There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
By the use of light microscopic (LM) immunohistochemistry, the presence of peptides
and of dopamine beta-hydroxylase (DBH) in nerves supplying mammalian (guinea pig,
rat, cat, pig, mouse, human) lymph nodes were examined. In all species, lymph nodes
of various somatic and visceral regions were found to contain nerve fibers which stained
for neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), peptide histidine
isoleucine (PHI), substance P (SP), calcitonin gene-related peptide (CGRP) or DBH.
SP- and CGRP-immunoreactive (ir) fibers completely overlapped and exhibited the widest
distribution. They were present in perivascular, paravascular and many non-vascular
fibers travelling in close contact with lymphoid cells. In contrast, NPY-ir fibers
coincided with those staining for DBH, prevailed in perivascular plexus and only rarely
branched off into lymphoid parenchyma. Alternate staining of adjacent sections revealed
that SP/CGRP-ir fibers were different from NPY/DBH-ir fibers. The distribution of
VIP-ir fibers was identical to that of PHI-ir fibers and partially overlapped with
that of ir-NPY/DBH or ir-SP/CGRP fibers. We conclude that the NPY innervation of lymph
nodes is sympathetic noradrenergic while nerves coding for co-existing SP and CGRP
are most likely of sensory origin. The nerves containing co-existing VIP and PHI may
be of heterogenous origin (sensory, cholinergic sympathetic, and/or parasympathetic).
We suggest that these distinct sensory and autonomic peptidergic pathways linking
the nervous system with the lymph nodes may play a differential role in bidirectional
neuroimmunomodulation.