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Abstract:   (45 Views)
Introduction: It seems that Valeriana officinalis (valerian) extract through gamma-amino-butyric acid A (GABAA) receptor possesses analgesic effect. The aim of the present study was to investigate the effect of muscimol and picrotoxin on pain sensitivity in male rats pretreated with valerian extract using the formalin test.
Methods: Thirty-five male rats weighing 200-250g in standard temperature 20±2 °C and light cycle of 12/ 12h used. Animals were randomly divided to 7 groups: Sham1 (injection of saline); Sham2 (pretreated with valerian + ICV injection of ACSF); experimental1 (injection of valerian extract); experimental2 and 3 (pretreated with valerian extract + ICV injection of muscimol 250 and 500 ng/rat); experimental4, 5 (pretreated with valerian extract + ICV injection of picrotoxin 250 and 500 ng/rat). Valerian extract 400 mg/kg was administrated by IP injection. Pain evaluation was done by the formalin test. Lateral ventricles cannulated unilaterally by the stereotaxic procedure.
Results: Data showed that valerian extract significantly decreased pain sensitivity in the late phase of the formalin test in comparison to sham1 group. Muscimol in both doses significantly decreased pain in comparison to sham1, while at the dose of 500 ng/rat significantly increased pain sensitivity in comparison to sham2 at late phases of formalin test. Picrotoxin at both doses significantly decreased pain sensitivity in comparison to sham1, while significantly increased pain sensitivity in comparison to the sham2 at late phases of formalin test. Conclusion: According to present results, valerian extract had analgesic effect through the GABAA receptor.
 
     
Types of Manuscript: Original Research | Subject: Pain and addiction