Evidence for dorsal root projection to somatostatin-immunoreactive structures in laminae I-II of the spinal dorsal horn.
In order to determine if somatostatin (SOM)-immunoreactive (I) cell bodies and processes in lamina (L) II of the rat spinal cord receive dorsal root input, the latter were anterogradely labeled by wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP). SOM-I structures were demonstrated by immunohistochemistry. Cell bodies labeled transscellularly or transsynaptically by WGA-HRP and immunohistochemically for SOM were present in L II. In addition, a L I cell was double labeled. These results suggest that some dorsal root axons innervate SOM-I neurons in L I-II of the spinal cord. In addition to confirming immunohistochemical observations in published reports, we have revealed SOM-I central terminals in the type II glomerulus. Further, a SOM-I CI-terminal, presumed to be of primary afferent origin, contacted a SOM-I dendrite in L II. Since SOM has been implicated in nociceptive function in the dorsal horn, it is possible that some of the SOM-I structures identified are involved in nociceptive processing.
Department of Anatomy, Tongji Medical University, Wuhan, China.
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D000818:Animals; D001560:Benzidines; D002863:Chromogenic Compounds; D005260:Female; D006651:Histocytochemistry; D007124:Immunoenzyme Techniques; D008854:Microscopy, Electron; D009434:Neural Pathways / Q000648:ultrastructure; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000032:analysis*; D013116:Spinal Cord / Q000648:ultrastructure*
D001560:Benzidines; D002863:Chromogenic Compounds; C021758:3,3',5,5'-tetramethylbenzidine; D013004:Somatostatin