Effects of intrathecal Iidocaine on propofol-induced sedation and content of lidocaine in brain tissues in rats / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effects of intrathecal (IT) lidocaine on propofol-induced sedation and content of lidocaine in brain tissues in rats.Methods Twenty male Sprague-Dawley rats,aged 2-3 months,weighing 250-350 g,were equally and randomly assigned to one of four groupscontrol group (group C),iv lidocaine group (group IV-L),IT normal saline group (group IT-NS) and IT lidocaine group (group IT-L).Groups IT-NS and IT-L received IT normal saline 15μl and 2％ lidocaine 15 μl,respectively.Group IV-L received iv 2％ lidocaine 15 μl.Propofol was infused starting from 10 min after IT or iv administration.When the eyelash reflex disappeared,the infusion of propofol was stopped and the dose of propofol consumed was recorded.The rats were sacrificed in IT-L and IV-L groups and brains were removed for determination of lidocaine level in brain tissues (by RP-HPLC).Results Compared with groups C,IV-L and IT-NS,the dose of propofol consumed when the eyelash reflex disappeared was significantly decreased in group IT-L (P ＜ 0.05).No significant difference was found in the propofol requirement when the eyelash reflex disappeared between groups C,IV-L and IT-NS and in the content of lidocaine in brain tissues between groups IV-L and IT-L (P ＞ 0.05).Conclusion Sedation induced by lidocaine administered intrathecally is not due to a direct action of lidocaine on the brain in rats.