Nakagawa Aya, Uno Atsuhiko, Horii Arata, Kitahara Tadashi, Kawamoto Masahiro, Uno Yoshihiro, Fukushima Munehisa, Nishiike Suetaka, Takeda Noriaki, Kubo Takeshi
Department of Otolaryngology, Osaka University Medical School, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
Brain Res. 2003 Oct 3;986(1-2):114-23. doi: 10.1016/s0006-8993(03)03220-7.
Altered gravity environments including both hypo- and hypergravity can elicit motion sickness. Vestibular information is known to be essential for motion sickness, but its other neural substrates are poorly understood. We previously showed that bilateral lesions of the amygdala suppressed hypergravity-induced motion sickness in rats, using pica behavior as an emetic index. We show in the present study that during hypergravity stimulation, vestibular information activated the central nucleus of the amygdala (CeA), as determined by the induction of Fos expression, in comparison between normal and bilaterally labyrinthectomized rats. The finding that Fos expression was confined to the CeA and almost completely absent in other subnuclei of the amygdala contrasted with many previous studies that used other stressful stimuli such as foot shock, restraint and forced swimming, suggesting a specific vestibular effects on the amygdala. Prolongation of hypergravity resulted in reduction of Fos expression in the CeA, suggesting a process of habituation. Such decreases appeared earlier than in the vestibular nucleus, suggesting that adaptive changes in the CeA to hypergravity were independent of changes in the vestibular input. Our results suggest the amygdala is a neural substrate involved in the development of and habituation to motion sickness.
包括低重力和高重力在内的重力环境改变都可能引发晕动病。已知前庭信息对于晕动病至关重要，但其其他神经基质却知之甚少。我们之前利用异食癖行为作为呕吐指标，表明杏仁核双侧损伤可抑制大鼠高重力诱导的晕动病。在本研究中我们发现，在高重力刺激期间，通过Fos表达的诱导来确定，与正常大鼠和双侧迷路切除大鼠相比，前庭信息激活了杏仁核中央核（CeA）。Fos表达局限于CeA且在杏仁核的其他亚核中几乎完全不存在这一发现，与许多之前使用诸如足部电击、束缚和强迫游泳等其他应激刺激的研究形成对比，表明前庭对杏仁核有特定影响。高重力的延长导致CeA中Fos表达减少，表明存在习惯化过程。这种减少比在前庭核中出现得更早，表明CeA对高重力的适应性变化独立于前庭输入的变化。我们的结果表明杏仁核是参与晕动病发生和习惯化的神经基质。
