家兔下橄榄背侧副核的超微结构特点——电镜研究

本实验对7只家兔的下橄揽背侧副核进行了电镜观察。除发现已报道过的轴树突触、轴体突触及以树突为中心的突触球外,还见此核内有轴轴突触、轴突与胞体棘形成的突触,以轴突为中心的突触球及核内微纤维束。轴树突触最常见,突触后成分为树突或棘。轴体突触较少见。有一轴突终末与一胞体棘形成突触,同时还与一树突形成突触。轴轴突触前、后成分中均含圆形囊泡,有时形成轴-轴-树突触串。家兔下橄榄背侧副核内见有两种突触球,一种以树突为中心,另一种以轴突为中心。还发现两个轴突终末同时与另一轴突终末形成轴→轴→轴突触。下橄榄背侧副核内的复杂突触形式,说明传入冲动在其中可能经过扩散、会聚、突触前抑制及整合等复杂的过程。

THE ULTRASTRUCTURAL CHARACTERISTICS OF THE DORSAL ACCESSORY OLIVARY NUCLEUS IN THE RABBIT

The dorsal accessory olivary nucleus was studied with electron microscope in seven rabbits.The axo-axonal synapses,an axon being in contact synaptically with a spine of a perikaryon,the glomerulus with an axonal core and a bundle of microfibers within a nucleus of a neuron,as well as the already discovered axo- dendritic synapses,axo-somatic synapses and glomeruli with dendritic cores,were observed in this nucleus. The axo-dendritic synapses were often seen,the postsynaptic components of them were dendrites or spines.The axo-somatic synapses were fewer.An axonal terminal was seen synapsing to both a spine of a perikaryon and a dendrite.Both the presynaptic and postsynaptic components of the axo-axonal synapses contained spherical vesicles.Sometimes the axo-axo-dendritic synapses were observed.There were two kinds of glomeruli in this nucleus,one with dendritic core and the other axonal core.Two axons were discovered simultaneously synapsing with an axon. The complex synaptic pattern in the dorsal accessory olivary nucleus indicated that the afferent impulses would undergo diffusing,converging,presynaptic inhibition or integrating in this nucleus.