Substance P-containing pathways to avian sympathetic preganglionic neurons: evidence for major spinal-spinal circuitry

摘要: The origin of substance P-like immunoreactivity (SPLI) in the neuropil sympathetic preganglionic neurons (SPNs) was investigated pigeon (Columba livia). Previous investigators had suggested that a major SPLI-containing projection to SPNs arose from caudal brainstem (Johansson, O., T. Hokfelt, B. Pernow, S. L. Jeffcoate, N. White, H. W. M. Steinbusch, A. J. Verhofstad, P. C. Emson, and E. Spindel (1981) Neuroscience 6: 1857-1881; Gilbert, R. F. T., P.C. Hunt, G. Bennett, Marsden, Sandberg, Verhofstad (1982) 7: 69-87; Helke, Neil, V. Massari, D. Loewy Brain Res. 243: 147-152) and, furthermore, bulbospinal fibers terminals SPN which contained SPLI also serotonin-like (5-HTLI) C.A. 69-87). In present study, various spinal lesions were made 5-HTLI content thoracic cord examined using immunohistochemistry. Interruption descending by cervical hemisection no demonstrable effect on neuropil, while almost totally depleted half gray (including cell column) ipsilateral hemisection. Following complete transection, only 2 3 mm rostral lesion, normal staining remainder cord. transection. Dorsal rhizotomy three six sequential segments significantly dorsal horn but region SPNs. Major depletion within column seen when portions isolated transections or unilateral hemisections. Finally, evidence found for intraspinal fiber systems. These results demonstrate majority is probably origin. data confirm axons arising bodies supraspinal