Jk. Elmquist et Cb. Saper, ACTIVATION OF NEURONS PROJECTING TO THE PARAVENTRICULAR HYPOTHALAMIC NUCLEUS BY INTRAVENOUS LIPOPOLYSACCHARIDE, Journal of comparative neurology, 374(3), 1996, pp. 315-331
The central nervous system interacts with the immune system to coordin
ate several components of the acute phase response, although the speci
fic neuroanatomical pathways that mediate these responses are still un
characterized. However, neurons in both the autonomic and endocrine co
mponents of the paraventricular hypothalamic nucleus (PVH) are charact
eristically activated in different models of immune stimulation. In th
e current study, we have used intravenous administration of lipopolysa
ccharide (LPS; 5 or 125 mu g/kg) to induce the acute phase response. W
e subsequently coupled immunohistochemistry for Fos (as a marker of ne
uronal activation) with retrograde transport of the neuroanatomical tr
acer cholera toxin-b from the PVH. Several of the activated cell group
s directly projected to the paraventricular nucleus, including the vis
ceromotor (infralimbic) cortex, median preoptic nucleus, ventromedial
preoptic area, bed nucleus of the stria terminalis, parabrachial nucle
us, ventrolateral medulla, and nucleus of the solitary tract. These fi
ndings indicate that immune system stimulation activates cell groups f
rom multiple nervous system levels that project to the paraventricular
nucleus. We hypothesize that the activation of specific autonomic and
endocrine elements of the PVH may be due to the activity of distinct
afferents that converge on the PVH from multiple components of the cen
tral autonomic control system. Our results are consistent with the hyp
othesis that the PVH plays a key role in integrating diverse physiolog
ical cues into the varied manifestations that constitute the cerebral
component of the acute phase response. (C) 199s Wiley-Liss, Inc.