Enhanced secretion of substance P by cytokine-stimulated rat brain endothelium cultures

Substance P (SP) was analyzed in rat brain endothelium cultures after cytokine stimulation. SP secretion was found after stimulation with high doses of interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha). High doses of interferon-gamma (INF-gamma) had no effect on this secretion. Elevated SP release was found to be associated with mRNA expression of beta-preprotachykinin (beta-PPT), precursor of SP, in the cells. Under cytokine stimulation, part of SP was bound to brain endothelial cell surface, suggesting the existence of an autocrine network for this neuropeptide. These findings suggest that SP may have an immunomodulatory action at the blood-brain barrier during inflammatory and autoimmune processes in the central nervous system.