Délèze J, Hervé J C
J Membr Biol. 1986;93(1):11-21. doi: 10.1007/BF01871014.
The gap junction morphology was quantified in freeze-fracture replicas prepared from rat auricles that had been either quickly frozen at 6 K or chemically fixed by glutaraldehyde, in a state of normal cell-to-cell conduction or in a state of electrical uncoupling. The general appearance of the gap junctions was similar after both preparative procedures. A quantitative analysis of three gap junctional dimensions provided the following measurements in the quickly frozen conducting auricles (mean +/- SD): P-face particles' diameter 8.27 +/- 0.74 nm (n = 5709), P-face particles' center-to-center distance 10.78 +/- 2.12 nm (n = 4800), and E-face pits' distance 9.99 +/- 2.19 nm (n = 1600). Corresponding values obtained from chemically fixed tissues were decreased by about 3% for the particle's diameter and about 5% for the particles' and pits' distances. Electrical uncoupling by the action of either 1 mM 2-4-dinitrophenol (DNP), or 3.5 mM n-Heptan-1-ol (heptanol), induced a decrease of the particle's diameter, which amounted to -0.69 +/- 0.01 nm (mean +/- SE) in the quickly frozen preparations and -0.71 +/- 0.01 nm in the chemically fixed ones. The particles' distance was decreased by -0.96 +/- 0.04 nm in the quickly frozen samples and by -0.90 +/- 0.03 nm in the chemically fixed ones and the E-face pits' distance was similarly reduced. All differences were statistically significant (P less than 0.001 for all dimensions). Electrical recoupling after the heptanol effect promoted a return of these gap junctional dimensions towards normal values, which was about 50% complete within 20 min. It is concluded that very similar morphological alterations of the gap junctional structure are induced in the mammalian heart by different treatments promoting electrical uncoupling and that these conformational changes appear independently of the preparative procedure. The suggestion that the observed decrease of the particles' diameter is genuinely related to the closing mechanism of the unit cell-to-cell channel set in their centers is thus confirmed.
在从大鼠耳廓制备的冷冻断裂复制品中对缝隙连接形态进行了定量分析，这些大鼠耳廓要么在6K下快速冷冻，要么用戊二醛化学固定，处于正常细胞间传导状态或电去偶联状态。两种制备方法后缝隙连接的总体外观相似。对三个缝隙连接尺寸的定量分析在快速冷冻的传导性耳廓中得到以下测量值（平均值±标准差）：P面颗粒直径8.27±0.74nm（n = 5709），P面颗粒中心到中心距离10.78±2.12nm（n = 4800），以及E面孔穴距离9.99±2.19nm（n = 1600）。从化学固定组织获得的相应值，颗粒直径减少约3%，颗粒和穴的距离减少约5%。通过1mM 2,4-二硝基苯酚（DNP）或3.5mM正庚醇（庚醇）的作用进行电去偶联，导致颗粒直径减小，在快速冷冻制剂中为-0.69±0.01nm（平均值±标准误），在化学固定制剂中为-0.71±0.01nm。颗粒间距离在快速冷冻样品中减少了-0.96±0.04nm，在化学固定样品中减少了-0.90±0.03nm，E面孔穴距离也同样减少。所有差异均具有统计学意义（所有尺寸P均小于0.001）。庚醇作用后的电再偶联促使这些缝隙连接尺寸恢复到正常值，在20分钟内约完成50%。结论是，促进电去偶联的不同处理在哺乳动物心脏中诱导了非常相似的缝隙连接结构形态改变，并且这些构象变化与制备过程无关。因此，所观察到的颗粒直径减小确实与位于它们中心的单位细胞间通道的关闭机制有关这一建议得到了证实。
