Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9886090 | Biochimica et Biophysica Acta (BBA) - General Subjects | 2005 | 9 Pages |
Abstract
Exposure of pheochromocytoma (PC 12) cells to a time-varying 1.51 T magnetic field inhibited an increase in the intracellular Ca2+ concentration ([Ca2+]i) induced by addition of caffeine to Ca2+-free medium. This inhibition occurred after a 15-min exposure and was maintained for at least 2 h. [Ca2+]i sharply increased in cells loaded with cyclic ADP-ribose, and 2-h exposure significantly suppressed the increase. Addition of ATP induced a transient increase in intracellular Ca2+ release mediated by IP3 receptor, and this increase was strongly inhibited by the exposure. Results indicated that the magnetic field exposure strongly inhibited Ca2+ release mediated by both IP3 and ryanodine receptors in PC 12 cells. However, thapsigargin-induced Ca2+ influx (capacitative Ca2+ entry) across the cell membrane was unaffected. The ATP content was maintained at the normal level during the 2-h exposure, suggesting that ATP hydrolysis was unchanged. Therefore, Mg2+ which is known to be released by ATP hydrolysis and inhibit intracellular Ca2+ release may not relate the exposure-caused inhibition. Eddy currents induced in culture medium appear to change cell membrane properties and indirectly inhibit Ca2+ release from endoplasmic reticulum and other Ca2+ stores in PC 12 cells.
Related Topics
Life Sciences
Biochemistry, Genetics and Molecular Biology
Biochemistry
Authors
Toshitaka Ikehara, Hisao Yamaguchi, Keiko Hosokawa, Hitoshi Houchi, Ki Ho Park, Kazuo Minakuchi, Hideki Kashimoto, Mitsuo Kitamura, Yohsuke Kinouchi, Kazuo Yoshizaki, Hiroshi Miyamoto,