Cerebral circulation during acute microgravity induced by free drop in anesthetized rats
Cerebral circulation during acute microgravity induced by free drop in anesthetized rats
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DOI：
10.2170/jjphysiol.53.223
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发表时间：
2003-06-01
期刊：
影响因子：
--
通讯作者：
Morita, H
中科院分区：
文献类型：
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作者：
Gotoh, TM;Fujiki, N;Morita, H
为了评价急性微重力（muG）对脑循环的影响，我们测量了麻醉大鼠（n=5）在4.5 s的muG自由落体过程中的颅内压（ICP）、膈肌水平的主动脉压和脑血流速度（CFV），然后计算眼水平的动脉压（AP（eye））和脑灌注压（CPP=AP（眼）-ICP）和估计的CPP-CFV关系。将大鼠置于平卧位和30 °头高位。在头高位，ICP、AP（眼）和CPP在muG期间分别显著增加2.2+/-0.4，12.3 +/-2.0和10.1+/-1.7 mmHg，而CFV没有显著变化。在平卧位，这些变量均未受到muG的显著影响。CPP-CFV关系的斜率仅在头高位时降低，表明muG增加了脑血管阻力。这些发现表明，重力（静水）压力的变化是理解急性muG期间脑循环变化的关键因素。[The Japanese Journal of Physiology 53：223-228，2003]。
To evaluate changes in the cerebral circulation during acute microgravity (muG), we measured intracranial pressure (ICP), aortic pressure at the diaphragm level, and cerebral flow velocity (CFV) in anesthetized rats (n=5) during 4.5 s of muG induced by free drop, then calculated arterial pressure at the eye level (AP(eye)) and cerebral perfusion pressure (CPP=AP(eye)-ICP), and estimated CPP-CFV relationship. The rats were placed in the flat and the 30degrees head-up positions. In the head-up position, ICP, AP(eye), and CPP were significantly increased by 2.2+/-0.4, 12.3+/-2.0, and 10.1+/-1.7 mmHg respectively during muG, whereas the CFV did not change significantly. In the flat position, none of these variables were significantly affected by muG. The slope of the CPP-CFV relationship was decreased only in the head-up position, suggesting that the cerebrovascular resistance was increased by muG. These findings indicate that the change in gravitational (hydrostatic) pressure is a key factor in understanding the changes in cerebral circulation during acute muG. [The Japanese Journal of Physiology 53: 223-228, 2003].