Distribution of locus coeruleus axons in the rat spinal cord: a combined anterograde transport and immunohistochemical study.

The distribution of locus coeruleus axons in the rat spinal cord was studied by anterograde transport of Phaseolus vulgaris leucoagglutinin in combination with dopamine-beta-hydroxylase immunohistochemistry. Locus coeruleus axons were observed primarily in the superficial laminae of the dorsal horn. Few locus coeruleus fibers were seen in the vicinity of motoneuron pools or in the intermediolateral cell column of the thoracic spinal cord. The results of this study suggest a selective action of the coeruleo-spinal projection upon sensory inputs to the spinal cord.