THE LOCATION AND CHARACTERISTICS OF SYMPATHETIC PREGANGLIONIC NEURONES IN THE LOWER THORACIC SPINAL CORD OF DOG AND CAT

¹ Departments of Cardiovascular Studies and Physiology, Worsley Medical and Dental Building, The University, Leeds LS2 9JT
² Department of Anaesthesia, The University of Leeds, Leeds, LS2 9JT
³ Department of Physiology, Marischal College, University of Aberdeen, Aberdeen

The retrograde transport of horseradish peroxidase from a white ramus communicans has been used to define the precise segmental location of sympathetic preganglionic cell bodies in the spinal cord of the cat and dog. All labelled cells were found ipsilaterally and were confined to the spinal cord segment from which the ramus originated. Most lay in the intermediolateral cell column and the immediately adjacent white matter, though others were scattered in more medial areas of the grey matter. We suggest that the observed distribution of sympathetic preganglionic neurones, the orientation of their processes and the paths taken by their axons are a direct result of cell migration during the embryological development of the spinal cord.