CONFORMATIONAL CHANGES IN MYOCARDIAL NUCLEI OF RATS
CONFORMATIONAL CHANGES IN MYOCARDIAL NUCLEI OF RATS
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DOI：
10.1161/01.res.24.2.189
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发表时间：
1969-01-01
影响因子：
20.1
通讯作者：
CANCILLA, PA
中科院分区：
文献类型：
--
作者：
BLOOM, S;CANCILLA, PA
已发现心肌细胞核在收缩-舒张周期期间核构象发生巨大变化。这通过大鼠心肌收缩和松弛纤维中纵向和横向取向的细胞核的电子显微照片得到证实。收缩纤维的平均肌节长度为l.7μ±0.1μ（±1SD），延伸纤维的平均肌节长度为2.1μ±0.3μ。通过比较核膜上两点之间 6.64μ 的直线距离与相同点之间沿膜的距离 (NML) 来量化膜起皱的量。起皱程度用“冗余”表示，即[(NML - 6.64)/6.64] x 100。纵向切片显示两组细胞核的平均长度和宽度存在显着差异，收缩纤维的轴比为2.2，伸长纤维的轴比为4.8。然而，两个群体之间最明显的差异是核膜冗余，延伸和收缩纤维分别为 2.1% 和 27.0%。尽管核膜冗余度的差异在纵向切片中很明显，但在横向切片中并不明显。结论是，在心脏收缩期间，心肌细胞核随着膜垂直于长轴的折叠而被纵向压缩。肌节长度的变化与核长度和膜冗余的变化的相关性表明核膜与某些肌节片段的耦合。
Myocardial nuclei have been found to undergo a dramatic change in nuclear conformation during the contraction-relaxation cycle. This was demonstrated with electron micrographs of longitudinally and transversely oriented nuclei in contracted and relaxed fibers of rat myocardium. The contracted fibers had a mean sarcomere length of l.7µ ± 0.1µ (±1 SD), and extended fibers had a mean sarcomere length of 2.1µ ± 0.3µ. The amount of membrane wrinkling was quantified by comparing a straight-line distance of 6.64µ between two points on the nuclear membrane to the distance along the membrane (NML) between the same points. The degree of wrinkling was expressed as "redundancy" which is [(NML - 6.64)/6.64] x 100. Longitudinal sections showed a marked difference in mean length and width in the two populations of nuclei, with an axial ratio of 2.2 in the contracted, and 4.8 in the extended fibers. The most obvious difference between the two populations, however, was the nuclear membrane redundancy, which was 2.1% and 27.0% for the extended and contracted fibers, respectively. Although a difference in nuclear membrane redundancy was clear in longitudinal sections, it was not apparent in transverse sections. It is concluded that during systole myocardial nuclei become longitudinally compressed with folding of the membrane perpendicular to the long axis. The correlation of the change in sarcomere length with the change in nuclear length and membrane redundancy suggests a coupling of the nuclear membrane to some sarcomere segment.