Brain research. Molecular brain research
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Brain Res. Mol. Brain Res. · Apr 2001
Cardiovascular responses to subseptic doses of endotoxin contribute to differential neuronal activation in rat brain.
The contribution of cardiovascular activity in the early central responses to systemic inflammation was assessed in rats following intravenous administration of subseptic doses of lipopolysaccharide (LPS). LPS at 12.5 microg/kg increased heart rate (HR) but did not alter mean arterial pressure (MAP), and induced interleukin-1 beta (IL-1 beta) gene expression at 1 h in circumventricular organs (CVOs), choroid plexus, meninges, blood vessels, and pituitary gland. IL-1 beta mRNA levels were attenuated at 2 h in most regions studied. ⋯ After 2 h, FLI was widespread throughout the brain. Plasma ACTH levels were elevated at 1 and 2 h in response to both doses of LPS, and levels of CRF mRNA were increased after 2 h in the parvocellular PVN. Our results reveal that central responses to increasing doses of LPS show different patterns which are related to activation of distinct immune and viscerosensory pathways, and that cardiovascular responses contribute to early neuronal activation as LPS concentrations are increased.