荷包牡丹碱和马钱子碱对小鼠皮层及下丘听神经元声反应潜伏期的影响

频率和强度是声音的两个重要参数，通常以听觉神经元动作电位发放频次编码这两个参数 . 研究表明，声反应潜伏期也可编码声音频率和强度，但尚不清楚潜伏期编码这两个参数究竟发生于哪一级听觉核团 . 如果声音参数由同级中枢编码，则这样的编码方式可能发生改变 . 反之，如果编码方式未发生变化，则意味着声音信息是由低位神经元编码的 . GABA 和甘氨酸 (Gly) 是听中枢普遍分布的抑制性递质 . 通过施加它们的拮抗剂荷包牡丹碱和马钱子碱，观测小鼠皮层和下丘听觉神经元声反应潜伏期的变化 . 结果表明，由反应潜伏期表征声音频率和强度的关系不因 GABA 和 Gly 作用的改变而发生变化，提示频率和强度与反应潜伏期之间的编码关系可能是由低位听神经元编码并向上传递的，而不是在同级中枢 ( 皮层或下丘 ) 完成的 .

The Effect of Bicuculline and Strychnine on The Latency of Neuron in Inferior Colliculus and Auditory Cortex of BALB/c Mouse

Frequency and intensity are two of the important parameters of sounds. Many researchers use spike rate of auditory neurons to represent the two parameters generally. Some studies showed that response latency may represent frequency and intensity too. However, it is not clear where the two parameters are encoded by response latency in the auditory pathway. GABA and glycine are two ubiquitous inhibitory neurotransmitters. Iontophoretically bicuculline (antagonist to GABA-A) or strychnine (antagonist to glycine) was injected to observe the change of response latency. If the relationship between response latency and intensity or frequency has changed, sound may be encoded locally. If the relationship keeps unchanged, this information may be transferred from the inferior nervous centres. The auditory neurons in the inferior colliculus and A1 area of auditory cortex of BALB/c mouse were studied. The results show that the relationship between response latency and intensity or frequency didn't change after the application of bicuculline or strychnine. It suggests that the encoding relationship between response latency and intensity or frequency didn't be completed in the inferior colliculus or A1 area of auditory cortex, but it is probably transferred from the inferior nervous centres.