Ca2+ oscillation and c-fos gene expression induced via muscarinic acetylcholine receptor in human T- and B-cell lines.
We previously reported that blood acetylcholine (ACh) mainly originates from T-lymphocytes and that muscarinic (Ms) ACh receptor mRNA is expressed in both T- and B-lymphocytes. In the present study, we used confocal laser scanning microscopy and fluo-3, a calcium-sensitive indicator, to investigate the effects of Ms-ACh receptor agonists on the intracellular free Ca2+ concentration ([Ca2+]i) in single cells from human T-cell (CEM) and B-cell (Daudi) lines, which we used as models of lymphocytes. In both cell lines, stimulation of Ms-ACh receptors with ACh (0.1-100 microM), bethanechol (100 microM), car-bachol (100 microM) or oxotremorine-M (Oxo-M; 0.1-100 microM) induced [Ca2+]i-dependent increases in fluo-3 fluorescence, which in the presence of extracellular Ca2+ were followed by oscillations in [Ca2+]i that persisted for at least 10 min. All effects were completely blocked by atropine (1 microM), an Ms-ACh receptor antagonist. In both cell lines Oxo-M (100 microM) up-regulated expression of c-fos mRNA in an extracellular Ca2+-dependent manner. Again, the effect was blocked by 1 microM atropine. These results provide the first evidence that stimulation of Ms-ACh receptors induces Ca2+ oscillations and up-regulates c-fos gene expression in T- and B-lymphocytes, which is consistent with the notion that ACh released from T-lymphocytes triggers nuclear signaling via Ms-ACh receptors.
Department of Pharmacology, Kyoritsu College of Pharmacy, Tokyo, Japan.
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D000109:Acetylcholine / Q000494:pharmacology; D001285:Atropine / Q000494:pharmacology; D001402:B-Lymphocytes / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects*; D016762:Genes, fos / Q000187:drug effects*; D006801:Humans; D007938:Leukemia / Q000473:pathology; D018613:Microscopy, Confocal; D018721:Muscarinic Agonists / Q000494:pharmacology; D018727:Muscarinic Antagonists / Q000494:pharmacology; D010095:Oxotremorine / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011976:Receptors, Muscarinic / Q000187:drug effects*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000187:drug effects*
D018076:DNA, Complementary; D018721:Muscarinic Agonists; D018727:Muscarinic Antagonists; D012333:RNA, Messenger; D011976:Receptors, Muscarinic; D010095:Oxotremorine; D001285:Atropine; D000109:Acetylcholine; D002118:Calcium