Distribution of preganglionic terminals in the cervical sympathetic ganglia detected by the expression of c-Fos like protein after electric stimulation of the ventral root.

To determine the segmental relationship between the upper thoracic spinal cord and cervical sympathetic ganglia, we observed the distribution pattern of postganglionic cells which expressed c-Fos like protein, one of the products of immediate early genes, after electrical stimulation of ventral roots at the T1-T3 spinal segments. We recognized a clear segmental arrangement of postganglionic cells in the stellate ganglion along its rostrocaudal direction corresponding to the segmental arrangement of preganglionic neurons in the spinal cord. That is, postganglionic neurons which expressed c-Fos like protein after stimulation of the T1 ventral root were distributed in the middle region of the stellate ganglion in the rostrocaudal direction. The c-Fos like protein-positive neurons after stimulation of the T2 ventral root were distributed in a more caudal region of the stellate ganglion than after T1 ventral root stimulation. C-Fos like protein-positive neurons after stimulation of the T3 ventral root were mainly situated in a more caudal region of the stellate ganglion than after T2 ventral root stimulation. There was, however, no segmental relationship between the upper thoracic levels of the spinal cord and superior cervical ganglion in the rostrocaudal direction. These results indicate that the segmental innervation of the upper thoracic spinal cord exists in the stellate ganglion, but not in the superior cervical ganglion.