异丙酚对大鼠下丘神经元第一动作电位延时-声强函数曲线的作用

Effect of propofol on the first spike latency-amplitude curve of rat inferior colliculus neurons

目的探讨异丙酚对大鼠下丘神经元第一动作电位延时-声强（FSL-A）函数曲线的作用,以揭示异丙酚麻醉过程导致听觉消失的神经电生理学机制。方法无特定病原体（SPF）级SD大鼠43只,雌雄不限,体质量200~250g。应用肌松药和小动物呼吸机建立听觉实验模型,将玻璃微记录电极刺入大鼠下丘中央核,用TDT3听觉研究系统采用细胞外记录的方式研究清醒和异丙酚麻醉（100mg/kg腹腔注射）后每间隔10min FSL-A的改变规律。结果共记录到43个单单位神经元,特征频率范围2.5~44kHz,1个单单位神经元呈现Offset反应,其余42只大鼠下丘神经元呈现Onset反应。给药后不同时点FSL-A函数曲线r2之间的比较差异具有统计学意义（P〈0.05）,给药后10min与给药前比较差异有统计学意义（P〈0.05）;给药前、后不同时间点FSL-A函数曲线r2〉0.95（P〈0.05）;同一大鼠给药后FSL-A曲线向下平移,可与给药前函数曲线完全重合。结论异丙酚改变大鼠下丘神经元FSL-A函数曲线位置从而影响听觉对声音强度的信息传递,但不改变对其编码的信息含义。

Objective To evaluate effect of propofol on the first spike latency-amplitude curve of rat inferior colliculus neurons and to find out mechanisms that propofol leds to the disappearance of auditory nerve electrophysiological.Methods 43healthy specefic pathogen free（SPF）grade sprague dawley（SD）rats（weighing 200-250g）were used to established wakeful animal models by ventilating with animal respirator after infusing vecuronium.A microelectrode was penetrated in the inferior colliculus（IC）,and then research first spike latency-amplitude（FSL-A）using a Tucker-Davis Technologies System 3（TDT3）before and after intraperitoneal injection of propofol 100mg/kg of each 10minutes interval.Results CFs ranging from 2.5to 44kHz.An acoustic response of neurons showed offset response,the remaining 42neurons showed onset response.r2 of FSL-A curve equations are significant difference between administered propofol before and after 10minutes（P〈0.05）,all of them are larger than 0.95（P〈0.05）.FSL-A curve after administration can shift the lower curve and coincident with the previous administration in the same rat.Conclusion Propofol affect auditory information transmission by convert localization of FSL-A curve of rat inferior colliculus neurons,but does not change the meaning of the information encoded.