ISSN:
0263-6484
Keywords:
Hyperthermia
;
intracellular calcium
;
fura-2
;
ATP
;
D-myo-inositol 1,4,5-triphosphate
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
Effects of hyperthermia on the intracellular calcium concentration (Cai) of an established mouse breast cancer cell line, MMT060562, were studied using fura-2 fluorescence microscopy and the whole-cell clamp technique. A sudden change of temperature from 37 to 45°C induced a transient increase in the fluorescence ratio permeability of the cell membrane and inward current. Deletion of extracellular calcium abolished the fluorescence ratio response to the rise in temperture. Cai of some cells increased after hyperthermia treatment at 44-48°C for 20 min, but the average increase of Cai was negligible. After hyperthermia treatment, spontaneous oscillation of Cai, chemical responses to ATP and bradykinin and the mechanically-induced spreading reponse diminished. However, the mechanically induced increase of Cai within the stimulated cell remained even after hyperthermia treatment. Suppression of the ATP-induced Cai response recovered to about half the original level within 12 h. Blockage of protein synthesis with cycloheximide (100 μM) had no effect on the recovery. The D-myo-inositol 1,4,5-triphosphate (IP3)-dependent increase of Cai remained intact even after hyperthermia treatment. It is concluded that hyperthermia treatment increases both the permeability of the cell membrane and Cai, but decreases the sensitivity of cells to ATP and bradykinin, presumably due to modification of the signal transduction mechanism.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cbf.290100403
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