Preganglionic neurons projecting to the first thoracic sympathetic ganglion in the terrapin (Trionyx sinensis).
After injection of HRP into the first right thoracic sympathetic ganglion of the terrapin, labeled cells are found in the central autonomic area, intercalated area, intermediolateral cell column, dorsal horn, ventrolateral edge of the dorsal column, dorsolateral edge of the ventral white column, and the ventral and ventromedial border of the ventral horn. They form one discontinuous column in the portion of the spinal cord marking the attachments of the tenth or eleventh to the fourteenth spinal nerves. The preganglionic neurons consist of small (8-9 micron), medium-sized (10-16 micron) and large (18-20 micron) cells. The number of labeled neurons in individual animals varies between 154 and 541. They are found ipsilateral to the injected ganglia in all animals. In a few cases 1-2 labeled neurons are contralateral. The results are compared with previous work in birds and mammals.
D000818:Animals; D001339:Autonomic Fibers, Preganglionic; D005728:Ganglia, Sympathetic / Q000033:anatomy & histology*; D013116:Spinal Cord / Q000033:anatomy & histology*; D014426:Turtles / Q000033:anatomy & histology*