Answers are grounded in this paper and cite their sources.
Enkephalin distribution was examined in autonomic areas of the rat thoracic spinal cord. The localization of enkephalin fibers coincided with nuclear regions containing sympathetic preganglionic neurons. Horizontal sections revealed a pattern for enkephalin fibers resembling Laruelle's description of the localization of sympathetic preganglionic neurons as rungs of a ladder.
No takes yet. Share an insight, caveat, or question.
Romagnano et al. (1984) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: