Identification and localization of sympathetic preganglionic neurons by horseradish peroxidase

Using the technique of retrograde degeneration many investigators have shown that sympathetic preganglionic neurons are located in the intermediolateral cell column of the thoraco lumbar spinal cord. The present study used the horseradish peroxidase technique to verify the location, distribution and size of the preganglionic sympathetic cell bodies. In recent years horseradish peroxidase has been used as a neuroanatomical tracing material because it is taken up from the axon terminals and transported to the cell bodies. Horseradish peroxidase was injected into the stellate ganglion or superior cervical ganglion of adult cats anesthetized with sodium pentobarbital (35mg/kg). After survival time of 1 to 3 days the cats were sacrificed and spinal cord sections were prepared and examined following incubation in a buffer solution containing hydrogen peroxide and 3,3- diaminobenzedine tetrahydrochloride. Most of the labeled neurons were located in the intermediolateral cell column, especially at the junction of the gray and white matter. Some cells were located in the white matter and intermediomedial cell column. The cell body diameter ranged from 15 to 30 microns. No cells were found contralateral to the site of injection.