Figure 2
Time course of changes in effect of magnesium ion on pain and sensations. Fifteen volunteers were intradermally injected with 0.5 M MgSO4 (black square), 0.05 M MgSO4 (white square), 0.05 M MgCl2 (black triangle), or saline (white circle). Each volunteer was injected with three kinds of magnesium solution at intervals of at least one week. Local spontaneous pain (A) was reported by visual analogue scale (VAS), Tactile sensation (B) and pinch pain intensity (D) were reported by a numerical rating score (NRS). When MgSO4 and MgCl2 solutions were injected, transient irritating pain and local hypesthesia to mechanical stimuli appeared at the injection site. *p < 0.05 vs. control; **p < 0.01 vs. control, ***p < 0.001 vs. control. As values were similar among these three saline injections, we have put the representative data herein.