RESUMO
PURPOSE: The effects of the 5-hydroxytryptamine (5-HT3) receptor antagonists on regional anaesthesia are complex and unclear. The present study was designed to test the hypothesis that granisetron, a selective 5-HT3 receptor antagonist, would decrease the duration of motor block, sensory block, and proprioception in a dose-dependent fashion in a rat model of bupivacaine-induced sciatic nerve blockade. MATERIALS AND METHODS: Thirty-eight male Wistar Albino rats that received unilateral sciatic nerve blocks were randomly divided into five experimental groups. Group B received a perineural of 0.3 ml of bupivacaine alone; Group BG800 received perineural 0.3 ml of bupivacaine and 800 µg of granisetron 10 min later; Group BG1200 received perineural 0.3 ml of bupivacaine and 1200 µg of granisetron 10 min later; Group BG1200IP received a perineural 0.3 ml of bupivacaine and an intraperitoneal injection of 1200 µg of granisetron 10 min later; and Group S was sham operated. A blinded investigator assessed motor, sensory and proprioception function every 10 min until the return of normal function. RESULTS: The medians for recovery times in Group B, Group BG800, Group BG1200, and Group BG1200IP were 105, 64, 85, and 120 min for motor function, respectively; 80, 64, 84, and 104 min for sensory function; 80, 63, 85, and 108 min were calculated for the proprioception function. The time to the return of normal motor, sensory, and proprioception function was not statistically significantly different between the groups (p > 0.05). Motor block did not develop in any of the rats in Group S. CONCLUSIONS: Local and systemic application of granisetron was not significantly decrease the duration of bupivacaine induced motor, sensory, and proprioception block of sciatic nerve in rat.