Effect of the cation-chloride cotransporter inhibitor furosemide in a rat model of postoperative pain.

OBJECTIVE

Recently, evidence has accumulated to show that cation-chloride cotransporters (CCCs) participate in the modulation of pain transmission at the spinal cord level. To investigate whether CCC inhibitors might affect surgical pain, we examined the effect of furosemide in a rat incisional pain model.

DESIGN

We examined pain thresholds using von Frey filaments in intact and incision model Sprague-Dawley rats before and after intrathecal furosemide administration (100 µg/20 µL). Twenty-four rats were divided into four groups (N=6), groups A and B were intact rats, which received furosemide and its solvent, respectively. Groups C and D were incision rats, which received furosemide and its solvent, respectively. Non-parametric tests were used to calculate pain thresholds, and P<0.05 was considered significant.

RESULTS

Furosemide decreased the pain threshold (vs solvent) in intact rats for 2 hours after administration and caused excitatory behavior. However, furosemide increased the pain threshold in incision model rats ([1] at the incision point: at 20 minutes, 2 hours, 3 hours, 4 hours, and on the second to fifth days after incision; [2] at the remote point: at 20 minutes, 3-5 hours, and from the 3rd to the 7th day after incision) and improved wound recovery.

CONCLUSIONS

Intrathecal administration of the CCC inhibitor furosemide had antinociceptive effects in rats with incisional pain. Furosemide may be a novel treatment for postoperative pain.