THORACOLUMBAR SYMPATHETIC PREGANGLIONIC NEURONS IN THE DORSAL COMMISSURAL NUCLEUS OF THE MALE-RAT - AN IMMUNOHISTOCHEMICAL STUDY USING RETROGRADE LABELING OF CHOLERA-TOXIN SUBUNIT-B
Y. Hosoya et al., THORACOLUMBAR SYMPATHETIC PREGANGLIONIC NEURONS IN THE DORSAL COMMISSURAL NUCLEUS OF THE MALE-RAT - AN IMMUNOHISTOCHEMICAL STUDY USING RETROGRADE LABELING OF CHOLERA-TOXIN SUBUNIT-B, Experimental Brain Research, 98(1), 1994, pp. 21-30
The cell morphology of sympathetic preganglionic neurons (SPNs) in the
dorsal commissural nucleus was studied by the retrograde labeling tec
hnique using cholera toxin subunit B (CTb) as a tracer. A small amount
of an aqueous solution of CTb was injected unilaterally into the majo
r pelvic ganglion of the male rat. Labeled SPNs were detected immunohi
stochemically using anti-CTb antiserum. Most of the labeled SPNs were
observed in L1 to L3, and a very small number in T13. They were observ
ed bilaterally in the sympathetic nuclei, such as the intermediolatera
l cell column, intercalated nucleus and the dorsal commissural nucleus
. A loose network of longitudinally or transversely oriented SPN dendr
ites was located within the dorsal commissural nucleus itself. The lat
eral margin of the dorsal commissural nucleus was roughly demarcated b
y longitudinally oriented dendrites. Together with the dendrites of th
e SPNs of the intercalated and intermediolateral cell column, laterall
y oriented dendrites of the dorsal commissural nucleus converged and f
ormed the transverse dendritic bundles in the intermediate zone that c
onnect the dorsal commissural nucleus and the intermediolateral cell c
olumn. The transverse dendritic bundles were arranged periodically. Th
e axons of the SPNs in the dorsal commissural nucleus traveled lateral
ly into the transverse dendritic bundles, then turned ventrally near t
he intermediolateral cell column, and finally entered the ventral funi
culus. After rhizotomy of the ventral roots of the upper lumbar cord,
labeled SPNs were found only on the side contralateral to the rhizotom
y. The dorsal commissural nucleus appears as a compact single cell col
umn, but our results clearly show that this nucleus actually consists
of two adjacent parallel columns of cells.