Low barometric pressure aggravates neuropathic pain in guinea pigs

Several clinical studies have demonstrated a consistent relationship between changes in meteorological factors, particularly barometric pressure, and pain intensity in subjects with chronic pain. We have previously demonstrated that exposure to artificially low barometric pressure (LP) intensifies pain-related behaviors in rats with neuropathic pain. In the present study, guinea pigs with unilateral L5 spinal nerve ligation (SNL) were placed in a pressure-controlled chamber and subjected to LP of 10 or 27 hPa below the ambient pressure. The SNL surgery led to increased hindpaw withdrawal frequencies to 34-, 59-, and 239-mN von Frey filaments (VFFs). When the SNL animals were subjected to both LP exposures consecutively, the hindpaw withdrawal frequencies further increased; the effect was most significant when the animals were exposed to LP 27 hPa below ambient pressure. In contrast, no change was seen in a group of sham-operated control animals. These results indicate that fluctuations in LP within the range of natural weather patterns can potentiate neuropathic pain in guinea pigs.

► Guinea pigs rendered neuropathic by spinal nerve ligation (SNL).
► The SNL led to increased hindpaw withdrawal frequencies to mechanical stimulation.
► The SNL animals were exposed to low barometric pressure (LP) by 10 hPa or 27 hPa.
► Under the both LP environments, the withdrawal frequencies further increased.
► These results indicated that LP exposure potentiated neuropathic pain in guinea pigs.