ABSTRACT
The distribution of somatostatin (SRIF) in substantia gelatinosa of the rat spinal cord was studied by means of immuno-electron microscopy. The ultrastructural features showed that nerve terminals containing SRIF take part in forming presynap- tie elements of axe-somatic, axe-dendritic and axo-axonic synapses. The immune- reactive products locatl at the external membrane of mitochondria, around the small clear synaptie vesicles and in the large granular vesicles. Most of synaptic vesicles are round or ovoid in shape. Only a few of them are flattened. Based on the ultrastructural characteristics mentioned above and related experimental results the authors believe that SRIF in substantia gelatinosa of the rat spinal cord is probably involved as a neurotransmitter instead of neuromodulator.
ABSTRACT
The orientational projections of sensory fibres of radial nerve and ulnar nerve to the substantia gelatinosa(SG) of the spinal cord in rats were studied in accordance with the principle of transganglion degeneration by using the acid phosphatase technique.It was found that the affeernt fibers of the radial nerve projected chiefly to SG, from the upper part of C_6 to the middle part of T_1 longitudinally; the ulnar nerves projected chiefly to SG from the middle part of C_6 to the middle part of T_1.In their transverse projections,the afferent fibres of the radial nerve were mainly found in the region of the whole area of the middle 1/3 of SG; and the afferent fibres of ulnar nerve were found within the centre line of SG, and mainly in the region of the lateral 1/2～3/4 at medial half. In summary, radial nerve projected to the lateral region and ulnar nerve to the medial region of SG.