Ahuja T K, Wu S H
Laboratory of Sensory Neuroscience, Institute of Neuroscience, Carleton University, K1S 5B6, Ottawa, Ont., Canada.
Hear Res. 2000 Nov;149(1-2):33-45. doi: 10.1016/s0378-5955(00)00159-3.
To better understand the development of the dorsal nucleus of the lateral lemniscus (DNLL), intrinsic membrane properties and synaptic responses of DNLL neurons in brain slice preparations were examined. Intracellular recordings were taken from DNLL neurons of rat pups at postnatal days 4-8 (early group), 10-12 (intermediate group) and 16-18 (late group). In response to positive current injection, neurons in the early group displayed firing with lower frequency and a longer action potential duration in comparison to the intermediate and late groups. The action potential amplitude of DNLL neurons increased during development. Postsynaptic potentials (PSPs), with excitatory predominance, were elicited by electrical stimulation of the lateral lemniscus and commissure of Probst throughout the three age groups. Neurons showed a longer latency and rise time of the PSPs in the early group in comparison with those in the intermediate and late groups. These results suggest that the early DNLL neurons display physiological characteristics associated with immature neurons, while the other two groups tend to illustrate mature-like neuronal properties. Furthermore, it seems that the neurons at day 10-12 are in a transitional period of development, which coincides with the onset of hearing.
为了更好地理解外侧丘系背核（DNLL）的发育情况，研究人员对脑片标本中DNLL神经元的内在膜特性和突触反应进行了检测。在出生后第4 - 8天（早期组）、10 - 12天（中期组）和16 - 18天（晚期组）的幼鼠DNLL神经元上进行了细胞内记录。与中期组和晚期组相比，早期组的神经元在受到正向电流注入时，放电频率较低，动作电位持续时间较长。DNLL神经元的动作电位幅度在发育过程中增加。在所有三个年龄组中，通过电刺激外侧丘系和普罗布斯特连合可诱发以兴奋性为主的突触后电位（PSP）。与中期组和晚期组相比，早期组的神经元PSP潜伏期和上升时间更长。这些结果表明，早期的DNLL神经元表现出与未成熟神经元相关的生理特征，而其他两组则倾向于表现出类似成熟神经元的特性。此外，似乎10 - 12天的神经元正处于发育的过渡期，这与听力开始的时间相吻合。
