Skip to main content
. Author manuscript; available in PMC: 2016 Jul 1.
Published in final edited form as: Neuropharmacology. 2015 Jan 9;94:58–63. doi: 10.1016/j.neuropharm.2014.12.013

Figure 1.

Figure 1

This figure shows data from human subjects where pH 5.2 acidic buffer was infused into the tibialis anterior muscle and compared to saline controls. The infusion was started at time 9 and continued for 15 minutes. Pain ratings at the site of infusion and in the referred pain site (A), drawings of area pain felt by subject (B) and pressure pain thresholds at the site of infusion and in the referred pain site (C) were measured. A. Pain intensity ratings in the group infused with acidic buffer averaged around 2.5–3.0/10 during the infusion for the primary site of pain, and about 1/10 in the referred pain site at the ankle. B. The primary pain site occurred at the infusion site. A portion of the subjects, approximately 60%, had pain referred to the ankle, while 40% had only localized pain. C. Pain thresholds were significantly decreased from baseline during infusion of acidic buffer at both the site of infusion, primary hyperalgesia, and in the referred pain site, secondary hyperalgesia. Figures and data were redrawn from [18].