声诱发短潜伏期负电位豚鼠模型的神经核团定位

The nucleus origin of acoustically evoked short latency negative response in guinea pigs

目的 通过建立声诱发短潜伏期负电位（acoustically evoked short latency negative response,ASNR）豚鼠模型,直流电损毁前庭神经核或蜗神经核,验证ASNR的神经来源.方法 24只健康豚鼠采用随机数字表法分为两组,正常对照组8只（16耳）,致聋组16只（32耳）.致聋组应用卡那霉素和利尿酸联合致聋,根据ASNR引出与否又分为ASNR组和非ASNR组.对照组、ASNR组及非ASNR组按损毁核团不同又分为前庭神经核损毁组及蜗神经核损毁组.所有动物均分别进行前庭神经核及蜗神经核定位,直流电损毁神经核团,24 h后观察声诱发脑干电位的改变.处死动物后脑干标本经冰冻切片及染色,显微镜下验证损毁部位.结果 致聋组16只豚鼠（32耳）中10耳出现ASNR（31.3％）.正常对照组豚鼠前庭神经核损毁后听性脑干反应（ABR）波形无明显改变,蜗神经核损毁后ABR仅余Ⅰ波.ASNR组中前庭神经核损毁组（7耳）ASNR均消失,而蜗神经核损毁组（3耳）ASNR均未消失;非ASNR组前庭神经核或蜗神经核损毁后ABR波形均无明显改变.脑干切片证实直流电破坏部位准确.结论 ASNR的责任神经核是前庭神经核,与蜗神经核无关.

Objective This study established a model of acoustically evoked short latency negative response （ASNR） in guinea pigs.Stereotaxic coordinate guided electrolytic lesion was applied to animal brainstem nuclei,the vestibular nucleus and the cochlear nucleus,to define the neural origin of ASNR.Methods Twenty four guinea pigs with normal hearing were randomly divided into the control group （8 subjects,16 ears） and the deafened group （16 subjects,32 ears）.Each animal experienced the auditory brainstem response （ABR） test.According to the presence of ASNR,the deafened group was further divided into ASNR group and non-ASNR group.Electrolytic lesion was conducted to the vestibular nucleus and cochlear nucleus respectively,followed by ABR test.The lesion structures were verified by brainstem slice and microscope.Results In deafened group,the ASNR was elicited in 10 ears （31.3%）.The ASNR was eliminated due to the electrolytic destruction to the vestibular nucleus,but it remained unchanged after the same procedure to the cochlear nucleus.Conclusion It is clear that the ASNR is originated from the vestibular nucleus,but not the cochlear nucleus.