Distribution of Tyrosine Hydroxylse Immunoreactive Structure in the Spinal Cord and Dorsal Root Ganglion of the Rat

Kim, Yong Joo; Kim, Ji Yoon; Kim, Dong Sun; Jo, Hee Joong; Bae, Yong Chul; Park, Mae Ja

Abstract

With the aim of gaining more insight into the catecholaminergic system in the nervous system of the rat, we have studied the precise distribution pattern of the tyrosine hydroxylase immunoreactive[TH-IR] fibers and soma in the spinal cord and dorsal root ganglion. In the dorsal root ganglion[DRG], TH-IR fibers were observed to run along the vessel wall, spirally and not found in the neural tissue itself. A few TH-IR fibers were found in the spinal nerve, not in the ventral root. Many TH-IR neurons were distributed in the L3, 4, 5, and 6 DRG but none of them were found in the other DRG segments. In the spinal cord, TH-IR fibers have shown sparse distribution all over spinal cord but relatively dense distribution in the ventral horn, intermediolateral column, lamina I of the dorsal horn of the cervical, lumbar, sacral, and coccygeal segment. TH-IR neurons were found in the intermediolateral column, dorsal gray commissure, dorsal horn of the C1 and C2 segments and S1-4 segments. TH-IR neurons in the cervical segments were polygonal and spindle shaped with well developed processes. In contrast to this, TH-IR neurons in the sacral segments were oval or spindle shaped with no processes. In conclusion, neurons in the DRG were not influenced by catecholaminergic nervous input. Intrinsic catecholaminergic nervous systems were found in both of spinal cord and DRG.