电刺激听神经诱发小鼠脑干神经元活动的光信号及GABA能的作用  

Optical signal of the neuronal activity in mice brainstem evoked by electrical stimulation to the auditory nerve and GABAergic effect on it

作　　者：蔡竖平[1] 沈静[2] 土井直 

机构地区：[1]解放军总医院老年医学研究所,北京100853 [2]日本关西医科大学耳鼻喉科

出　　处：《中国神经科学杂志》2004年第2期105-109,共5页

摘　　要：目的　 使用光学记录的方法观察小鼠脑干听神经电刺激诱发冲动的时间 空间分布 ,及抑制性神经递质GABA和GABAA受体拮抗剂荷包牡丹碱 (BMI)对听觉诱发冲动的影响。 方法　 使用出生后早期的 (0～ 5d)ddy/ddy小鼠 ,在冷冻条件下制作有活性的脑干切片 ;用电压敏感染料 (NK 30 4 1)做脑片染色 ;16× 16像素的硅光电二极管阵列 (16× 16pixelsSiliconPhotodiodeArray)设备用来记录刺激听神经所诱发的光学信号 ;观察GABA及竞争性GABAA受体拮抗剂BMI对听神经诱发信号的作用。 结果　 刺激听神经诱发的光学信号以时间 空间分布的形式被记录。每一个光学信号分为两个成分 :快的峰电位样反应及慢的长时程反应。快电位的起始相具有突触前性质 ,晚期相具有突触后性质 ,慢的长时程反应可能与多突触传递有关。灌流液中使用 5 0 μmol/LGABA可最大限度地降低听神经诱发的脑干神经元信号的幅度 ,BMI可部分逆转GABA对此信号的作用。 结论　 多部位的光学系统可以记录电刺激听神经的诱发反应 ,光学信号显示了时间 空间分布的类型。应用药理学的方法可以分析诱发反应的性质。GABA对出生后早期小鼠的诱发反应有明显的抑制作用 ,其抑制作用部分是通过GABAA受体实现的。Objective To record the spatial-temporal pattern of auditory evoked impulses with multiple site optical technique in the brainstem slice of mice,and observe the effects of GABA , an important inhibitory neurotransmitter and of BMI, an antagonist against GABAA receptor on the auditory evoked impulses. Methods Early postnatal (day 0 to 5) mice were used to make alive brainstem slices in ice-cold artificial cerebral spinal fluid (ACSF). The slices were stained with a voltage-sensitive dye, NK3401. Optical signals evoked by electrical stimulation applied to the cut end of vestibulocochlear nerve (nVIIIth) were recorded with a 16×16 pixels silicon photodiode array apparatus. the effects of GABA as well as BMI on the auditory evoked signals were observed. Results Optical responses evoked by the stimulation to auditory nerves were recorded in spatial-temporal patterns. The optical signal that comes from one pixel was composed of two components, a spike-like fast response and a following long-lasting slow response;the initial phase of the fast response bears pre-synaptic characters, the late phase of which may be related to the post-synaptic activities. The slow signal may be responsible for the multiple synaptic transmissions. 50 μmol/L GABA applied in the bath solution largely inhibited the amplitude of auditory evoked signals;200 μmol/L BMI was able to partly reverse the effects of GABA on the auditory evoked signals in the present experiment. Conclusion The evoked optical signals were observed in the spatial-temporal pattern by multiple-site optical recording system. These signals could be analyzed by means of pharmacological tools. GABA showed the inhibitory effects on the auditory evoked signals in the brainstem slices, the inhibitory effects were displayed partly via GABAA receptor and this effect can be reversed by BMI.

关 键 词：电刺激听神经 诱发 小鼠 脑干神经元活动 光信号 GABA能 电压敏感染料 

分 类 号：Q424[生物学—神经生物学]