Regulation of adrenomedullin and its receptor complexes due to pneumonia and mechanical ventilation. Pneumococcal pneumonia (S.p.) was induced 24 hours before mechanical ventilation (MV) was performed for 6 hours. Nonventilated (NV) mice were sacrificed 30 hours after infection. Regulation of (A) adrenomedullin (AM) and (C) its receptor components calcitonin receptor-like receptor (CRLR) and receptor activating modifying protein (RAMP)- 1, 2 and 3 were quantified by quantitative real-time polymerase chain reaction in lung homogenate (*P < 0.05; **P < 0.01, n = 5). Note that the receptor expression data for the NV and MV groups without infection have been published previously . (B) Immunofluorescence analysis of lung tissue. AM-immunolabeling was enhanced in MV mice compared with NV mice. In pneumonic infiltrates, leukocytes showed intense AM-immunolabeling. Representative images from five animals per group are shown.