ABSTRACT
This chapter examines briefly the evidence for direct autonomic innervation of lymphoid organs, particularly by the noradrenergic postganglionic sympathetic nerves. Evidence from several fields of investigation indicates a bidirectional link between the nervous system and the immune system. A search for the identification of specific circuitry involved in neural-immune interactions was undertaken with lesion studies in the central nervous system. Both the neuroendocrine and efferent autonomic systems produce biologically active molecules that can interact with cells of the immune system through cell surface or intracellular receptors. Both primary lymphoid organs and secondary lymphoid organs are innervated by noradrenergic nerves derived from ganglia of the sympathetic nervous system. Noradrenergic nerve fibers innervate the bone marrow and thymus. Noradrenergic fibers arising from mesenteric ganglia distribute to the gut and follow a specific pattern of innervation of Gut-Associated Lymphoid Tissue. Norepinephrine is present in nerves in specific compartments of both primary and secondary lymphoid organs.
