These studies identify a further abnormality in cystic fibrosis (CF). The increase in intracellular free calcium contration ([Ca2+]i,) after exposure to histamine and PGE1, is demonstrated to be abnormally low in nasal cells, studied in short-term culture, from patients with CF compared with control subjects. [Ca2+]i, is measured by using the Ca2+sensitive fluorescent dye fura-2 and a fluorescence microscope imaging system. The percentage of CF cells that increase [Ca2+]i in response to histamine is decreased compared with controls, and, even in those CF cells that increase [Ca2+]i, the magnitude of the increase in [Ca2+]i in response to histamine is smaller than in controls. When exposed to PGEi, a similar number of control and CF cells responded with an increase in [Ca2+]i, but again the magnitude of the response was smaller in the CF ceHs. The mechanism of the PGE,-induced increase in [Ca2+]i is not mediated by cAMP, since 8-bromo-cAMP failed to increase [Ca2+]i in these cells. This abnormality in [Ca2+]i) response did not apply to all secretagogues, with the response to carbachol being similar in CF and normal cells. How the abnormal CF gene product accounts for the abnor-mality hi intracellular Ca2+ response to some but not all secretagogues is unknown.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - 1992|
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