Pompeiano O, d'Ascanio P, Centini C, Pompeiano M, Cirelli C, Tononi G
Dipartimento di Fisiologia e Biochimica, Scuola Medica, Università di Pisa, Pisa, Italy.
Acta Otolaryngol Suppl. 2001;545:120-6. doi: 10.1080/000164801750388289.
Changes in neuronal activity resulting in somatic and vegetative deficits occur during different space flight conditions. Immediate early genes (IEGs: c-fos and Fos-related antigen [FRA]) are useful indicators of changes in neuronal activity and plasticity. They are induced within minutes of several extracellular stimulations, while the corresponding proteins persist for hours (Fos) or days (FRAs). Changes in IEG expression are likely to contribute to adaptation to microgravity and readaptation to the terrestrial environment. During the NASA Neurolab Mission (STS-90), changes in IEG expression were studied in adult male albino rats (Fisher 344) sacrificed at flight day (FD) 2 (24 h after launch), FD14 and at similar time points after re-entry (R + 1, 24 h after re-entry, and R + 13). These time points were chosen to maximize the probability of detecting changes in IEG expression related to changes in gravitational fields occurring during the mission, e.g. (i) increase in gravitational force from 1 to 3 g during the launch, before reaching about 0 g at FD2; (ii) adaptation to 0 g at FD14; (iii) increase in gravity from 0 to approximately 1.5-1.8 g before reaching 1 g at R + 1; and (iv) readaptation to 1 g at R + 13. Fos- and FRA-positive cells were identified in the brainstem of flight rats and ground-based controls using immunocytochemistry. With respect to control rats, the number of labeled cells increased in flight animals in the medial and spinal vestibular nuclei (but not in the lateral vestibular nucleus) at FD2, decreased at FD14, greatly increased at R + 1 and returned to baseline levels at R + 13. Similar changes in IEG expression were also observed in the nucleus of the solitary tract, the area postrema and the central nucleus of the amygdala. In particular, in these vegetative areas the number of Fos-positive cells decreased in flight rats with respect to controls at FD14, i.e. after exposure to 0 g, but significantly increased at R + 1, i.e. after return to 1 g. Thus, altered gravitational fields produced molecular changes in vestibular nuclei controlling somatic functions, as well as in related medullary and basal forebrain structures regulating vegetative functions.
在不同的太空飞行条件下，会发生导致躯体和植物神经功能缺损的神经元活动变化。即刻早期基因（IEGs：c-fos和Fos相关抗原 [FRA]）是神经元活动和可塑性变化的有用指标。它们在几种细胞外刺激后的几分钟内被诱导产生，而相应的蛋白质会持续数小时（Fos）或数天（FRAs）。IEG表达的变化可能有助于适应微重力以及重新适应地球环境。在美国国家航空航天局神经实验室任务（STS-90）期间，研究了在飞行日（FD）2（发射后24小时）、FD14以及重返地球后相似时间点（R + 1，重返地球后24小时，以及R + 13）处死的成年雄性白化大鼠（Fisher 344）中IEG表达的变化。选择这些时间点是为了最大程度地提高检测到与任务期间引力场变化相关的IEG表达变化的可能性，例如：（i）发射期间引力从1 g增加到3 g，在FD2时达到约0 g之前；（ii）在FD14时适应0 g；（iii）在R + 1时引力从0 g增加到约1.5 - 1.8 g，在达到1 g之前；以及（iv）在R + 13时重新适应1 g。使用免疫细胞化学方法在飞行大鼠和地面对照组的脑干中鉴定Fos和FRA阳性细胞。与对照大鼠相比，飞行动物在内侧和脊髓前庭核（但外侧前庭核中没有）的FD2时标记细胞数量增加，在FD14时减少，在R + 1时大幅增加，并在R + 13时恢复到基线水平。在孤束核、最后区和杏仁核中央核中也观察到了IEG表达的类似变化。特别是，在这些植物神经区域，飞行大鼠在FD14（即暴露于0 g后）相对于对照组Fos阳性细胞数量减少，但在R + 1（即返回1 g后）显著增加。因此，引力场的改变在前庭核中产生了控制躯体功能的分子变化，以及在调节植物神经功能的相关延髓和基底前脑结构中也产生了分子变化。
