AXONAL TRANSPORT OF SULFATED GLYCOPROTEINS AND MUCOPOLYSACCHARIDES IN THE GARFISH OLFACTORY NERVE

—Application of ³⁵SO₄ to the olfactory mucosa of the long-nosed garfish is found to label sulfated macromolecules which are transported down the olfactory nerve. The transported molecules pass along the nerve as a discrete peak whose leading edge has a transport velocity of 206 ± 6 mm/day. A large portion of the radioactivity from the peak is deposited along the axon. At 2 days after isotope application 83% of the total nerve radioactivity is in the axons and the remaining 17% has accumulated at the terminals in the olfactory bulb. Characterization of sulfated material in the migrating peak indicates that both sulfated glycoproteins (isolated as glycopeptides) and mucopolysaccharides, including chondroitin sulfate and heparan sulfate, are undergoing transport.     

GLOBOID STRUCTURES IN THE CYTOPLASM OF RAPIDLY GROWING HELA CELLS

During the course of electron microscopic study of rapidly growing uninfected HeLa cells, it was found that numerous globoid bodies occurred in the cytoplasm. Reasons are given for suspecting that these structures are mitochondria.     

THE DISTRIBUTION OF CHOLINE ACETYLTRANSFERASE ACTIVITY IN VERTEBRATE RETINA1

Abstract— Choline acetyltransferase (ChAc) activity was determined in retinal layers from 10 vertebrates. In all animals, the highest activity was in the inner plexiform layer, intermediate activity in the inner nuclear and ganglion cell layers, and very low activity in the photoreceptor and outer plexiform layers and optic nerve. The pattern of distribution of enzyme activity within the inner nuclear layer corresponds quantitatively to the distribution of amacrine cells within that layer. A species difference of almost 90-fold was found between the lowest and highest values for ChAc activity in inner plexiform layer. The variation in enzyme activity found among homeotherms in inner nuclear and inner plexiform layers is related to the number of amacrine cell synapses in the inner plexiform layer. But the differences in enzyme activity are generally greater than those which have been found in numbers of amacrine cell synapses between species. The data suggest that cholinergic neurons in retina are to be found predominantly among the amacrine cell types and that not all amacrine cells will be found to be cholinergic.     

THE ULTRASTRUCTURE OF ADULT VERTEBRATE PERIPHERAL MYELINATED NERVE FIBERS IN RELATION TO MYELINOGENESIS

Adult chameleon myelinated peripheral nerve fibers have been studied with the electron microscope in thin sections. The outer lamella of the myelin sheath has been found to be connected as a double membrane to the surface of the Schwann cell. The inner lamella is connected as a similar double membrane with the double axon-Schwann membrane. The relations of these double connecting membranes suggest that the layered myelin structure is composed of a double membrane which is closely wound about the axon as a helix. These findings support the new theory of myelinogenesis proposed recently by Geren. The possible significance of these results with respect to cell surface membranes and cytoplasmic double membranes is discussed.     

EVIDENCE FOR THE OCCURRENCE AND DISTRIBUTION OF INORGANIC POLYPHOSPHATES IN VERTEBRATE TISSUES

Evidence for the occurrence of polyphosphates having apparent chain-lengths ranging from less than 10 to over 5000 orthophosphate units has been found in adult brain as well as in a number of other mammalian tissues which have been examined. There appears to be three times as much polyphosphate in rat brain as there is in rat liver. Adult rat brain appears to contain at least 15 μg of phosphorus as polyphosphate per g of fresh tissue. In addition, neural polyphosphate is extremely labile to catabolic degradation after death whereas hepatic polyphosphate is relatively more stable. The nature of this inorganic polymer was elucidated through use of the technique of ³¹P nuclear magnetic resonance spectroscopy. Further structural evidence was obtained by application of the isotopic dilution technique to ³²P-labelled neural polyphosphate mixed with an abiotically prepared inorganic polyphosphate. The conditions and rates of hydrolysis of the biological polyphosphate and a non-biological polyphosphate were comparable.     

HISTOCHEMICAL STUDIES ON MUCOPROTEINS IN NERVE CELLS OF THE DOG

Autonomic and sensory ganglion cells in the senile dog contain a deposition of PAS-positive substances which has been shown to be mucoprotein in nature. Data are presented to show that this PAS-positive mucoprotein can be demonstrated by metachromatic staining with toluidine blue after the mucoprotein is sulfated. This procedure indicates that mucoprotein is also present in a granular form in all nerve cells in both senile and young dogs. The evidence for this is further substantiated by the use of the aldehyde-fuchsin stain following both periodic acid oxidation and sulfation. The granular and non-granular deposition can be demonstrated by the periodic acid-aldehyde-fuchsin method due to the affinity of the aldehyde-fuchsin stain for aldehydes. It can be demonstrated following the sulfation-aldehyde-fuchsin method owing to the affinity of the stain for the sulfuric group. The evidence for this latter phenomenon has been reported by Scott and Clayton (6). It is concluded that mucoprotein is present in a granular form in all nerve cells in both senile and young dogs but is not concentrated enough in the latter to be demonstrated by the PAS method.     

