Palestini P, Masserini M, Fiorilli A, Calappi E, Tettamanti G
Department of Medical Chemistry and Biochemistry, University of Milan, Italy.
J Neurochem. 1993 Sep;61(3):955-60. doi: 10.1111/j.1471-4159.1993.tb03608.x.
Age-related changes of the ceramide composition of gangliosides were studied in the synaptosomal and myelin fractions from rat brain, carrying plasma membranes of neuronal and glial origin, respectively. The five major gangliosides (GM1, GD1a, GD1b, GT1b, and GQ1b) present in these fractions were separated and quantitated by normal-phase HPLC. Each ganglioside was then fractionated by reverse-phase HPLC into the molecular species carrying a single long-chain base (LCB). The largely preponderant LCBs in the synaptosomal and myelin fractions were the C18:1 and C20:1. The content of C20:1 LCB, generally low at 1 month, increased with age in all analyzed gangliosides and in all subcellular fractions and was greater in the "b series" than in the "a series" gangliosides. Remarkably, GM1 was the only ganglioside where the proportion of LCB 20:1 was higher in the synaptosomal fraction than in the myelin fraction. The fatty acid composition of the C18:1 or C20:1 LCB species of the different gangliosides in the synaptosomal and myelin fractions did not undergo appreciable changes with age. Stearic acid was largely predominant in all the gangliosides of the synaptosomal fraction, more in the C18:1 than in the C20:1 LCB species (80-90% vs. 60-70%). The gangliosides of the myelin fraction were characterized by a lower content of 18:0 and a much higher content of 16:0 and 18:1 fatty acids than those of the synaptosomal fraction. Thus, the ceramide composition is different in the gangliosides of neuronal and myelin origin and appears to be subjected to an age-related control.
研究了大鼠脑突触体和髓磷脂组分中神经节苷脂神经酰胺组成的年龄相关变化，这两个组分分别携带神经元和神经胶质来源的质膜。通过正相高效液相色谱法分离并定量这些组分中存在的五种主要神经节苷脂（GM1、GD1a、GD1b、GT1b和GQ1b）。然后通过反相高效液相色谱法将每种神经节苷脂分离成携带单个长链碱基（LCB）的分子种类。突触体和髓磷脂组分中占主导地位的LCB主要是C18:1和C20:1。C20:1 LCB的含量在1个月时通常较低，在所有分析的神经节苷脂和所有亚细胞组分中均随年龄增加，并且在“b系列”神经节苷脂中比在“a系列”神经节苷脂中更高。值得注意的是，GM1是唯一一种神经节苷脂，其突触体组分中LCB 20:1的比例高于髓磷脂组分。突触体和髓磷脂组分中不同神经节苷脂的C18:1或C20:1 LCB种类的脂肪酸组成并未随年龄发生明显变化。硬脂酸在突触体组分的所有神经节苷脂中占主导地位，在C18:1 LCB种类中比在C20:1 LCB种类中更多（80 - 90%对60 - 70%）。髓磷脂组分的神经节苷脂的特征是18:0含量较低，16:0和18:1脂肪酸含量比突触体组分的高得多。因此，神经节苷脂中神经酰胺的组成在神经元和髓磷脂来源的神经节苷脂中有所不同，并且似乎受到年龄相关的调控。
