The Role of NMDARs Ligands on Antinociceptive Effects of Pregabalin in the Tail Flick Test

BACKGROUND: Pregabalin as a new anticonvulsant has been used in different pain treatments. OBJECTIVES: The aim of this study was to investigate the role of N-methyl-D-aspartate (NMDA) ligands in antinociceptive effect of pregabalin in mice using tail flick. MATERIALS AND METHODS: NMDA (15 and 30 mg/kg) as an agonist or MK801 (0.02 and 0.05 mg/kg) as an antagonist were injected intraperitoneally either alone or 15 minutes before antinociceptive dose of pregabalin (100 mg/kg). Then the latency times and %MPE were measured in the tail flick assay during 75 minutes. RESULTS: NMDA and MK801 had no effects alone. NMDA pretreatment significantly decreased the latency times of pregabalin till 75(th) minutes. In NMDA pretreated groups, %MPE(30) unlike %MPE(75) decreased significantly compared to those of pregabalin. MK801 delayed the latency times in pretreated groups, but %MPE(30) and %MPE(75) did not change significantly compared to pregabalin alone. CONCLUSIONS: Our findings support the role of NMDARs in pregabalin antinociception, because the NMDAR agonist, unlike the antagonist, decreased the antinociceptive effect of pregabalin, even if tail flick is not an adequate pain assessment method in this regard.