@article{oai:nagoya.repo.nii.ac.jp:00009907,
 author = {SATO, Koichi and TORIHASHI, Shigeko and HORI, Masatoshi and NASU, Tetsuyuki and OZAKI, Hiroshi},
 issue = {10},
 journal = {The journal of veterinary medical science},
 month = {Oct},
 note = {Intestinal muscularis resident macrophages distributed in myenteric region may play an important role in the immunological host defense against infection. In this study, we investigated the phagocytic stimulation of resident macrophages on cyclooxygenase-2 (COX-2) expression and smooth muscle contraction in the small intestine of rat. After the injection of FITC-dextran to rat, phagocytosed macrophages could be detected in the myenteric plexus. FITC-positive macrophages were also immunostained with COX-2 antibody. The number of COX-2 immunopositive cells increased in a time-dependent manner reaching its maximum at 4hr after the injection, which then decreased gradually but considerable number of cells were still remained on 7 days. The injection of FITC-dextran, however, did not change the population of ED2-positive resident macrophages even on 7 days. Production of PGE_2 was significantly higher in the dextran treated tissue as compared to control tissue. In the smooth muscle tissue phagocytosed dextran,  carbachol-induced contraction was significantly decreased. The suppression of the carbachol-induced contraction was completely restored by COX inhibitor, indomethacin. Finally we demonstrated that, in freshly isolated macrophage cells, addition of dextran induced a slow and sustained increase in intracellular Ca^<2+> concentration. These results indicate that phagocytotic activation of muscularis resident macrophages induces COX-2 gene expression and then results in production of PGE_2 to suppress the smooth muscle contractile activity., (Pharmacology)},
 pages = {1053--1060},
 title = {Phagocytotic Activation of Muscularis Resident Macrophages Inhibits Smooth Muscle Contraction in Rat Ileum},
 volume = {69},
 year = {2007}
}