损伤视神经后斑马鱼视网膜神经节细胞数量和分布的变化

中枢神经系统的再生是神经科学领域的一个重要课题。鱼类和两栖类的视神经作为中枢神经系统的一部分,具有再生的能力。已知在损伤视神经后,对与视神经纤维直接相连的视网膜神经节细胞的形态结构,数量和分布等产生一系列的影响。视神经再生过程中细胞学研究在很大程度上依赖于示踪方法和其它技术的发展,结合光镜和电镜,它们仅对神经细胞末梢的精细结构和神经细胞间突触连接构筑等研究较准确详实,但对视网膜神经节细     

大熊猫胃肠道内分泌细胞分布型的研究

本文用ＰＡＰ法对３只大熊猫胃底,幽门腺区、十二脂肠,空肠,回肠、结肠和直肠的五羟色胺,生长抑素,胃素,胆囊收缩囊,神经降压素、胃动素、抑胃多肽、胰高血糖素、血管活性肠肽和内啡肽的ＩＲ细胞进行了研究。结果表明,大熊猫胃肠道粘膜上皮中具有前八种ＩＲ细胞。对７年龄个体胃肠各段相对数量的比较和各段内分布情况的观察结果表明,除五羟色胺ＩＲ细胞在空肠分布较多外,大多数种类的ＩＲ细胞集中分布于幽门区和十二指肠,     

玉米螟幼虫侧单眼的神经鞘和胶质细胞

用透射电镜观察了欧洲玉米螟Ostrinia nubilalis(Hbner)5龄幼虫侧单眼神经的神经围膜、周神经细胞和其他神经胶质.神经围膜与若干周神经细胞包围若42根轴突.周神经细胞的原生质膜在它们的侧面和内面高度卷曲,并与相邻细胞交错对插,这是细胞与细胞间的特殊连接方式;它们的外面以桥粒和半桥粒固定在神经围膜内面.周神经细胞由神经胶质细胞演化而来,所形成的膜称神经束膜,它与神经围膜组成围在侧单眼神经外面的神经鞘.侧单眼神经内的神经胶质细胞大而平整,具有许多突起物(相当于脊椎动物的少突神经胶质细胞),每一个突起物包被一个感光轴突.神经胶质细胞包被轴突的形式有三种不同的类型:一种是相邻轴突间插入15层神经胶质细胞突起物所形成的普通轴系膜形式,另两种是神经胶质细胞突起物在一个轴突的周围,由一些褶所形成的不同形式.最后,对这些神经胶质细胞以不同形式包被轴突的功能意义进行了讨论.     

EXPERIMENTALLY INDUCED CHANGES IN THE BASE COMPOSITION OF THE RIBONUCLEIC ACIDS OF ISOLATED NERVE CELLS AND THEIR OLIGODENDROGLIAL CELLS

The effect of tricyano-amino-propene, a dimer of malononitrile, on the base composition of the RNA in isolated Deiters' nerve cells and their oligodendroglial cells has been studied using a microelectrophoretic method. Tri-a-p in a dose of 20 mg/kg has the effect of increasing the RNA and protein content per nerve cell by 25 per cent and decreasing the glia RNA by 45 per cent. The RNA base composition of the nerve cells from the control animals differs from that of their glial cells. The guanine of the nerve cell is significantly higher than that of the glia, but the content of cytosine is higher in the glia than in the RNA of nerve cell. The cytosine of nerve cells decreased significantly after tri-a-p administration. In the glial cells the cytosine showed a 20 per cent increase, and the guanine a 25 per cent decrease. Tri-a-p sharpened the difference in RNA composition already existing between the control nerve cells and their glial cells by almost 300 per cent for the guanine and by 400 per cent for the cytosine. The chemical and functional relationship between the nerve cell and its oligodendroglial cells is discussed.     

消化管括约肌部VIP免疫活性神经细胞分布

应用免疫组织化学方法研究了食管下部,幽门和回盲部肌间神经丛内ＶＩＰ免疫活性神经细胞的分布。ＶＩＰ免疫活性神经细胞在括约肌部比相邻部位数量多。并用Ｏｐｅｎ－ｔｉＰ法测量了刺激迷走神经后食管下段括约肌部压力的变化。用高阈值参数电刺激迷走神经引起预先投给阿托品的狗食管下段括约肌部压力的降低;这样条件下延长迷走神经刺激引起肌间神经丛内ＶＩＰ免疫活性神经细胞数量明显增加。由此结果提示含有或产生ＶＩＰ的神经细胞可能接受迷走神经的控制。由于刺激节前迷走神经纤维可能作用到这些细胞。