I. Beritashvili Center of Experimental Biomedicine, 14 Gotua Street, 0160 Tbilisi, Georgia.
Micron. 2012 Sep;43(9):948-53. doi: 10.1016/j.micron.2012.03.016. Epub 2012 Apr 6.
Porosomes are the universal secretory machinery in cells, where membrane-bound secretory vesicles transiently dock and fuse to release intravesicular contents to the outside of the cell during cell secretion. Studies using atomic force microscopy, electron microscopy, electron density and 3D contour mapping, provided rich nanoscale information on the structure and assembly of proteins within the neuronal porosome complex in normal brain. However it remains uncertain whether pathological conditions that alter process of neurotransmission, provoke alterations in the porosome structure also. To determine if porosomes are altered in disease states, the current study was undertaken for first time using high resolution electron microscope. One of pathologies that produce subtle alteration at the presynaptic terminals has been demonstrated to be hypokinetic stress. The central nucleus of amygdale is the brain region, where such alterations are mostly expressed. We have examined the width and depth of the neuronal porosome complex and their alterations provoked by chronic hypokinetic stress in above mentioned limbic region. Specifically, we have demonstrated that despite alterations in the presynaptic terminals and synaptic transmission provoked by this pathological condition in this region, the final step/structure in neurosecretion--the porosome--remains unaffected: the morphometric analysis of the depth and diameter of this cup-shaped structure at the presynaptic membrane point out to the heterogeneity of porosome dimensions, but with unchanged fluctuation in norm and pathology.
质膜纳米通道（porosomes）是细胞中通用的分泌机制，在细胞分泌过程中，膜结合的分泌小泡短暂停靠并融合，将小泡内的内容物释放到细胞外。使用原子力显微镜、电子显微镜、电子密度和 3D 轮廓映射的研究，为正常大脑中神经元质膜纳米通道复合物内的蛋白质结构和组装提供了丰富的纳米尺度信息。然而，目前仍不确定改变神经递质传递过程的病理条件是否也会引起质膜纳米通道结构的改变。为了确定质膜纳米通道是否在疾病状态下发生改变，本研究首次使用高分辨率电子显微镜进行了研究。一种在突触前末端产生细微改变的病理学已被证明是运动不足应激。杏仁核中央核是大脑中表达这种改变的区域。我们已经检查了上述边缘区域慢性运动不足应激引起的神经元质膜纳米通道复合物的宽度和深度及其改变。具体来说，我们已经证明，尽管该病理条件引起了该区域突触前末端和突触传递的改变，但神经分泌的最后一步/结构——质膜纳米通道——仍然未受影响：对突触前膜上这种杯状结构的深度和直径的形态计量分析表明，质膜纳米通道的尺寸存在异质性，但在正常和病理状态下波动不变。
