-¦Á was examined in acutely dissociated small dorsal root ganglion neurons. We found that acute application of TNF-¦Á inhibited, in a dose-dependent manner, the non-inactivating sustained potassium current without changing the rapidly inactivating transient current or the voltage-dependence of steady-state inactivation. The effects of TNF-¦Á on potassium currents were similar to that of prostaglandin E2 as reported previously and also demonstrated in the current study. Furthermore, indomethacin, a potent inhibitor for both cyclo-oxygenase (COX)-1 and COX-2, completely blocked the effect of TNF-¦Á on potassium currents. These results suggest that TNF-¦Á may sensitize or activate sensory neurons by suppressing the sustained potassium current in nociceptive DRG neurons, possibly via stimulating the intracellular production i.e. the synthesis and/or release of endogenous prostaglandins.
%U http://www.benthamscience.com/open/topainj/articles/V001/1TOPAINJ.htm