三叉神经尾侧脊束核内突触的亚显微结构

THE ULTRASTRUCTURE OF THE SYNAPSE IN THE SPINAL CAUDAL TRIGEMINAL NUCLEUS

在电镜下观察家兔和小白鼠三叉神经尾侧脊束核,于突触前膜上可见突触活性点;在突触前,后膜上有致密物质堆积,尤以突触后膜显著,偶尔在后膜下方的胞浆面见有突触下致密小体。在突触裂之间可见突触间丝。突触小泡有圆形和椭圆形、透明与颗粒小泡之分。尾侧脊束核内有大量轴突终末与树突。树突又分Ⅰ型(无突触小泡)和Ⅱ型(有少量突触小泡)。该核内的突触类型多数为轴-树突触,其次为轴-体突触和轴-轴突触,还见有树-树突触;按照突触小泡形状区分该核突触,则有S型、F型、S-F型与F-S型。突触丝球出现率为20%。本文讨论了突触类型、突触丝球与突触小泡的机能意义。

The synaptic pattern and its ultrastructure of the spinal caudal trigeminal nucleusin rabbits and mice were investigated with electromicroscope.The synapse in the spinal caudal trigeminal nucleus consists of the pre-and post-synaptic membranes and synaptic cleft.The active points of the synapse on thepresynaptic membranes were found.The dense substance is accumulated on the pre-and postsynaptic membranes,especially on the postsynaptic membranes.Occasionally,the subsynaptic dense bodies were encountered within the postsynaptic element.Theintersynaptic filaments were found within the synaptic clefts.The synaptic vesicleswere mainly found within the presynaptic terminals.Spherical,flat granular and ag-ranular vesicles were observed in the presynaptic terminals.A great numbers of the axon terminals,dendrites,axodendritic,axosomatic,axo-axonic and dendrodendritic synapses were identified in the spinal caudal trigeminalnucleus.The dendrites were classified into typeⅠ(without synaptic vesicle)and typeⅡ(containing less synaptic vesicle).According to the shape of the synaptic vesicle,the synapses of this nucleus are divided into S(sphere),F(flat),S-F and F-Stypes.The synaptic glomeruli are present about 20 per cent.The functional signi-ficance of the synaptic pattern,glomeruli and vesicles in this nucleus had beendiscussed.