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MEMBRANE TRANSPORTERS, ION CHANNELS, AND PUMPS
Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
Submitted 7 October 2002 ; accepted in final form 27 April 2003
We have previously demonstrated that dietary histamine is accumulated in
the spleens of L-histidine decarboxylase (HDC)-deficient mice,
which lack endogenous histamine synthesis. To characterize the clearance
system for dietary histamine in mice, we investigated the cell type and
mechanism responsible for histamine uptake in the spleens of HDC-deficient
mice. Immunohistochemical analyses using an antihistamine antibody indicated
that a portion of the CD14+ cells in the spleen is involved in
histamine storage. Peritoneal macrophages obtained from Balb/c mice and a
mouse macrophage cell line, RAW264.7, had potential for histamine uptake,
which was characterized by a low affinity and high capacity for histamine. The
histamine uptake by RAW264.7 cells was observed at physiological temperature
and was potently inhibited by pyrilamine, chlorpromazine, quinidine, and
chloroquine, moderately inhibited by
N
-methylhistamine, dopamine, and serotonin, and not
affected by tetraethylammonium and 1-methyl-4-phenylpyridinium. Intracellular
histamine was not metabolized in RAW264.7 cells and was released at
physiological temperature in the absence of extracellular histamine. These
results suggest that histamine uptake by macrophages may be involved in the
clearance of histamine in the local histamine-enriched environment.
cation transporter; chlorpromazine; pyrilamine; quinidine
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