Cyclic AMP is not a direct regulator of calcium flux and hydrolysis of phosphoinositides in human lymphocytes.
The regulatory effects of adenosine 3',5'-cyclic monophosphate (cAMP) on Ca2+ flux and phosphatidylinositol (PI) turnover in human lymphocytes were studied. cAMP did not affect the intracellular accumulation of Ca2+ induced by phytohemagglutinin (PHA) and histamine-trifluoromethyl toluidide derivative (HTMT) in peripheral blood lymphocytes (PBL). In addition, cAMP also did not alter Ca2+ flux induced by PHA, anti-CD3, or PAF in T cells, or by anti-IgM and HTMT in non-rosetted cells. Similarly, cAMP did not inhibit IP accumulation induced by HTMT in PBL, anti-CD3 in T cells, and by anti-IgM or HTMT in non-rosetted cells. The only exception was the synthesis of IP induced by PHA in T cells that was inhibited by cAMP. Furthermore, prolonged treatment of T cells with cholera toxin inhibited Ca2+ accumulation in response to CD3. The degree of inhibition of Ca2+ and IP responses was not proportional to the levels of intracellular cAMP generated.
Department of Medicine Division of Clinical Pharmacology, Stanford University School of Medicine, CA.
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D000888:Antibodies, Anti-Idiotypic; D001402:B-Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D017252:CD3 Complex / Q000276:immunology; D002118:Calcium / Q000097:blood*; D002772:Cholera Toxin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism* / Q000494:pharmacology; D015232:Dinoprostone / Q000494:pharmacology; D006632:Histamine / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D006868:Hydrolysis; D007075:Immunoglobulin M / Q000276:immunology; D007295:Inositol Phosphates / Q000097:blood*; D010835:Phytohemagglutinins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D014052:Toluidines / Q000494:pharmacology
D000888:Antibodies, Anti-Idiotypic; D017252:CD3 Complex; D007075:Immunoglobulin M; D007295:Inositol Phosphates; D010835:Phytohemagglutinins; D014052:Toluidines; C081972:6-((2-(4-imidazolyl)ethyl)amino)heptanoic acid 4-toluidide; D006632:Histamine; D002772:Cholera Toxin; D000242:Cyclic AMP; D015232:Dinoprostone; D002118:Calcium