[Distribution of preganglionic cells of superior cervical ganglion in the spinal cord in the cat].

It is generally accepted that preganglionic neurons of the cervical sympathetic nerve arise from the ciliospinal center, which exists in the spinal cord over C8-T3. However, its distribution within the spinal cord has not been exactly demonstrated. Therefore, horseradish peroxidase (HRP) was injected into the cervical sympathetic trunk in order to demonstrate the distribution of preganglionic neurons in the spinal cord in the cat. Four adult cats were used. HRP was injected into the superior cervical sympathetic trunk. Two or three days after the injection cats were sacrificed and prepared for histochemical demonstration of HRP. The superior cervical ganglion, sympathetic trunk and spinal cord were examined. Labelled cells with HRP were found in the intermediolateral nucleus over C8-T6 on the ipsilateral side of the injection. These neurons were identified as preganglionic neurons of the cervical sympathetic nerve. In addition, a large number of labelled cells were seen at the T2 and T3 levels, but a few labelled cells were observed at C8, T5 and T6. T1 and T4 showed the moderate distribution. Preganglionic neurons in the ciliospinal center were located at the level from C8 to T6 of the spinal cord.