ULTRASTRUCTURE OF TH, 5-HT, SP AND L-ENK IMMUNOREACTIVE FIBERS AND BOUTONS IN THE LATERAL HORN OF THE RAT SPINAL CORD / 解剖学报

ABSTRACT

The synaptic organization of monoaminergic and peptidergic fibers in the lateral horn of the rat spinal cord was studied under electron microscopy by immunocytochemistry ABC method. TH, 5-HT, SP and L-ENK immunoreactive fibers in the lateral horn were unmyelinated. In the cell clusters of the lateral horn these fibers appeared in the space between cell bodies and some pressed on the soma, but axosomatic synapses were seldom found. Many immunoreactive fibers ran along the dendrites, especially in the dendritic bundle. Occasionally a small bundle of unmyelinated fibers all contained the same kind of substance. Majority of the immunoreactive boutons formed axodendritic synapses. All the four kinds of neuroactive substancecontaining boutons or varicosities contained almost round clear vesicles or plus a few large granular vesicles. The SP and L-ENK varicosities included more large granular vesicles than the boutons did. Both symmetrical and asymmetical contacts were encountered in TH, 5-HT, SP and L-ENK boutons.