ACUTE STRESS AFFECTS CYTOKINES AND NITRIC-OXIDE PRODUCTION BY ALVEOLAR MACROPHAGES DIFFERENTLY

The production of cytokines by alveolar macrophages was studied after exposure of rats to an acute stress paradigm (mild inescapable footsho cks). When alveolar macrophages from nonstressed animals were isolated and cultured, they readily produced interleukin-1 beta (IL-1 beta), I L-6, and tumor necrosis factor-alpha (TNF-alpha) after stimulation wit h lipopolysaccharides (LPS). For these cytokines the dose response rel ationship for LPS was clearly biphasic. Nitric oxide (NO) production c ould only be detected upon LPS stimulation and seemed to be monophasic . However, when the animals were exposed to the acute stress paradigm, isolated alveolar macrophages (AM) showed a marked increase of IL-1 b eta and TNF-alpha secretion upon LPS stimulation in vitro, but no chan ges in the production of IL-6 were detected. In contrast, exposure to the stress paradigm resulted in a strong decrease in NO production. Th e results indicate that emotional stress can rapidly induce altered be havior of AM, which is discussed in view of the important role these c ells play in the regulation of the local immune responses in the lungs and the possible contribution to asthma.