In order to investigate the effects of inflammatory mediators on the electrophysiological characteristics of the dorsal horn cells in the inflammatory-induced animal, activities of these cells to mechanical stimuli were recorded before and after intravenous administration of cyproheptadine, indomethacin and clonidine to the cat with carrageenin-induced inflammation.
The results obtained can be summarized as follows:
1) Following inductions of a cutaneous inflammation the activities of wide dynamic range (WDR) cell, high threshold (HT) cell and low threshold (LT) cell as well were greatly enhanced.
2) In the inflammation-induced animals an enhanced activities of LT cell to brush was not affected by indomethacin or clonidine, but the response to squeeze which was usually not appeared in normal animals was suppressed markedly by intravenously administered indomethacin.
3) Each one of the intravenously administered cyproheptadine(2㎎/㎏), indomethacin(5㎎/㎏)and clonidine(50㎕/㎏)significantly suppressed the activated responses of HT cells to pressure or squeeze in the cat with carrageenin-induced inflammation.
4) the enhanced activity of WDR cell due to the cutaneous inflammation was also remarkably inhibited after separate intravenous administration of cyproheptadine, indomethacin and clonidine and the response to squeeze was affected more strongly than that to brush.
5) The expanded receptive field of HT cells resulting from inflammation was abolisthed after intravenous administration of cyproheptadine, indomethacin and clonidine.
The results of present study suggest that in the animal with carrageenin-induced inflammantion, the WDR and HT cells could be activated by the direct and/or the sensitizing actions of inflammatory mediators.
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