title: Influence of protein kinase C, cAMP and phosphatase activity on histamine release produced by compound 48/80 and sodium fluoride on rat mast cells.
abstract: We have studied the effect of protein kinase C and protein kinase A activation, and phosphatase inhibition on two different stimuli with distinct mechanisms of action. The first stimulus is compound 48/80, and its action is mediated probably by a Gi-protein, while the other is sodium fluoride, which unspecifically activates G-proteins. We established a comparative study because the action of compound 48/80 is calcium-independent, while fluoride is strictly calcium-dependent. The activation of protein kinase C was attained with the phorbol esther 12-O-tetradecanoylphorbol-13-acetate, protein kinase A was activated by increasing cAMP levels with forskolin or rolipram, and the phosphatase activity was inhibited with okadaic acid (OA), which inhibits phosphatases type 1 and 2A. Our results show that OA enhances the response to fluoride and compound 48/80 in the absence of calcium, and we conclude that calcium has a negative feedback role on the cell response. Protein kinase A activation strongly inhibits the response to fluoride, and the results show a positive regulation of protein kinase C and a negative regulation of protein kinase A over fluoride response. As previously reported by other authors for the ionophore A23187, TPA notably potentiates the response to fluoride, which supports its possible modulatory role on extracellular calcium-dependent stimuli.
mesh_terms: D000818:Animals; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D004789:Enzyme Activation / Q000502:physiology; D004988:Ethers, Cyclic / Q000494:pharmacology; D006636:Histamine Release / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D008407:Mast Cells / Q000187:drug effects / Q000502:physiology*; D019319:Okadaic Acid; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism; D011760:Pyrrolidinones / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020889:Rolipram; D012969:Sodium Fluoride / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
chemical_list: D004988:Ethers, Cyclic; D010726:Phosphodiesterase Inhibitors; D011760:Pyrrolidinones; D005576:Colforsin; D019319:Okadaic Acid; D003189:p-Methoxy-N-methylphenethylamine; D012969:Sodium Fluoride; D000242:Cyclic AMP; D011494:Protein Kinases; D011493:Protein Kinase C; D010749:Phosphoprotein Phosphatases; D020889:Rolipram; D013755:Tetradecanoylphorbol Acetate