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Development of visual input to superior colliculus in fetal rats : in vivo optical imaging.

胎鼠上丘视觉输入的发育：体内光学成像。

基本信息

批准号：
09480242
负责人：
NAKAMURA Shoji
金额：
$ 8.64万
依托单位：
Yamaguchi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09480242/
关键词：
development visual system superior colliculus optical imaging synaptic potential glutamate GABA 胎仔電位感受性色素光学的記録法 in vivo 活動電位 TTX

项目摘要

The purpose of the present experiments is to study the functional development of neurons in the superior colliculus (SC)in fetal rats. For this purpose, the opticaI imaging system using a voltage-sensitive dye was employed in elucidating spatio- temporaI patterns of in vivo neural activity of the SC in fetal rats which were still connected with the dam by the intact umbilical cord. In the present experiments, signal propagation in the fetal SC caused by focal stimulation of the rostral SC was examined using the optical imaging system. Two to three fetal rats (embryonic day 21- 22 day) in each pregnant rat (Sprague-Dawley, 3 months) were used for each experiment. The fetal head was fixed to a conventional stereotaxic apparatus by the previously developed method (Nakamura and Sakaguchi, 1990 ; Sakata et al., 1998). For electrical stimulation of the SC, a bipolar stimulating electrode was implanted in the rostral part of the SC.Stimulation was given with single (1 msec duration) or ten train pulses (100 msec duration). Solution of a voltage-sensitive dye RH795 was applied to the surface of the SC for 1 hour. SC stimulation produced propagation of excitation rostro- caudally from the stimulating site. Inhibitory signal propagated diffusely in the SC.These signal propagation totally disappeared after application of TTX (3 mu M) to the surface of the SC.CNQX(non-NMDA receptor antagonist) blocked an early phase of excitatory propagation induced by focal SC stimulation, while the NMDA receptor antagonist AP-5 attenuated a late phase of excitation without affecting the early phase of excitation. The inhibitory propagation was remarkably attenuated by application of bicuculline.These results suggest that at late stages of the prenatal period in the rat SC, excitatory synaptic transmission occurs through both non-NMDA and NMDA receptors, while inhibitory synaptic transmission is mediated by GABA receptors.

本实验的目的是研究胎鼠上丘（SC）神经元的功能发育。为此，采用使用电压敏感染料的光学成像系统来阐明仍通过完整脐带与母鼠相连的胎鼠SC体内神经活动的时空模式。在本实验中，使用光学成像系统检查了由头侧 SC 的局灶刺激引起的胎儿 SC 中的信号传播。每个实验使用每只怀孕大鼠（Sprague-Dawley，3个月）中的2至3只胎鼠（胚胎第21-22天）。通过先前开发的方法将胎儿头部固定至常规立体定位装置(Nakamura和Sakaguchi，1990；Sakata等，1998)。为了对 SC 进行电刺激，将双极刺激电极植入 SC 的喙部。用单个脉冲（持续时间 1 毫秒）或十个脉冲序列（持续时间 100 毫秒）进行刺激。将电压敏感染料 RH795 的溶液施加到 SC 表面 1 小时。 SC 刺激产生从刺激部位向尾尾方向传播的兴奋。抑制信号在SC中广泛传播。将TTX（3μM）施加到SC表面后，这些信号传播完全消失。CNQX（非NMDA受体拮抗剂）阻断局灶性SC刺激诱导的兴奋性传播的早期阶段，而NMDA受体拮抗剂AP-5减弱了兴奋的晚期阶段而不影响兴奋的早期阶段。应用荷包牡丹碱可显着减弱抑制性传播。这些结果表明，在大鼠 SC 的产前后期，兴奋性突触传递通过非 NMDA 和 NMDA 受体发生，而抑制性突触传递由 GABA 受体介导。